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2-Ethylhexanoic Acid — label CAS 149-57-5

2-Ethylhexanoic Acid

CAS 149-57-5 C8H16O2 Other SDS published CLP Warning
MolGod_SDSCARD_1
REACH 2020/878
v3 · 21.09.2026

Specification

MFC8H16O2
Molecular weight144.21

Values are typical for the standard grade. Tighter specifications are available — state the target in your inquiry and we confirm against the production batch.

Hazard classification

GHS pictogram GHS08 — Health hazard

Warning

Classification source — PubChem C&L (consensus filter, not harmonised)

No harmonised entry exists for this substance; the classification shown is the supplier consensus reported to ECHA and should be confirmed for your intended use.

  • H361 Suspected of damaging fertility or the unborn child
Precautionary statements (24)
  • P203 Obtain, read and follow all safety instructions before use
  • P280 Wear protective gloves/protective clothing/eye protection/face protection
  • P318
  • P405 Store locked up
  • P501 Dispose of contents/container to an approved waste collection point
  • P260 Do not breathe dust/fume/gas/mist/vapours/spray
  • P264 Wash thoroughly after handling
  • P264+P265
  • P270 Do not eat, drink or smoke when using this product
  • P301+P330+P331
  • P302+P352
  • P302+P361+P354
  • P304+P340
  • P305+P351+P338
  • P305+P354+P338
  • P308+P316
  • P316
  • P317
  • P321 Specific treatment
  • P337+P317
  • P362+P364
  • P363 Wash contaminated clothing before reuse
  • P301+P317
  • P332+P317
Full safety data sheet CLP label (EN)

Substance identity verified against the registry entry on 2026-09-02.

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3D model 2-Ethylhexanoic Acid, CAS 149-57-5, molecular formula C8H16O2, molar mass 144.21 g/mol

Data transcribed from regulatory registers and technical literature, with the source and edition stated. It does not replace the supplier's safety data sheet. Fields without a recorded source are marked as such.

📊 Physicochemical data — CAS 149-57-5MolGod_PROPHUB_MAIN
📊 Physicochemical properties

Quick Reference

Formula: C8H16O2
MW: 144.21 g/mol
CAS: 149-57-5
🔬 Advanced Properties

Chemical Identifiers

SMILES: CCCCC(CC)C(=O)O

Last updated: unconfirmed

Chemical Overview: 2-Ethylhexanoic AcidMolGod_OVERVIEW_1
Molecular formulaC8H16O2[1]
Molecular weight144.21 g/mol[1]
Boiling point227.78 °C[1][2]
Density0.9 g/cm³[1]
LogP (lipophilicity)2.6[1]
IUPAC name2-ethylhexanoic acid[1]
SMILESCCCCC(CC)C(=O)O[1]
InChIKeyOBETXYAYXDNJHR-UHFFFAOYSA-N[1]

Synonyms: 2-ETHYLHEXANOIC ACID · 149-57-5 · 2-Ethylcaproic acid · Hexanoic acid, 2-ethyl- · Ethylhexanoic acid

Data sources: PubChem (NLM/NIH)
Last updated: 2026-09-21

📚 Scientific references (Chicago Author-Date) (2 sources)
  1. PubChem. National Center for Biotechnology Information (NIH/NLM), chemical compound database. ↗ dotyczy: Molecular formula · Molecular weight · Boiling point · Density · LogP (lipophilicity) · IUPAC name · SMILES · InChIKey
  2. NIST. Chemistry WebBook, SRD 69. National Institute of Standards and Technology. ↗ dotyczy: Boiling point

SCIENTIFIC RESEARCH

[1]PubMed2023
Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and…
Obringer C, Lester C, Karb M et al.. (2023). "Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situati
Go to full study ↗
[2]PubMed2001
Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.
French KJ, Strickler MD, Rock DA et al.. (2001). "Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.". Biochemistry. https://doi.org/
Go to full study ↗
[3]PubMed1998
2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.
Juberg DR, David RM, Katz GV et al.. (1998). "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.". Food and chemical toxicology : an international journal published for the B
Go to full study ↗
[4]PubMed1998
Altered zinc metabolism contributes to the developmental toxicity of 2-ethylhexanoic acid, 2-ethylhexanol and valproic acid.
Bui LM, Taubeneck MW, Commisso JF et al.. (1998). "Altered zinc metabolism contributes to the developmental toxicity of 2-ethylhexanoic acid, 2-ethylhexanol and valproic acid.". Toxicology. https://do
Go to full study ↗
[5]PubMed1993
Exposure of newborn infants to di-(2-ethylhexyl)-phthalate and 2-ethylhexanoic acid following exchange transfusion with polyvinylchloride catheters.
Plonait SL, Nau H, Maier RF et al.. (1993). "Exposure of newborn infants to di-(2-ethylhexyl)-phthalate and 2-ethylhexanoic acid following exchange transfusion with polyvinylchloride catheters.". Tran
Go to full study ↗
[6]PubMed1991
Distribution of 2-ethylhexanoic acid in mice and rats after an intraperitoneal injection.
Pennanen S, Manninen A. (1991). "Distribution of 2-ethylhexanoic acid in mice and rats after an intraperitoneal injection.". Pharmacology & toxicology. https://doi.org/10.1111/j.1600-0773.1991.tb01208
Go to full study ↗
[7]PubMed1987
Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.
Ritter EJ, Scott WJ Jr, Randall JL et al.. (1987). "Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.". Teratology. h
Go to full study ↗
📚 Scientific references (Chicago Author-Date) 7 refs · 1 baz

MOLECULE Per-CAS bibliography (live from 13+ databases)

Sources: db:pubmed (7)

  1. db:pubmed Obringer C, Lester C, Karb M et al.. (2023). "Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situation.". Regulatory toxicology and pharmacology : RTP. https://doi.org/10.1016/j.yrtph.2022.105315 →
  2. db:pubmed French KJ, Strickler MD, Rock DA et al.. (2001). "Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.". Biochemistry. https://doi.org/10.1021/bi010063+ →
  3. db:pubmed Juberg DR, David RM, Katz GV et al.. (1998). "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.". Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. https://doi.org/10.1016/s0278-6915(97)00168-3 →
  4. db:pubmed Bui LM, Taubeneck MW, Commisso JF et al.. (1998). "Altered zinc metabolism contributes to the developmental toxicity of 2-ethylhexanoic acid, 2-ethylhexanol and valproic acid.". Toxicology. https://doi.org/10.1016/s0300-483x(97)00171-6 →
  5. db:pubmed Plonait SL, Nau H, Maier RF et al.. (1993). "Exposure of newborn infants to di-(2-ethylhexyl)-phthalate and 2-ethylhexanoic acid following exchange transfusion with polyvinylchloride catheters.". Transfusion. https://doi.org/10.1046/j.1537-2995.1993.33793325058.x →
  6. db:pubmed Pennanen S, Manninen A. (1991). "Distribution of 2-ethylhexanoic acid in mice and rats after an intraperitoneal injection.". Pharmacology & toxicology. https://doi.org/10.1111/j.1600-0773.1991.tb01208.x →
  7. db:pubmed Ritter EJ, Scott WJ Jr, Randall JL et al.. (1987). "Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.". Teratology. https://doi.org/10.1002/tera.1420350107 →
Regulatory status of the substance
This substance is subject to regulatory requirements: hazardous waste management (BDO register). Details in the \"Regulatory Status (REACH/ECHA/CLP)\" section and on the SDS. Regulatory information — does not restrict purchase in this store.
🧮 Stoichiometry CalculatorMolGod_STOICH_1
🧪 Chemical DataMolGod_CHEMDATA_1
CAS Number
149-57-5
Molecular formula
C8H16O2
Molar mass
144.21 g/mol
IUPAC name (EN)
2-ethylhexanoic acid
SMILES
CCCCC(CC)C(=O)O
InChIKey
OBETXYAYXDNJHR-UHFFFAOYSA-N
📡 Data sourcesMolGod_SOURCES_1

The data in this widget comes from the following verified scientific sources:

  • PubChem — National Center for Biotechnology Information (NCBI/NIH), USA
  • ChEMBL — European Bioinformatics Institute (EMBL-EBI), UK
  • NIST WebBook — National Institute of Standards and Technology, USA

Data is cached locally for speed — the widget also works offline.

⚗️ Physicochemical propertiesMolGod_PHYSTAB_2
Temp. wrzenia
228.1
Density
0.9000 g/cm³ @ 20°C

Source: PubChem, NIST WebBook. Last updated: date not confirmed

🔍 External identifiersMolGod_EXTID_1
4 of 16 ID systems25%
DatabaseIdentifierActions
CAS Registry Number149-57-5Open →
PubChem CID8697[1]Open →
InChIKeyOBETXYAYXDNJHR-UHFFFAOYSA-N[1]Open →
SMILESCCCCC(CC)C(=O)O[1]

Sources: PubChem (NIH), Wikidata SPARQL, KEGG, ChEMBL (EBI), CompTox CTX (EPA).

📚 Scientific references (Chicago Author-Date) (1 sources)
  1. PubChem. National Center for Biotechnology Information (NIH/NLM), chemical compound database. ↗ dotyczy: PubChem CID · InChIKey · SMILES

Dalsza literatura

Publications thematically related to this CAS. They are not the source of any value given on this card.

Extended Bibliography (3)

  1. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Anonymous. 2017. "Investigation of (2-Ethylhexanoic acid)." Chemical Effects in Biological Systems (CEBS). https://doi.org/10.22427/ntp-data-dtxsid9025293. link [accessed: 2026-09-23] CC0 (metadata)
  2. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Lebel, Hélène. 2016. "2-Ethylhexanoic Acid." Encyclopedia of Reagents for Organic Synthesis: 1-3. https://doi.org/10.1002/047084289x.rn01903. link [accessed: 2026-09-23] CC0 (metadata)
  3. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Kim, Won-Kil, Kim, Jung-Hun, Choi, Jae-Wook. 2015. "Explosion Risk of 2-Ethylhexanoic Acid." Fire Science and Engineering 29 (6): 20-25. https://doi.org/10.7731/kifse.2015.29.6.020. link [accessed: 2026-09-23] CC0 (metadata)
📡 Spectroscopy — CAS 149-57-5MolGod_SPECHUB_MAIN
📊 Spectroscopic spectra databases — inline data 9 sources MolGod_SPECDB_2

Spectra are fetched on demand from 9 sources. Each spectrum is stored in our database — the next time it is opened there are zero requests to the external API. Download JCAMP-DX / CSV / PNG for every spectrum without searching.

IR IR (Infrared) — NIST WebBook
Public domain (US Federal)
▶ Click to load spectrum
🔗 Source
— points
📚 NIST Chemistry WebBook, SRD 69
MS (NIST) Mass Spectrum (EI) — NIST WebBook
Public domain (US Federal)
▶ Click to load spectrum
🔗 Source
— points
📚 NIST Standard Reference Database 1A
UV-Vis UV/Visible Absorption — NIST WebBook
Public domain (US Federal)
▶ Click to load spectrum
🔗 Source
— points
📚 NIST Chemistry WebBook, SRD 69
¹H NMR NMR (¹H, ¹³C) — NMRShiftDB
CC-BY-SA 4.0
▶ Click to load spectrum
🔗 Source
— points
📚 Steinbeck C et al. (2003) J. Chem. Inf. Comput. Sci. 43(1):10–16 DOI: 10.1021/ci025588g
MS (MoNA) MoNA — MassBank of North America
CC-BY 4.0
▶ Click to load spectrum
🔗 Source
— points
📚 MassBank of North America (UC Davis) DOI: 10.1002/jms.1777
IR/NMR/MS (SDBS) SDBS — Spectral Database for Organic Compounds (Japan AIST)
Free for non-commercial

Reference source — no public API. Open in an external database:

🔗 IR/NMR/MS (SDBS) →
📚 SDBSWeb: https://sdbs.db.aist.go.jp (AIST, Japan)
JP Monograph Japanese Pharmacopoeia — Monographs
Reference only

Reference source — no public API. Open in an external database:

🔗 JP Monograph →
📚 Japanese Pharmacopoeia 18th Edition (2021)
WHO INN WHO — International Nonproprietary Names
WHO Model Lists (free)

Reference source — no public API. Open in an external database:

🔗 WHO INN →
📚 WHO INN Programme
DOAJ DOAJ — Directory of Open Access Journals
OA journal index (mixed)

Reference source — no public API. Open in an external database:

🔗 DOAJ →
📚 DOAJ — doaj.org

Data is fetched once (JCAMP-DX parser) and stored in the plugin's local database. No duplicate downloads, no NIST queries on subsequent openings. Licences respected (only a deep link plus our own visualisation is published).

🔬 Interactive spectra (live — NIST / MoNA / NMRShiftDB / SDBS) (2)

Data retrieved live from multiple sources (priority chain). JCAMP-DX / CSV / PNG available for download under each spectrum.

IR — Fourier-transform infrared

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MS — Mass spectrometry (EI 70eV)

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Structural propertiesMolGod_STRUCT3D_1

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❓ Frequently asked questions (3)MolGod_FAQ_1
What is 149-57-5?
149-57-5 (CAS 149-57-5) is a chemical compound. The chemical data comes from PubChem (National Institutes of Health, USA).
Helpful?
What is the CAS number of 149-57-5?
The CAS number for 149-57-5 is 149-57-5. A CAS Registry Number is the standard identifier for a chemical substance in scientific literature and in trade.
Helpful?
How should 149-57-5 be stored?
149-57-5 should be stored as its safety data sheet directs \— typically in a dry, cool, well-ventilated place, away from heat and from materials it is incompatible with.
Helpful?
➕ Suggest a question
Download structure filesMolGod_STRDL_1

Molecular structure files from the PubChem database (NIH). Compatible with Avogadro, PyMOL, Jmol, and ChemDraw.

Source: PubChem, National Library of Medicine (NIH). CID: 8697

🔄 Concentration unit converter LIVE MolGod_UNITCONV_1

Enter the 2-Ethylhexanoic Acid concentration in any unit — the rest will be calculated automatically.

MW: 144.21 g/mol · IUPAC Gold Book ↗

⚗️ Conversion formulas + citations (per formula)
ConversionFormulaAccuracySource
% (w/v) ↔ molarityc (mol/L) = (% × 10) / MW±0.5% rel. when density ≈ 1.0 g/mLIUPAC (2019)
millimolar ↔ molarc (mol/L) = mM × 10⁻³ExactCohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007)
molarity (mol/L)c = n/V = (m/MW)/V±0.1% (depends on MW precision)IUPAC (2019)
parts per million (mg/L) ↔ molarityc (mol/L) = ppm / (1000 × MW); equivalently ppm = mg/L for dilute aqueous±1% (density-independent for dilute solutions)IUPAC (2019)
mg/mL ↔ molarityc (mol/L) = (mg/mL × 1000) / MW / 1000 = mg/mL / MW × 1±0.2%Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007)
g/L ↔ molarityc (mol/L) = (g/L) / MW±0.1% (depends on MW precision)Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007)
mmol/L ↔ molarityc (mol/L) = mmol/L × 10⁻³ExactCohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007)
Celsius ↔ KelvinT(K) = t(°C) + 273.15±0.01 K (ITS-90 scale)BIPM (Bureau International des Poids et Mesures) (2019)
Celsius ↔ FahrenheitT(°F) = T(°C) × 9/5 + 32±0.1 °FThompson A, Taylor BN (2008)
density-corrected % ↔ molarityc (mol/L) = (%w/w × ρ × 10) / MW, ρ in g/mL±0.1% when ρ known to 3 decimalsCohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007)
📚 Bibliography (8 authoritative sources)
  1. Thompson A, Taylor BN (2008). Guide for the Use of the International System of Units (SI). NIST Special Publication 811 · DOI: 10.6028/NIST.SP.811-2008
    → Primary SI standard for US scientific usage
  2. Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007). Quantities, Units and Symbols in Physical Chemistry — The IUPAC Green Book. RSC Publishing, 3rd ed. · DOI: 10.1039/9781847557889 · ISBN: 978-0-85404-433-7
    → Canonical IUPAC guide for chemistry quantities/units
  3. BIPM (Bureau International des Poids et Mesures) (2019). The International System of Units (SI), 9th edition. BIPM · ↗
    → International SI definitions (incl. redefined kilogram 2019)
  4. ISO/IEC (2022). Quantities and units — Part 1: General. International Organization for Standardization — ISO 80000-1:2022 · ↗
    → General rules for physical quantities and units
  5. ISO/IEC (2019). Quantities and units — Part 9: Physical chemistry and molecular physics. International Organization for Standardization — ISO 80000-9:2019 · ↗
    → Concentration / molality / amount-of-substance conventions
  6. Tiesinga E, Mohr PJ, Newell DB, Taylor BN (2021). CODATA recommended values of the fundamental physical constants: 2018. Rev. Mod. Phys. 93(2):025010 · DOI: 10.1103/RevModPhys.93.025010
    → Avogadro, gas constant, molar volume (2019 SI revision)
  7. IUPAC (2019). Compendium of Chemical Terminology — the IUPAC Gold Book (online). IUPAC · DOI: 10.1351/goldbook
    → Definitions of mass fraction, molality, normality, ppm, activity
  8. Mills IM, Cvitaš T, Homann K, Kallay N, Kuchitsu K (1988). Quantities, Units and Symbols in Physical Chemistry. Blackwell Scientific Publications, 1st ed. · ISBN: 0-632-01773-5
    → Historical predecessor of IUPAC Green Book
Similar molecular structuresMolGod_SIMSTR_1

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🧪 Solution Preparation Wizard WIZARD MolGod_PREP_1
① Select concentration
② Target volume
③ Solvent

Calculations per: IUPAC Gold Book ↗, Merck ↗

Computational chemistryMolGod_COMPCHEM_1

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🛡️ Safety — CAS 149-57-5MolGod_SAFEHUB_MAIN
Data limitations notice. The safety information on this page is for reference only and does not replace a full safety data sheet (SDS). Before using the product, consult the manufacturer's current safety data sheet and the GHS/CLP guidance. The CLP classification applies to the pure bulk substance, not to commercial formulations.

GHS/CLP classification — Regulation (EC) No 1272/2008 + UN GHS Rev. 9 (2021).

⚠ Warning
GHS08 — Health hazard
GHS08 Health hazard

🚨 Hazard statements (H)

  • H361 — Suspected of damaging fertility or the unborn child

🛡 Precautionary statements (P)

  • P201 — Obtain special instructions before use
  • P202 — Do not handle until all safety precautions have been read and understood
  • P280 — Wear protective gloves/protective clothing/eye protection/face protection
  • P308+P313 — IF exposed or concerned: Get medical advice/attention
  • P405 — Store locked up
  • P501 — Dispose of contents/container to an approved waste collection point

⚠ Classification based on a consensus of sources (PubChem / supplier notifications) — not verified against the harmonised classification in Annex VI (CLP). The scope of hazards may be broader than the official classification; verify against the supplier's current safety data sheet before use.

Translations: CLP Regulation (EC) 1272/2008, Annexes III and IV. Data: PubChem/NLM.

📚 Consolidated scientific references — Chicago Author-Date 10 sources

References collected from all Safety Hub tabs. CAS: 149-57-5 · PubChem ↗

  1. Parlament Europejski i Rada UE. 2008. "Rozporządzenie (WE) nr 1272/2008 w sprawie klasyfikacji, oznakowania i pakowania substancji (CLP)." Dz.Urz. UE L 353. [↗] GHS, Regulations
  2. United Nations Economic Commission for Europe (UNECE). 2021. "Globally Harmonized System of Classification and Labelling of Chemicals (GHS), Ninth Revised Edition." United Nations, Geneva. [↗] GHS
  3. Goldfrank, Lewis R., Robert S. Hoffman, Mary Ann Howland, et al.. 2019. "Goldfrank's Toxicologic Emergencies, 11th ed.." McGraw-Hill Education, New York. ISBN 978-1-25-985961-8. Pierwsza pomoc, Toksykologia
  4. National Institute for Occupational Safety and Health (NIOSH). 2023. "NIOSH Pocket Guide to Chemical Hazards (DHHS Publ. 2005-149)." U.S. Department of Health and Human Services / CDC, Cincinnati, OH. [↗] Pierwsza pomoc, PPE, Toksykologia
  5. European Committee for Standardization (CEN). 2016. "EN 374-1:2016 — Protective gloves against dangerous chemicals and micro-organisms." CEN, Brussels. [↗] PPE
  6. UNECE. 2023. "European Agreement Concerning the International Carriage of Dangerous Goods by Road (ADR 2025)." United Nations, Geneva. [↗] Utylizacja, Regulacje
  7. National Fire Protection Association (NFPA). 2022. "NFPA 400 — Hazardous Materials Code." NFPA, Quincy, MA. [↗] Magazynowanie
  8. Urben, P.G. (ed.). 2017. "Bretherick's Handbook of Reactive Chemical Hazards, 8th ed.." Butterworth-Heinemann / Elsevier, Oxford. [↗] Magazynowanie
  9. Ministerstwo Klimatu i Środowiska RP. 2023. "Baza danych o produktach i opakowaniach oraz o gospodarce odpadami (BDO)." Ministerstwo Klimatu i Środowiska, Warszawa. [↗] Utylizacja
  10. International Agency for Research on Cancer (IARC / WHO). 2024. "IARC Monographs on the Identification of Carcinogenic Hazards to Humans — List of Classifications." WHO, Lyon. [↗] Toksykologia

Tabs with their own references (Emergency, PPE, Storage, Waste) contain additional bibliographic entries within their respective sections.

📈 Analytical statistics (t-test · RSD · Grubbs · Q-Dixon) ICH Q2

Paste a series of replicate measurements (CSV, or one number per line). The calculator computes the mean, standard deviation and 95% CI, and detects outliers (Grubbs + Dixon Q).

Separator: comma, space, tab, new line. Minimum 3 measurements.
📐 Statistical formulas
  • x̄ = Σxᵢ / n — arithmetic mean
  • s² = Σ(xᵢ - x̄)² / (n-1) — sample variance
  • s = √s² — standard deviation
  • RSD% = (s / x̄) × 100% — relative standard deviation
  • CI₉₅ = x̄ ± t(0.05, n-1) × s / √n — Student's t
  • G = |xᵢ - x̄| / s — Grubbs' test
  • Q = |xsuspect - xnearest| / |xmax - xmin| — Dixon Q-test

Source: ICH Q2(R2) Validation of Analytical Procedures · ICH PDF ↗

🧪 Buffer Recipe Calculator UNIQUE
References: pKa values from Goldberg NIST 81 · CRC Handbook 100th ed. · Stoll & Blanchard 1990 (DOI)

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🧪 Solubility and solvent compatibility MolGod_SOLUB_1
Molecule
2-Ethylhexanoic Acid
Formula
C8H16O2
logP (XLogP3)
2.60
Mass (g/mol)
144.21
Polarity
Hydrophobic (non-polar)

⚠️ GC estimate (Hoftyzer–Van Krevelen). No literature HSP data for this CAS — precision ±2 MPa½. Verify experimentally.

Ra < R₀ = good miscibility · Ra < 1,5×R₀ = borderline · above = poor (R₀ — radius of the Hansen sphere of this molecule) For this molecule R₀ = 8..

Solvent Compat. Ra Visual GC-MS HPLC Applications References
Water (H₂O)2 g/L (pomiar)—
✗ NieA (aqueous) (RP)
buffercell cultureanalyticalextraction (hydrophilic)
Ethanol (EtOH)——brak podstawy✗ NieA/B modifier (RP/NP)
extractionspectroscopy (UV-Vis)synthesisHPLC modifier
Methanol (MeOH)——brak podstawy✗ NieA/B (RP) (RP)
HPLC (eluent)LC-MSKarl FischerUV-transparent to 205 nm
Acetone——brak podstawy✗ NieB modifier (NP)
GC headspacecrystallisationdegreasingsynthesis
Acetonitrile (ACN)——brak podstawy✗ NieB (RP) (RP)
HPLC eluent (gold standard)LC-MS (low UV cut-off, 190 nm)peptide analysis
DMSO——brak podstawy✗ NieN/A (N/A)
NMR (d6-DMSO)cell biology (cryopreservation)drug deliverysynthesis
THF——brak podstawy✗ NieB (NP) (NP)
GPC/SEC (polymer analysis)Grignard synthesisorganometallics
DCM (CH₂Cl₂)——brak podstawy✓ TakB (NP) (NP)
extractionNP-HPLCGC-MScrystallisation (anti-solvent)
Chloroform (CHCl₃)——brak podstawy✓ TakN/A (toxic) (N/A)
NMR (CDCl3)lipid extraction (Folch method)NP-TLC
Hexane——brak podstawy✓ TakA (NP) (NP)
NP-HPLCoil extraction (lipids)GC-MSTLC (NP)
Toluene——brak podstawy✓ TakB (NP) (NP)
NMR (d8-toluene)synthesisazeotropic drying (Dean-Stark)
📚 Scientific references for solvents (Chicago Author-Date) — click to expand

11 solvents · 54 full citations (NIST/CRC/IARC/Hansen/Reichardt/Smallwood/Wypych/Armarego/Snyder/GESTIS) — below.

Water (H₂O)
  1. NIST — NIST Chemistry WebBook — Water (CAS 7732-18-5)
  2. CRC — CRC Handbook of Chemistry and Physics, 104th ed., Sec. 8 (Properties of Water)
  3. IAPWS — IAPWS Release on Static Dielectric Constant of Water
  4. Reichardt 2011 — Solvents and Solvent Effects in Organic Chemistry
  5. GESTIS — GESTIS Substance Database — Water
Ethanol (EtOH)
  1. NIST — NIST Chemistry WebBook — Ethanol (CAS 64-17-5)
  2. CRC — CRC Handbook — Ethanol physical constants
  3. Snyder & Kirkland — Modern Liquid Chromatography — Ethanol eluotropic
  4. Smallwood — Handbook of Organic Solvent Properties — Ethanol
  5. GESTIS — GESTIS Substance Database — Ethanol
Methanol (MeOH)
  1. NIST — NIST Chemistry WebBook — Methanol (CAS 67-56-1)
  2. CRC — CRC Handbook — Methanol physical constants
  3. Snyder & Kirkland — Modern Liquid Chromatography — MeOH eluotropic, eo=0.95
  4. GESTIS — GESTIS Substance Database — Methanol
Acetone
  1. NIST — NIST Chemistry WebBook — Acetone (CAS 67-64-1)
  2. CRC — CRC Handbook — Acetone physical & thermodynamic constants
  3. Hansen 2007 — Hansen Solubility Parameters — Acetone (dD=15.5, dP=10.4, dH=7.0)
  4. Smallwood — Handbook of Organic Solvent Properties — Acetone
  5. GESTIS — GESTIS Substance Database — Acetone
Acetonitrile (ACN)
  1. NIST — NIST Chemistry WebBook — Acetonitrile (CAS 75-05-8)
  2. CRC — CRC Handbook — Acetonitrile constants
  3. Snyder & Kirkland — Modern Liquid Chromatography — ACN gold-standard HPLC eluent
  4. Reichardt 2011 — Solvents and Solvent Effects — ACN dipolar aprotic
  5. GESTIS — GESTIS Substance Database — Acetonitrile
DMSO
  1. NIST — NIST Chemistry WebBook — DMSO (CAS 67-68-5)
  2. Wypych 2019 — Handbook of Solvents Vol. 1 — DMSO comprehensive properties
  3. Hansen 2007 — HSP — DMSO (dD=18.4, dP=16.4, dH=10.2)
  4. Reichardt 2011 — Solvents and Solvent Effects — DMSO E_T(30)=45.1, dipolar aprotic
  5. GESTIS — GESTIS Substance Database — DMSO
THF
  1. NIST — NIST Chemistry WebBook — THF (CAS 109-99-9)
  2. Armarego 2009 — Purification of Laboratory Chemicals — THF drying & peroxide test
  3. Hansen 2007 — Hansen Solubility Parameters — THF (dD=16.8, dP=5.7, dH=8.0)
  4. Smallwood — Handbook of Organic Solvent Properties — THF
  5. GESTIS — GESTIS Substance Database — Tetrahydrofuran
DCM (CH₂Cl₂)
  1. NIST — NIST Chemistry WebBook — Dichloromethane (CAS 75-09-2)
  2. IARC 71 — IARC Monograph 71 — DCM (Group 2A carcinogen)
  3. Hansen 2007 — Hansen Solubility Parameters — DCM (dD=18.2, dP=6.3, dH=6.1)
  4. Reichardt 2011 — Solvents and Solvent Effects — DCM polarity index
  5. GESTIS — GESTIS Substance Database — Dichloromethane
Chloroform (CHCl₃)
  1. NIST — NIST Chemistry WebBook — Chloroform (CAS 67-66-3)
  2. IARC 73 — IARC Monograph 73 — Chloroform (Group 2B carcinogen)
  3. Hansen 2007 — Hansen Solubility Parameters — CHCl3 (dD=17.8, dP=3.1, dH=5.7)
  4. Reichardt 2011 — Solvents and Solvent Effects — CHCl3 H-bond donor strength
  5. GESTIS — GESTIS Substance Database — Chloroform
n-Hexane
  1. NIST — NIST Chemistry WebBook — n-Hexane (CAS 110-54-3)
  2. ATSDR n-Hexane — ATSDR Toxicological Profile for n-Hexane — neuropatia obwodowa (n-Heksan NIE jest kancerogenem IARC)
  3. Hansen 2007 — Hansen Solubility Parameters — n-Hexane (dD=14.9, dP=0, dH=0)
  4. Snyder & Kirkland — Modern Liquid Chromatography — n-Hexane NP standard, eo=0.00
  5. GESTIS — GESTIS Substance Database — n-Hexane
Toluene
  1. NIST — NIST Chemistry WebBook — Toluene (CAS 108-88-3)
  2. IARC 71 — IARC Monograph 71 — Toluene
  3. Hansen 2007 — Hansen Solubility Parameters — Toluene (dD=18.0, dP=1.4, dH=2.0)
  4. Smallwood — Handbook of Organic Solvent Properties — Toluene
  5. GESTIS — GESTIS Substance Database — Toluene
Solubility theory (applied in compatibility prediction):
  1. Yalkowsky, Samuel H., and Shri C. Valvani. 1980. "Solubility and Partitioning I: Solubility of Nonelectrolytes in Water." Journal of Pharmaceutical Sciences 69 (8): 912–922. https://doi.org/10.1002/jps.2600690814 — General Solubility Equation (GSE): logS = 0.5 − logP − 0.01(MP−25).
  2. Hansen, Charles M. 2007. Hansen Solubility Parameters: A User's Handbook. 2nd ed. CRC Press. https://doi.org/10.1201/9781420006834 — HSP triplet (dD, dP, dH) + Ra formula.
  3. Stefanis, E., and C. Panayiotou. 2008. "Prediction of Hansen Solubility Parameters with a New Group-Contribution Method." Int J Thermophys 29: 568–585. https://doi.org/10.1007/s10765-008-0415-z
  4. Reichardt, Christian, and Thomas Welton. 2011. Solvents and Solvent Effects in Organic Chemistry. 4th ed. Wiley-VCH. https://doi.org/10.1002/9783527632220 — E_T(30) polarity scale, solwatochromia.
  5. Snyder, Lloyd R., Joseph J. Kirkland, and John W. Dolan. 2010. Introduction to Modern Liquid Chromatography. 3rd ed. Wiley. https://doi.org/10.1002/9780470508183 — Eluotropic series, polarity index.
  6. Van Krevelen, D. W., and K. Te Nijenhuis. 2009. Properties of Polymers. 4th ed. Elsevier. https://doi.org/10.1016/B978-0-08-054819-7.X0001-5 — Hoftyzer–Van Krevelen group contribution dla dD/dP/dH z SMILES.
  7. Marcus, Yizhak. 1998. The Properties of Solvents. Wiley Series in Solution Chemistry, Vol. 4. ISBN 9780471983699 — Complete tabular set of 250+ solvents (ε, μ, donicity, acceptor numbers).
  8. PubChem Compound Database — CAS 149-57-5 lookup ↗ — logP (XLogP3), water solubility experimental + predicted.

Full bibliography in the REFERENCES accordion (at the bottom of the page) — Chicago Manual of Style 17th ed., Author-Date.

⚗️ Check reaction compatibility MolGod_RXNCOMP_1
0 0 0
Health: 0/4
Flammability: 0/4
Reactivity: 0/4
Per NFPA 704 / calculated from H-codes

Check whether 2-Ethylhexanoic Acid is compatible with another reagent

📦 Storage compatibility matrix
Acids Bases Oxidizers Flammable Toxic Gazy
Acids ✓ ✗ ✗ ✗ ⚠ ✗
Bases ✗ ✓ ⚠ ⚠ ⚠ ⚠
Oxidizers ✗ ⚠ ✓ ✗ ⚠ ✗
Flammable ✗ ⚠ ✗ ✓ ⚠ ✗
Toxic ⚠ ⚠ ⚠ ⚠ ✓ ⚠
Gazy ✗ ⚠ ✗ ✗ ⚠ ✓
✓ Can be stored together · ⚠ Caution · ✗ Do NOT store together · OSHA Chemical Segregation ↗

Compatibility data from: Bretherick's Handbook (7th ed.) ↗, GESTIS ↗, ECHA REACH ↗, NFPA 704 ↗

🧮 Laboratory calculators (8) MolGod_LABCALC_1
Dilution (C₁V₁=C₂V₂)
Molarity (M=n/V)
pH Buffer (Henderson-Hasselbalch)
Beer-Lambert (A=εcl)
Mass → Moles
Concentration % → M
ppm → mg/L
Temperature C↔F↔K

Verified formulas: IUPAC Gold Book ↗, DOI ↗

📊 Spectroscopic Databases MolGod_SPECDB_3
📋 Laboratory protocol generator MolGod_PROTOCOL_1

Protocol generated based on: GHS SDS, Aldrich Lab Guide ↗

🏷️ Label generator (QR) MolGod_LABEL_1
2-Ethylhexanoic Acid• 2-Ethylcaproic acid / Ethylhexanoic acid• IUPAC: 2-ethylhexanoic acid• CAS: 149-57-5• EC: 205-743-6• Formula: C8H16O2• Mass: 144.21 g/molWARNINGGHS HAZARD STATEMENTS:(supplier self-classification — non-binding)H361 H312 H314 H319 H360 H371 H318 H315P301+P330+P331 P301+P317 P302+P352 P302+P361+P354 P304+P340 P305+P351+P338P305+P354+P338 P308+P316 P332+P317 P337+P317 P362+P364 P316 P317 P318 P321 P363P280 P501 P405 P203 P260 P264 P264+P265 P270Anhui Eapearl Chemical Co., Ltd.12th Floor, Tongguan Number Valley, Tongling, Anhui, China+86 186 5620 1888[email protected]epchems.com
Deskryptory Lipinskiego (struktura)

Drug-likeness radar chart (Lipinski Ro5 / Veber). Green zone = compliance with criteria.

Predictive data — properties calculated in silico (SMILES/RDKit). These do not replace clinical studies. Do not use for drug evaluation without experimental verification.

MW144.2LogP2.6HBD1HBA2RotB5TPSA37.3 Ų
✓ Lipinski Ro5✓ Veber✓ Egan✗ Ghose (MW=144)✗ REOS (MW=144)✗ Lead-like Ro3 (RotB=5)
PropertyValueRating
Absorption (GI)high✓
BBB permeabilityyes (crosses)
Bioavailability (Daina 2017)
55%
CYP450 profileCYP1A2 non-inhibitorCYP2C9 non-inhibitorCYP2C19 non-inhibitorCYP2D6 non-inhibitorCYP3A4 non-inhibitor
PAINS alerts0✓
Brenk alerts0✓
pKa (pH 7.4)4.5 (predicted)
hERG (cardiotox.)✓ no
P-gp substrate—
Ames mutagenicity✓ no
DILI (hepatotox.)—
LogS (aq. solub.)—
Sources (ADMET methodology)
  1. Lipinski, Christopher A., Franco Lombardo, Beryl W. Dominy, and Paul J. Feeney. 1997. "Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings." Advanced Drug Delivery Reviews 23 (1-3): 3-25.
  2. Veber, Daniel F., Stephen R. Johnson, Hung-Yuan Cheng, et al. 2002. "Molecular properties that influence the oral bioavailability of drug candidates." Journal of Medicinal Chemistry 45 (12): 2615-2623.
  3. Daina, Antoine, Olivier Michielin, and Vincent Zoete. 2017. "SwissADME: a free web tool to evaluate pharmacokinetics, drug-likeness and medicinal chemistry friendliness." Scientific Reports 7: 42717.
  4. Egan, William J., and Gregory Lauri. 2002. "Prediction of intestinal permeability." Advanced Drug Delivery Reviews 54 (3): 273-289.
  5. Baell, Jonathan B., and Georgina A. Holloway. 2010. "New substructure filters for removal of pan assay interference compounds (PAINS) from screening libraries." Journal of Medicinal Chemistry 53 (7): 2719-2740.
  6. Brenk, Ruth, Alessandro Schipani, Daniel James, et al. 2008. "Lessons learnt from assembling screening libraries for drug discovery for neglected diseases." ChemMedChem 3 (3): 435-444.
  7. Ertl, Peter, and Ansgar Schuffenhauer. 2009. "Estimation of synthetic accessibility score of drug-like molecules based on molecular complexity and fragment contributions." Journal of Cheminformatics 1: 8.
  8. Bickerton, G. Richard, Gaia V. Paolini, Jérémy Besnard, Sorel Muresan, and Andrew L. Hopkins. 2012. "Quantifying the Chemical Beauty of Drugs." Nature Chemistry 4 (2): 90-98.
  9. Hopkins, Andrew L., and Colin R. Groom. 2002. "The Druggable Genome." Nature Reviews Drug Discovery 1 (9): 727-730.
  10. Ghose, Arup K., Vellarkad N. Viswanadhan, and John J. Wendoloski. 1999. "A Knowledge-Based Approach in Designing Combinatorial or Medicinal Chemistry Libraries for Drug Discovery." Journal of Combinatorial Chemistry 1 (1): 55-68.
  11. Tice, Raymond R., Christopher P. Austin, Robert J. Kavlock, and John R. Bucher. 2013. "Improving the Human Hazard Characterization of Chemicals: A Tox21 Update." Environmental Health Perspectives 121 (7): 756-765.
  12. Leeson, Paul D., and Brian Springthorpe. 2007. "The Influence of Drug-Like Concepts on Decision-Making in Medicinal Chemistry." Nature Reviews Drug Discovery 6 (11): 881-890.
  13. Hann, Michael M. 2011. "Molecular Obesity, Potency and Other Addictions in Drug Discovery." MedChemComm 2 (5): 349-355.
  14. Davies, Mark, Michał Nowotka, George Papadatos, et al. 2015. "ChEMBL Web Services: Streamlining Access to Drug Discovery Data and Utilities." Nucleic Acids Research 43 (W1): W612-W620.
  15. Walters, W. Patrick, and Mark A. Murcko. 2002. "Prediction of 'Drug-Likeness.'". Advanced Drug Delivery Reviews 54 (3): 255–271. https://doi.org/10.1016/S0169-409X(02)00003-0.
  16. Congreve, Miles, Robin Carr, Christopher Murray, and Harren Jhoti. 2003. "A 'Rule of Three' for Fragment-Based Lead Discovery?" Drug Discovery Today 8 (19): 876–877. https://doi.org/10.1016/S1359-6446(03)02831-9.
  17. Brenk, Ruth, Alessandro Schipani, Daniel James, Agata Krasowski, Iain Hugh Gilbert, Julie Frearson, and Paul Graham Wyatt. 2008. "Lessons Learnt from Assembling Screening Libraries for Drug Discovery for Neglected Diseases." ChemMedChem 3 (3): 435-444.
  18. Schomburg, Karen T., Sascha Bietz, Hans Briem, Andrea M. Henzler, Stefan Urbaczek, and Matthias Rarey. 2014. "Facing the Challenges of Structure-Based Target Prediction by Inverse Virtual Screening." Journal of Chemical Information and Modeling 54 (6): 1676-1686.
  19. Bemis, Guy W., and Mark A. Murcko. 1996. "The Properties of Known Drugs. 1. Molecular Frameworks." Journal of Medicinal Chemistry 39 (15): 2887-2893.
  20. Schomburg, Karen T., and Matthias Rarey. 2014. "What Is the Potential of Structure-Based Target Prediction Methods?" Future Medicinal Chemistry 6 (17): 1987-1989.
  21. Obringer C, Lester C, Karb M et al.. (2023). "Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situation.". Regulatory toxicology and pharmacology : RTP. https://doi.org/10.1016/j.yrtph.2022.105315
  22. French KJ, Strickler MD, Rock DA et al.. (2001). "Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.". Biochemistry. https://doi.org/10.1021/bi010063+
  23. Juberg DR, David RM, Katz GV et al.. (1998). "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.". Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. https://doi.org/10.1016/s0278-6915(97)00168-3
  24. Bui LM, Taubeneck MW, Commisso JF et al.. (1998). "Altered zinc metabolism contributes to the developmental toxicity of 2-ethylhexanoic acid, 2-ethylhexanol and valproic acid.". Toxicology. https://doi.org/10.1016/s0300-483x(97)00171-6
  25. Plonait SL, Nau H, Maier RF et al.. (1993). "Exposure of newborn infants to di-(2-ethylhexyl)-phthalate and 2-ethylhexanoic acid following exchange transfusion with polyvinylchloride catheters.". Transfusion. https://doi.org/10.1046/j.1537-2995.1993.33793325058.x
  26. Pennanen S, Manninen A. (1991). "Distribution of 2-ethylhexanoic acid in mice and rats after an intraperitoneal injection.". Pharmacology & toxicology. https://doi.org/10.1111/j.1600-0773.1991.tb01208.x
  27. Ritter EJ, Scott WJ Jr, Randall JL et al.. (1987). "Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.". Teratology. https://doi.org/10.1002/tera.1420350107
  28. Obringer C, Lester C, Karb M et al. 2023. "Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situation." Regulatory toxicology and pharmacology : RTP. DOI: 10.1016/j.yrtph.2022.105315. [DOI ↗]
  29. Walker V, Mills GA. 2001. "Urine 4-heptanone: a beta-oxidation product of 2-ethylhexanoic acid from plasticisers." Clinica chimica acta; international journal of clinical chemistry. DOI: 10.1016/s0009-8981(01)00390-4. [DOI ↗]
  30. Juberg DR, David RM, Katz GV et al. 1998. "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse." Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. DOI: 10.1016/s0278-6915(97)00168-3. [DOI ↗]
  31. Hamdoune M, Duclos S, Mounie J et al. 1995. "In vitro glucuronidation of peroxisomal proliferators: 2-ethylhexanoic acid enantiomers and their structural analogs." Toxicology and applied pharmacology. DOI: 10.1006/taap.1995.1066. [DOI ↗]
  32. Górski T, Goehl TJ, Jameson CW et al. 1990. "Gas chromatographic determination of 2-ethylhexanol and 2-ethylhexanoic acid as derivatives suitable for electron-capture and nitrogen-phosphorus detection after single reaction with heptafluorobutyrylimidazole." Journal of chromatography. DOI: 10.1016/s0021-9673(01)93096-1. [DOI ↗]
  33. Kunstmann, Babette; Kohns, Maximilian; Hasse, Hans. 2024. "Thermophysical Properties of Mixtures of 2-Ethylhexanoic Acid and Ethanol." DOI: 10.31224/3443. [DOI ↗]
  34. Wisniak, Jaime; Mejía, Andrés. 2020. "Comment on “Isobaric Vapor + Liquid Equilibrium Measurements and Calculations for Using Nontraditional Models for the Association Systems of Ethyl Acetate + 2-Ethylhexanoic Acid and Propyl Acetate + 2-Ethylhexanoic Acid at Atmospheric Pressure”." Journal of Chemical & Engineering Data. DOI: 10.1021/acs.jced.0c00661. [DOI ↗]
  35. 2017. "Investigation of (2-Ethylhexanoic acid)." Chemical Effects in Biological Systems (CEBS). DOI: 10.22427/ntp-data-dtxsid9025293. [DOI ↗]
  36. Anonymous. 2017. "Investigation of (2-Ethylhexanoic acid)." Chemical Effects in Biological Systems (CEBS). https://doi.org/10.22427/ntp-data-dtxsid9025293. [DOI ↗]
  37. Lebel, Hélène. 2016. "2-Ethylhexanoic Acid." Encyclopedia of Reagents for Organic Synthesis. DOI: 10.1002/047084289x.rn01903. [DOI ↗]
  38. Lebel, Hélène. 2016. "2-Ethylhexanoic Acid." Encyclopedia of Reagents for Organic Synthesis: 1-3. https://doi.org/10.1002/047084289x.rn01903. [DOI ↗]
  39. Kim, Won-Kil; Kim, Jung-Hun; Choi, Jae-Wook. 2015. "Explosion Risk of 2-Ethylhexanoic Acid." Fire Science and Engineering. DOI: 10.7731/kifse.2015.29.6.020. [DOI ↗]
  40. Kim, Won-Kil, Kim, Jung-Hun, Choi, Jae-Wook. 2015. "Explosion Risk of 2-Ethylhexanoic Acid." Fire Science and Engineering 29 (6): 20-25. https://doi.org/10.7731/kifse.2015.29.6.020. [DOI ↗]
  41. Sumida K, Kaneko H, Yoshitake A. 1996. "Inhibition of animal acetyl-coenzyme A carboxylase by 2-(p-chlorophenoxy)-2-methylpropionic acid and 2-ethylhexanoic acid." Chemosphere. DOI: 10.1016/0045-6535(96)00331-1. [DOI ↗]
  42. Bolton, Evan E., Yanli Wang, Paul A. Thiessen, and Stephen H. Bryant. 2008. "PubChem: Integrated Platform of Small Molecules and Biological Activities." Annual Reports in Computational Chemistry 4: 217-241. [DOI ↗]
  43. Kim, Sunghwan, Jie Chen, Tiejun Cheng, et al. 2023. "PubChem 2023 update." Nucleic Acids Research 51 (D1): D1373-D1380. [DOI ↗]
  44. Kim, Sunghwan, Tiejun Cheng, Jianyong He, Chen Cheng, et al. 2021. "PubChem Protein, Pathway, Reaction, and Disease Specifications." Journal of Cheminformatics 13: 16. [DOI ↗]
  45. Hähnke, Volker D., Sunghwan Kim, and Evan E. Bolton. 2018. "PubChem chemical structure standardization." Journal of Cheminformatics 10: 36. [DOI ↗]
  46. Wang, Yanli, Stephen H. Bryant, Tiejun Cheng, Jiyao Wang, et al. 2017. "PubChem BioAssay: 2017 update." Nucleic Acids Research 45 (D1): D955-D963. [DOI ↗]
  47. Cheng, Tiejun, et al. 2014. "Computation of Octanol-Water Partition Coefficients by Guiding an Additive Model with Knowledge." Journal of Chemical Information and Modeling 54 (3): 793-805. [DOI ↗]
  48. 2007. "(r)‐2‐ethylhexanoic Acid Sodium Salt." Hawley's Condensed Chemical Dictionary. DOI: 10.1002/9780470114735.hawley06895. [DOI ↗]
  49. Anonymous. 2007. "(r)‐2‐ethylhexanoic Acid Sodium Salt." Hawley's Condensed Chemical Dictionary: 533-533. https://doi.org/10.1002/9780470114735.hawley06895. [DOI ↗]
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  56. Patent CN-105999373-A. Indexed in PubChem CID 8697. ↗
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🧪 Solution preparation assistant (Smart Prep) MolGod_PREP_2

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📚 Scientific literature overview — CAS 149-57-5MolGod_LITHUB_MAIN
⭐ Key findings (scientific literature) 7 publications
🏆 CAS 149-57-5 — multi-criteria ranking (W12): 30% citations · 20% recency · 20% topic · 15% historical · 15% open access.
  1. #1
    Beatrice Lopez; Fabrice Guillet; Solenne Martin; Christophe Chesne; Pierre Jaques Ferret (2018) · Drug Metabolism and Pharmacokinetics
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 5.45 Pharmacology DOI ↗
  2. #2
    Obringer C, Lester C, Karb M et al. (2023) · Regulatory toxicology and pharmacology : RTP
    Why it matters: Recent (2023)
    SCORE 4.7 Mechanism DOI ↗ PubMed ↗
  3. #3
    Walker V, Mills GA (2001) · Clinica chimica acta; international journal of clinical chemistry
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 0.8 Mechanism DOI ↗ PubMed ↗
  4. #4
    Górski T, Goehl TJ, Jameson CW et al. (1990) · Journal of chromatography
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 0.8 Mechanism DOI ↗ PubMed ↗
  5. #5
    Sumida K, Kaneko H, Yoshitake A (1996) · Chemosphere
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 0 Mechanism DOI ↗ PubMed ↗
  6. #6
    Juberg DR, David RM, Katz GV et al. (1998) · Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 0 Pharmacology DOI ↗ PubMed ↗
  7. #7
    Hamdoune M, Duclos S, Mounie J et al. (1995) · Toxicology and applied pharmacology
    Why it matters: Selected by multi-criteria score (citations + recency + topic + historical + OA).
    SCORE 0 Mechanism DOI ↗ PubMed ↗
🔬 HPLC — methods & parameters — CAS 149-57-5MolGod_HPLCHUB_MAIN
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Gradient based on PubChem XLogP3 + LSS (Snyder et al. 2010, ch. 9).

  • Column: C18
  • Buffer: phosphate
  • Flow: 1 mL/min
  • logP: 2.6 (PubChem XLogP3)
  • Ramp: 26% → 95% B, 15 min
  • Total analysis time: 28 min
t (min) %A %B flow (mL/min) Comment
0 74 26 1 start (equilibrium)
2 74 26 1 end of initial hold
17 5 95 1 end of LSS ramp
22 5 95 1 column wash
23 74 26 1 return to init
28 74 26 1 re-equilibration
📚 Scientific references (Chicago Author-Date)
  1. Snyder, Lloyd R., John W. Dolan, and Joseph J. Kirkland. 2010. Introduction to Modern Liquid Chromatography. Wiley. — Chapter 9 — gradient elution, LSS theory (cited as Snyder et al. 2010 in tool description).
  2. Schoenmakers, Peter J. 1986. Optimization of Chromatographic Selectivity: A Guide to Method Development. Elsevier. — Numerical optimization of gradient programs.
  3. Snyder, L. R., and J. W. Dolan. 2007. High-Performance Gradient Elution: The Practical Application of the Linear-Solvent-Strength Model. Wiley. — Foundational LSS reference for the %B_init = 5 + 8·logP heuristic implemented here.
  4. Nikitas, Pavlos, and Adrian Pappa-Louisi. 2009. "Retention models for isocratic and gradient elution in reversed-phase liquid chromatography." Journal of Chromatography A 1216: 1737-1755. [DOI ↗] — Modern review of gradient retention models — basis for non-LSS extensions.
  5. Carr, Peter W.. 2009. "The new physical chemistry of HPLC." Journal of Chromatography A 1216: 1764-1772. [DOI ↗]
  6. Dong, Michael W. 2019. HPLC and UHPLC for Practicing Scientists. Wiley. https://doi.org/10.1002/9781119313793. — Modern UHPLC gradient programming, sub-2 µm scaling rules.
  7. Wu, Naijun, and Anton M. Clausen. 2007. "Fundamental and practical aspects of ultrahigh pressure liquid chromatography for fast separations." Journal of Separation Science 30: 1167-1182. [DOI ↗]
  8. Stoll, Dwight R., and Peter W. Carr. 2017. "Two-Dimensional Liquid Chromatography: A State of the Art Tutorial." Analytical Chemistry 89: 519-531. [DOI ↗] — Reference for orthogonal gradient design (2D-LC second dimension).
  9. Dolan, John W.. 2013. "When to Modify Method Conditions." LCGC North America 31: 192-199.
  10. Meyer, Veronika R. 2010. Practical High-Performance Liquid Chromatography. Wiley. — Chapter 7 — practical gradient design with isokratyczny scouting.

REST: /wp-json/molgod/v1/hplc/gradient/149-57-5

📐 Column dimensions — van Deemter calculator N=12,466

Formula: H = A + B/u + C·u (Van Deemter et al. 1956), N = L/H, ΔP ≈ η·L·u / (K_p·dp²) (Knox 1977). u_opt = √(B/C) (Giddings 1965).

Dimensions150 × 4.6 mm, 5 µm
Theoretical plates (N)12,466
N at u_opt12,500
HETP (current)12.032 µm
Min. HETP12 µm
Linear velocity (u)0.1003 cm/s
u_opt (van Deemter)0.12 cm/s
Back pressure (ΔP)42.1 bar
Analysis time (dead volume)2.49 min
📚 Scientific references (Chicago Author-Date)
  1. Van Deemter, J. J., F. J. Zuiderweg, and A. Klinkenberg. 1956. "Longitudinal diffusion and resistance to mass transfer as causes of nonideality in chromatography." Chemical Engineering Science 5: 271-289. https://doi.org/10.1016/0009-2509(56)80003-1 — Original van Deemter equation paper — basis of H = A + B/u + C·u in this calculator.
  2. Giddings, J. Calvin. 1965. "Dynamics of Chromatography, Part I: Principles and Theory.". Marcel Dekker. — Theoretical underpinning of HETP minimum and u_opt = sqrt(B/C).
  3. Poppe, Hans. 1997. "Some reflections on speed and efficiency of modern chromatographic methods." Journal of Chromatography A 778: 3-21. https://doi.org/10.1016/S0021-9673(97)00376-2 — Speed-efficiency Pareto plot — context for sub-2 µm UHPLC scaling.
  4. Wu, Naijun, and Anton M. Clausen. 2007. "Fundamental and practical aspects of ultrahigh pressure liquid chromatography for fast separations." Journal of Separation Science 30: 1167-1182. https://doi.org/10.1002/jssc.200700026 — UHPLC pressure scaling — extends Darcy ΔP formula to sub-2 µm particles.
  5. Carr, Peter W.. 2009. "The new physical chemistry of HPLC." Journal of Chromatography A 1216: 1764-1772. https://doi.org/10.1016/j.chroma.2008.11.094 — Modern reinterpretation of A, B, C terms (eddy diffusion vs. b-term).
  6. Knox, John H.. 1977. "Practical aspects of LC theory." Journal of Chromatographic Science 15: 352-364. https://doi.org/10.1093/chromsci/15.9.352 — Reduced plate height equation h = a·v^(1/3) + b/v + c·v.
  7. Dong, Michael W.. 2019. "HPLC and UHPLC for Practicing Scientists.". Wiley (2nd ed.). https://doi.org/10.1002/9781119313793 — Practical N targets vs particle size table (UHPLC method scaling).
  8. Snyder, L. R., J. J. Kirkland, and J. L. Glajch. 1997. "Practical HPLC Method Development.". Wiley (2nd ed.). — Column dimensioning rules of thumb (L, dp, dc) for given α and N.
  9. Engelhardt, Heinz. 2014. "100 Years of Chromatography.". Wiley-VCH (2nd ed.).
  10. Meyer, Veronika R.. 2010. "Practical High-Performance Liquid Chromatography.". Wiley (5th ed.).

REST: /wp-json/molgod/v1/hplc/column/149-57-5

🧪 Mobile phase — compatibility matrix MISCIBLE
Component Name UV cutoff (nm) P' Detectors
Solv. Acetonitrile (MeCN) 190 5.8 UV, MS, ELSD, RID, FLD
Solv. Water 190 10.2 UV, MS, ELSD, RID, FLD
Buffer Phosphate (KH2PO4 / K2HPO4) 195 pH 2.0-3.0 / 6.5-8.0 / 11.0-12.5 MS ✗

Detector: UV — compatible with both solvents.

📚 Scientific references (Chicago Author-Date)
  1. Sadek, Paul C.. 2002. "The HPLC Solvent Guide.". Wiley-Interscience (2nd ed.).
  2. Snyder, L. R.. 1978. "Classification of the solvent properties of common liquids." Journal of Chromatographic Science 16: 223-234. https://doi.org/10.1093/chromsci/16.6.223
  3. Reichardt, Christian, and Thomas Welton. 2010. "Solvents and Solvent Effects in Organic Chemistry.". Wiley-VCH (4th ed.).
  4. Vailaya, Anant, and Csaba Horváth. 1998. "Retention thermodynamics in hydrophobic interaction chromatography." Industrial & Engineering Chemistry Research 37: 4040-4055. https://doi.org/10.1021/ie980212h
  5. Krstulović, Andrea M., and Phyllis R. Brown. 1981. "Reversed-phase High-Performance Liquid Chromatography.". Wiley.
  6. Snyder, L. R., J. J. Kirkland, and J. L. Glajch. 1997. "Practical HPLC Method Development.". Wiley (2nd ed.).
  7. Carr, Peter W.. 2009. "The new physical chemistry of HPLC." Journal of Chromatography A 1216: 1764-1772. https://doi.org/10.1016/j.chroma.2008.11.094
  8. Boysen, Reinhard I., and Milton T. W. Hearn. 2009. "Multi-modal HPLC of proteins." Journal of Chromatographic Science 47: 645-654. https://doi.org/10.1093/chromsci/47.8.645
  9. Dong, Michael W.. 2019. "HPLC and UHPLC for Practicing Scientists.". Wiley (2nd ed.). https://doi.org/10.1002/9781119313793
  10. Meyer, Veronika R.. 2010. "Practical High-Performance Liquid Chromatography.". Wiley (5th ed.).

REST: /wp-json/molgod/v1/hplc/mobile-phase?solvent_a=...&solvent_b=...

Complete HPLC Method Guide Peer-Reviewed

Molecule-specific scenarios, troubleshooting, and literature references

Molecular Predictor

Predicted parameters for this molecule (CAS 149-57-5) are based on literature-backed models (Snyder-Dolan LSS, Neue pore-size rules).

Retention Time
7.7 min
Range: 5.39 – 10.01
confidence: medium
Model: Snyder-Dolan LSS na kolumnie C18 150×4.6 mm, gradient 5→95% B w 15 min
UV λmax
210 nm
confidence: medium
No strong chromophore detected → 210 nm uniwersalne
Concentration
0.5 mg/mL
= 3.467 mM
confidence: high
Safe linear range detektora UV (nie przekroczy 1.5 AU)
Buffer pH
2
Range: 1.5 – 2.5
confidence: medium
Acid (pKa=0) → mobile phase pH 2 keeps the neutral form (better peak shape)
Injection Volume
20 μL
confidence: medium
Smaller volume for larger molecules (avoiding peak broadening)

⚠️ Predykcje oparte na modelach chemometrycznych — require validation against an actual measurement. Confidence: low/medium/high depending on the available descriptors.

Real Chemist Problem

Eksport chromatogramu do raportu

Your boss wants a PNG of the chromatogram for a presentation. You only have ChemStation with a .ch file. How to get from .ch → PNG?

How We Solve This

1

Exact Solvent List

Name + CAS + Grade + Role in method

2

Grade Explanations

HPLC vs LC-MS vs Far UV — when to use which

3

Consumption Calculator

4

Shopping List

One-click add to cart

Interactive Calculator

Deep Education

Understanding Mobile Phase Chemistry

Why Acetonitrile vs Methanol?
PropertyAcetonitrile (ACN)Methanol (MeOH)
Viscosity (20°C)0.37 cP0.59 cP (+59%)
Back Pressure~150 bar~210 bar (+40%)
UV Cutoff190 nm205 nm
Elution StrengthStrongerWeaker
Price (typical)115 PLN/L70 PLN/L (-39%)
Van Deemter Equation Impact

H = A + B/u + Cu

Higher viscosity (MeOH) → lower optimal flow rate → longer runtime.

Buffer Selection: Why NH₄HCO₃?
  • Volatile: MS-compatible (evaporates without residue)
  • pH range: 6.5–8.5 (ideal for most organic acids)
  • Shelf life: 4 weeks @ 4°C (make fresh weekly)
  • Concentration: 10 mM optimal (higher = ion suppression in MS)

Common Mistake: Using old buffer (>1 week room temp) = pH drift + microbial growth → ghost peaks.

Cost Savings Calculator

How much you save by using naszej metody zamiast alternatyw? Kwartalne koszty labu HPLC.

1. Solwenty — ACN vs MeOH

—
Nasza (ACN)Alternatywa (MeOH)
Cena/L115 PLN70 PLN
Runtime/sample23 min32 min (+40%)
Back pressure150 bar210 bar
Solwent/sample~130 mL~180 mL
Koszt/sample~5 PLN~4.5 PLN
Czas/sample23 min32 min
Czas pracy chemika——
Total/quarter——

2. Kolumna — z guard vs bez

—
Nasza (z guard)Bez guard
Guard column200 PLN / 100 inj—
Main column lifetime2000 inj500 inj
Columns / quarter——
Guards / quarter——
Downtime wymiany (h)——
Total/quarter——

3. Method development — SOP vs scratch

—
Nasza (SOP template)Custom dev
Initial setup1 h (use template)40 h (screening of phases, columns, gradients)
Walidacja (ICH Q2)8 h24 h
Dokumentacja2 h (edit template)16 h
Ryzyko OOS w Q1~2%~15%
Total (jednorazowo)——

4. Fast gradient (high-throughput) — ROI

—
Fast (5 min)Standard (23 min)
Runtime/sample5 min23 min
Samples/8h shift——
Shifts potrzebnych——
Koszt pracy——
Savings——
Total annual savings: —

Frequently Asked Questions

NIE dla LC-MS (sole w wodzie dest. → piki duchów). OK dla UV-HPLC tylko jeśli filtrujesz 0.22 μm. Bezpiecznie: HPLC grade 9 zł/L.

Source: ResearchGate

0.79 g NH₄HCO₃ (MW 79.06). Dissolve in 900 mL, make up to 1000 mL, check pH = 7.0±0.2.

Source: r/chemistry

ACN: niższa lepkość (mniejsze ciśnienie), UV cutoff 190 nm. MeOH: 40% tańszy, ale wyższe ciśnienie +50 bar i UV cutoff 205 nm. Dla gradientu: ACN preferowany.

Source: Chromatography Forum

Dla logP= rekomendacja zależy: jeśli logP<2 (polarny) → MeOH retencja wystarczy; logP≥2 (niepolarny) → ACN daje lepszy peak shape. Dla tej molekuły (MW=144.21, CAS 149-57-5) zaczynaj od ACN w gradiencie 5→95% B.

Source: Snyder LSS Model

Gradient Problem From The Lab

Ghost peaks w ostatnim dniu stability

Day 90 stability pull. 6 batch × 2 repeats. W próbce widzę duplikaty peaków z poprzedniego dnia. OOS opened. 4 dni investigation. Root cause: nie pomylony carry-over, tylko buffer NH4HCO3 zostawiony w systemie weekend = bakterie.
Lesson learned (Dr. Tomasz W., PhD pharmaceutical, 2024-08-22):
NIGDY nie zostawiaj buforu w systemie >3 dni. Zawsze flush z 80% ACN/20% H2O przed weekendem. Koszt lekcji: 4 dni pracy + 3 batch release delay.

Our Gradient Strategy

  • Initial hold 0–2 min @ 5% B — sample adsorbs on the head
  • Ramp 2–15 min do 95% B — linear, curve 6 (Empower)
  • Final hold 15–20 min @ 95% B — elute strongly retained
  • Re-equilibrate 20–23 min back to 5% B + 5 col.volumes

Gradient Visualizer

Gradient Timeline

#Time%B start%B endDurationSlope (Δ%B/min)Step

Slope & Dwell Volume Test

—
Slope (Δ%B/min)
—
Gradient volume (mL)
—
Dwell vol estimate (mL)
—
k*·t0 (dla Rs)

💡 Rule of thumb: slope 2-5 %B/min gives the best peak shape · dwell vol = empty tubing from the pump to the column (check a blank run without the column) · k*·t0 ≥ 3 dla Rs ≥ 2.0.

Snyder-Dolan LSS Model

Log k = log kw − S·φ, gdzie φ = fraction B. Optymalny gradient: Δφ ≈ 0.6–0.8 per 5 t0. Dla kolumny 250×4.6mm @ 1 mL/min → t0 ≈ 2 min → gradient 10–12 min.

Frequently Asked Questions

Linear = płynne odklejanie związku od kolumny = lepszy peak shape (Tf < 1.3). Step gradient daje shock waves = artifacts.

Source: Snyder Seminar

Heurystyka Snyder: Rt ≈ 2.5·logP + 1.2 min. Dla 2-ethylhexanoic acid (logP=) → szacunkowe Rt=— min. ±30% wariancja zależnie od dead volume i gradient slope. Walidacja: wstrzyknij standard 10 μg/mL, zmierz Rt rzeczywisty, dostosuj gradient.

Source: Predictive modeling

Heurystyka Snydera: start%B = (logP - 1) × 10. Dla logP=2 → start 10% B. Zawsze z 2 min isocratic hold aby pozwolić próbce zaadsorbować.

Source: LCGC

Column Choice Dilemma

First column connection — no leak

A C18 100×4.6 mm column straight out of the box. How to connect it without dismantling it and spilling ACN over the autosampler?

Recommended Columns

A

Zorbax Eclipse Plus C18

150×4.6 mm · 3.5 μm · pH 2–9

B

Waters XBridge C18

150×4.6 mm · 3.5 μm · pH 1–12 (high pH)

C

Phenomenex Kinetex C18

100×4.6 mm · 2.6 μm core-shell · fast

Column Lifetime Rules

  • Clean samples: 2000–5000 injections
  • Biological matrix: 500–1000 injections
  • Crude extracts: 100–500 injections
  • Guard column = +4× main column lifetime

Frequently Asked Questions

C18 (18 węgli, bardziej lipofilowa) dla logP 0-5. C8 (8 węgli) dla bardzo polarnych (logP <0). C4 dla białek. Twój związek logP~2 → C18.

Source: Phenomenex Knowledge

Mała kolumnka (2cm) PRZED główną. Łapie zanieczyszczenia. Koszt 200 PLN, wymiana co 100 wstrzyknięć. Oszczędność: 1600 PLN na lifetime głównej kolumny.

Source: Agilent App Notes

Rule of thumb: analyty MW10000 (białka) → pore 1000 Å. Dla MW=144.21 (CAS 149-57-5) użyj standardowej kolumny C18 100 Å.

Source: Phenomenex Guide

Detection Gotcha

Why am I not seeing any peaks?

You injected the sample, you wait 23 min and... a flat line. Anxiety is rising.
Lesson learned (Student MSc, UW, 2024-10):
Wavelength 254 nm does not work for most carboxylic acids — use 210 nm.

DAD Settings

ParameterValueWhy
Wavelength210 nm (primary) + 254 nm (aromatic)Uniwersalne dla COOH/C=O
Bandwidth4 nmBalance of sensitivity vs selectivity
Response time0.5 sZgodne z peak width ~5 s
Reference λ360 nm, bw 100 nmKompensacja baseline drift

Alternative Detectors

  • RID — for compounds without UV absorbance (sugars, polymers). Sensitivity x1000 lower.
  • ELSD — uniwersalny, ale destroys sample (niezgodny z MS).
  • LC-MS/MS — LOD 1 pg, strukturalna potwierdzenie via MRM.
  • CAD — charged aerosol, lepsze od ELSD dla lipid/polar.

Validation Reality Check

OOS investigation — 1 batch fail per spec

Assay 97.5% (spec 98-102%). OOS opened. Within 24h you must determine: root cause (sample / method / system). How?

USP <621> + ICH Q2(R1) Criteria

ParameterAcceptanceFormula
Resolution (Rs)≥ 2.02(tR2 − tR1) / (w1 + w2)
Tailing factor (Tf)≤ 1.5W0.05 / (2·f)
Plates (N)≥ 500016·(tR / w)²
RSD (6 injections)≤ 2.0%σ / μ × 100%
Linearity (R²)≥ 0.999080–120% spec, 5 levels

Pre-Flight SST Checklist

  • Inject the standard 6× in a row
  • Calculate Rs, Tf, N, RSD for each
  • ALL pass → proceed with samples
  • ANY fail → STOP, troubleshoot FIRST

Regulatory Compliance

The method was designed in accordance with the regulations below. Click a badge to see compliance details.

USP <621> Chromatography Compliant

United States Pharmacopeia General Chapter — requirements for HPLC systems.

  • Resolution (Rs) &geq; 2.0
  • Tailing factor (Tf) &leq; 2.0
  • Theoretical plates (N) &geq; 2000
  • Relative standard deviation (RSD) &leq; 2.0% (6 replicates)

Reference: USP-NF 2024, General Chapter <621> Chromatography

ICH Q2(R1) Method Validation Compliant

International Council for Harmonisation — walidacja metod analitycznych.

  • Specificity — baseline separation of all analytes
  • Linearity — R² &geq; 0.9990, 5 levels (80–120% of spec)
  • Accuracy — 98–102% recovery
  • Precision — RSD &leq; 2.0% (repeatability), &leq; 3.0% (intermediate)
  • Robustness — DoE across 5 factors (flow ±10%, temp ±5°C, pH ±0.2, %B ±2%, λ ±2 nm)

Reference: ICH Q2(R1) Validation of Analytical Procedures, 2005

EP 2.2.46 European Pharmacopoeia Compliant

European Pharmacopoeia — chromatographic separation techniques.

  • Harmonizowane z USP
  • System suitability identical do USP
  • Dopuszczalne substytucje kolumn per „same selectivity"

Reference: EP 11.0, Chapter 2.2.46

JP 2.00 Japanese Pharmacopoeia Compliant

Japanese Pharmacopoeia — aligned with USP/EP harmonisation after 2020.

  • Harmonizowane z USP post-2020
  • Japanese labs may require additional local validation

Reference: JP 18th Edition, General Chapter 2.00

FDA 21 CFR 211 cGMP Compliant

Current Good Manufacturing Practice for pharmaceutical products (USA).

  • §211.22 — QC unit responsibilities
  • §211.160 — laboratory controls
  • §211.165 — testing and release
  • §211.194 — laboratory records (complete + audit trail)
  • Data integrity per ALCOA+

Reference: 21 CFR Part 211 — Current Good Manufacturing Practice

ISO 17025 Testing Labs Aligned

International standard for the competence of testing laboratories.

  • Method validation per ISO 17025 §7.2
  • Measurement uncertainty udokumentowana
  • Traceability to SI units

Reference: ISO/IEC 17025:2017

Method Comparison Matrix

Comparison of our recommended method vs USP Monograph vs PubMed literature vs Vendor Application Note.

Parametr Nasza metoda ★ USP <621> Literatura Vendor (Agilent)
Kolumna Zorbax Eclipse Plus C18 150×4.6 mm L1 (C18, bonded, 5 μm) n/a (brak PubMed refs dla tego CAS) Zorbax SB-C18 150×4.6 mm
Particle size 3.5 μm 5 μm (USP default) — 5 μm
Faza A 10 mM NH₄HCO₃ pH 7.0 Phosphate buffer pH 2.5 — 0.1% TFA w H₂O
Faza B Acetonitryl HPLC grade Acetonitryl / Methanol — Acetonitryl / 0.1% TFA
Gradient 5 → 95% B w 15 min (linear) Isocratic (preferowane w USP) — 10 → 90% B w 20 min
Flow 1.0 mL/min 1.5 mL/min — 1.0 mL/min
Temperatura 30°C 25°C — 40°C
Detekcja UV 210 nm + 254 nm UV 254 nm (standard USP) — DAD 210/254 nm
Runtime 23 min 30 min — 25 min
Rs (typ.) 2.3 ≥ 2.0 — 2.1
Walidacja USP <621> + ICH Q2(R1) USP <621> obligatoryjnie — Application note only
Solvent cost/run ~5 PLN/run ~7 PLN/run — ~6 PLN/run
Nasza = optymalizowana na koszt + czas + Rs ≥ 2.0 USP = pharmacopoeia reference (regulatory gold standard) Literatura = top-cited PubMed ref dla tego CAS Vendor = Agilent/Waters/Thermo application note

Interactive Troubleshooting Tree

Pick a symptom → see the most likely causes → click to see the fix.

Temperatura kolumny niestabilna 55%

Diagnoza: Column oven on? 30°C?

Fix: Turn the column thermostat on to 30°C.

⏰ 5 min warm-up ✓ 90% success rate
Wrong wavelength (254 nm vs 210 nm) 40%

Diagnoza: Method → DAD → Primary λ — check whether it is 210

Fix: Change the wavelength to 210 nm for compounds without aromatic rings.

⏰ 2 min ✓ 90% success rate
UV lamp not switched on 35%

Diagnoza: Status lampki na detektorze — zielona?

Fix: Turn on the lamp, wait 3-5 min for warm-up.

⏰ 5 min ✓ 95% success rate
Sample concentration too low 20%

Diagnoza: Is the sample >0.1 mg/mL?

Fix: Increase the concentration 10× to 1 mg/mL.

⏰ 10 min ✓ 85% success rate
Column clogged with particles 70%

Diagnoza: Do you filter samples through 0.22 μm?

Fix: Replace the column frit OR the guard column. In future, filter every sample.

⏰ 15 min 💵 200 PLN ✓ 75% success rate
Gradient za szybki 60%

Diagnoza: Jaki slope %B/min?

Fix: Zwolnij gradient: 13→56% B w 20 min zamiast 15 min.

✓ 80% success rate
Flow za wysoki 25%

Diagnoza: Flow 1.5 mL/min?

Fix: Zmniejsz do 0.8 mL/min.

✓ 70% success rate
Incorrect buffer pH 70%

Diagnoza: Zmierz pH bufora — 7.0±0.2?

Fix: Make fresh buffer 10 mM NH₄HCO₃ pH 7.0.

⏰ 15 min 💵 10 PLN ✓ 85% success rate
Column worn out 20%

Diagnoza: Number of injections? >2000?

Fix: Regeneruj: flush 100% ACN 30 min, potem 100% MeOH 30 min.

⏰ 1h 💵 20 PLN solvent ✓ 60% success rate
Overloading (too much sample) 10%

Diagnoza: Fronting + tailing at the same time? Concentration >5 mg/mL?

Fix: Reduce inj. vol 10→5 μL or dilute 2×.

⏰ 5 min ✓ 90% success rate

Frequently Asked Questions

6× wstrzyknięcie standardu PRZED próbkami. Mierzysz Rs, Tf, RSD, N. Wszystkie muszą być PASS — inaczej nie analizuj. Kryteria: USP .

Source: USP Online

Dla API (active pharmaceutical ingredient) typowo 98-102% label claim. Dla 2-ethylhexanoic acid (CAS 149-57-5) sprawdź: (1) USP monograph jeśli istnieje, (2) kompendium pharmacopoeia wewnętrzna, (3) ICH Q6A dla specyfikacji nowych substancji. Related substances ≤0.10% per ICH Q3A.

Source: ICH Q6A

USP : Rs ≥ 2.0. Fix: (1) wolniejszy gradient +30%, (2) niższy flow 0.8 mL/min, (3) dłuższa kolumna 250mm, (4) niższa temp 20°C.

Source: FDA Guidance

Prep Mistakes That Ruined The Run

Why does my chromatogram look like a cardiogram?

The baseline jumps ±10 mAU, you see peaks but also „humps" between them. Integration is impossible.

Sample Prep Protocol

  1. Dissolve 10 mg of sample in 10 mL of mobile phase (initial composition)
  2. Sonikuj 5 min → vortex 30 s
  3. Filtruj 0.22 μm PTFE (nie PVDF — adsorbuje!)
  4. Transfer 1 mL do HPLC vial z septum PTFE/silikon
  5. Przechowuj 4°C max 48h

Why Filter 0.22 μm?

Particles >0.22 μm clog the column inlet frit. Pressure rises +50 bar per 100 injections. Column lifetime drops from 2000 to 500 injections. Filter cost: 2 PLN. Column cost: 1800 PLN.

Complete Method PDF

Full protocol with all parameters

SOP Template

GMP-compliant SOP template

Validation Protocol

ICH Q2(R1) validation template

Bibliography (.bib)

All references in BibTeX format

Forensic Fix — real failure stories Lessons learned

Real chemists' mishaps — what happened, what helped, what to avoid.

Incorrect integration — publication rejected

Kasia M., PhD Analytical Chemistry, UJ 2025-06-03 Poziom 4/5
What happened:

Submission to JPBA. Reviewer 2: „Peak at 12.4 min shows manual integration, but baseline slope suggests co-elution". I had to revalidate the whole method. 3 months of delay.

💡 Lekcja:

Manual integration = a red flag for reviewers. Solve CO-ELUTION in methods dev, not in integration. Optimise the gradient instead of force-fitting the peak.

48 godzin stracone na niewidoczne piki

Anna K., studentka 2. rok, PW 2024-11-15 Poziom 2/5
What happened:

Day 1 — I prepared the sample, injected it, baseline flat. Day 2 — I repeated it 6× with different samples. Nothing. Wave check? Professor: "Take a look at the DAD scan". λ_max = 214 nm, and I had 254 nm set.

💡 Lekcja:

ALWAYS run a UV scan of an unknown compound BEFORE the method. 254 nm = aromatics only. 210 nm = universal. Time saved: 2 days of work.

Ask about this method

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🔄 Alternatywne produktyMolGod_ALTPROD_1
⚠️ UWAGA NAUKOWA — Single-CAS Integrity
Listed below are OTHER molecules (structural alternatives / Tanimoto similarity). All physicochemical values (MW, pKa, LD50, GHS, spectra) apply to THESE alternatives, NOT the current molecule (CAS 149-57-5). For data on the current molecule see the "Chemical data", "GHS", "Toxicology" accordions above.
Propylene glycol monomethyl ether acetate (PMA)
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L-Lysine HCl – High
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Ethylene glycol diacetate
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Propyl Acetate
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Ethyl acetate
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📄 Certificates of Analysis (CoA) CAS 149-57-5 none MolGod_COA_2

No certificates for this product in the database.

📚 Scientific references (Chicago Author-Date) — click to expand

Batch management and laboratory certification standards — 13 independent sources (ICH Q1/Q3/Q6/Q7/Q10 + ISO 17025 + WHO TRS + 21 CFR 211 + EMA + USP + Ph.Eur. + PIC/S + IPEC-PQG).

  1. International Council for Harmonisation (ICH). 2000. "Q7 Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients." ICH Expert Working Group. [link ↗] — GMP for APIs — adopted by EMA, FDA, MHLW
  2. International Organization for Standardization. 2017. "ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories." ISO. [link ↗] — Lab accreditation standard underpinning every CoA
  3. World Health Organization. 2010. "WHO Good Manufacturing Practices for Pharmaceutical Products: Main Principles (WHO Technical Report Series No. 957, Annex 3)." WHO Press. [link ↗] — WHO TRS No. 957 — global reference for GMP
  4. International Council for Harmonisation (ICH). 2003. "ICH Q1A(R2): Stability Testing of New Drug Substances and Products." International Council for Harmonisation. [link ↗] — Source for batch shelf-life and retest dating
  5. International Council for Harmonisation (ICH). 2006. "ICH Q3A(R2): Impurities in New Drug Substances." ICH. [link ↗]
  6. International Council for Harmonisation (ICH). 1999. "ICH Q6A: Specifications for New Drug Substances and Products." ICH. [link ↗] — CoA acceptance-criteria specification standard
  7. International Council for Harmonisation (ICH). 2008. "ICH Q10: Pharmaceutical Quality System." ICH. [link ↗]
  8. U.S. Food and Drug Administration. 2024. "21 CFR Part 211: Current Good Manufacturing Practice for Finished Pharmaceuticals." US Code of Federal Regulations. [link ↗] — US legal mandate (Subpart J — Records and Reports)
  9. European Medicines Agency. 2014. "Guideline on Process Validation for Finished Products — Information and Data to Be Provided EMA/CHMP/CVMP/QWP/BWP/70278/2012." European Medicines Agency. [link ↗]
  10. United States Pharmacopeial Convention. 2024. "United States Pharmacopeia and National Formulary, USP 47-NF 42." USP. [link ↗]
  11. European Pharmacopoeia Commission. 2024. "European Pharmacopoeia 11th Edition." Council of Europe — EDQM. [link ↗]
  12. Pharmaceutical Inspection Co-operation Scheme (PIC/S). 2021. "Guide to Good Manufacturing Practice for Medicinal Products PE 009-15." PIC/S Secretariat, Geneva. [link ↗] — Cross-recognized GMP for 54 inspectorates worldwide
  13. International Pharmaceutical Excipients Council (IPEC) and Pharmaceutical Quality Group (PQG). 2017. "Joint IPEC-PQG Good Manufacturing Practices Guide for Pharmaceutical Excipients." IPEC-Americas. [link ↗] — Excipient-grade CoA standard for non-API ingredients
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📜 Patents (public metadata) no data MolGod_PATENT_2

No public patent metadata was found for this substance in Crossref / OpenAlex at this time. Data will be updated automatically after the next cache refresh (24h).

📚 References (Chicago Author-Date) — click to expand
  1. Anonymous. 2017. "Investigation of (2-Ethylhexanoic acid)." Chemical Effects in Biological Systems (CEBS). https://doi.org/10.22427/ntp-data-dtxsid9025293.
  2. Lebel, Hélène. 2016. "2-Ethylhexanoic Acid." Encyclopedia of Reagents for Organic Synthesis: 1-3. https://doi.org/10.1002/047084289x.rn01903.
  3. Kim, Won-Kil, Kim, Jung-Hun, Choi, Jae-Wook. 2015. "Explosion Risk of 2-Ethylhexanoic Acid." Fire Science and Engineering 29 (6): 20-25. https://doi.org/10.7731/kifse.2015.29.6.020.
  4. Obringer C, Lester C, Karb M et al.. (2023). "Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situation.". Regulatory toxicology and pharmacology : RTP. https://doi.org/10.1016/j.yrtph.2022.105315
  5. French KJ, Strickler MD, Rock DA et al.. (2001). "Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.". Biochemistry. https://doi.org/10.1021/bi010063+
  6. Juberg DR, David RM, Katz GV et al.. (1998). "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.". Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. https://doi.org/10.1016/s0278-6915(97)00168-3
  7. Bui LM, Taubeneck MW, Commisso JF et al.. (1998). "Altered zinc metabolism contributes to the developmental toxicity of 2-ethylhexanoic acid, 2-ethylhexanol and valproic acid.". Toxicology. https://doi.org/10.1016/s0300-483x(97)00171-6
  8. Plonait SL, Nau H, Maier RF et al.. (1993). "Exposure of newborn infants to di-(2-ethylhexyl)-phthalate and 2-ethylhexanoic acid following exchange transfusion with polyvinylchloride catheters.". Transfusion. https://doi.org/10.1046/j.1537-2995.1993.33793325058.x
  9. Pennanen S, Manninen A. (1991). "Distribution of 2-ethylhexanoic acid in mice and rats after an intraperitoneal injection.". Pharmacology & toxicology. https://doi.org/10.1111/j.1600-0773.1991.tb01208.x
  10. Ritter EJ, Scott WJ Jr, Randall JL et al.. (1987). "Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.". Teratology. https://doi.org/10.1002/tera.1420350107
  11. World Intellectual Property Organization. 2024. "Patent Cooperation Treaty (PCT)." https://www.wipo.int/pct/.
  12. U.S. Patent and Trademark Office. 2024. "USPTO Patent Public Search." https://ppubs.uspto.gov/.
  13. European Patent Office. 2024. "Espacenet Patent Search." https://worldwide.espacenet.com/.
  14. Newman, David J., and Gordon M. Cragg. 2020. "Natural Products as Sources of New Drugs over the Nearly Four Decades from 01/1981 to 09/2019." Journal of Natural Products 83 (3): 770-803.
  15. Davies, Mark, Michał Nowotka, George Papadatos, et al. 2015. "ChEMBL Web Services: Streamlining Access to Drug Discovery Data and Utilities." Nucleic Acids Research 43 (W1): W612-W620.
  16. Bickerton, G. Richard, Gaia V. Paolini, Jérémy Besnard, Sorel Muresan, and Andrew L. Hopkins. 2012. "Quantifying the Chemical Beauty of Drugs." Nature Chemistry 4 (2): 90-98.
  17. Meanwell, Nicholas A. 2011. "Synopsis of Some Recent Tactical Application of Bioisosteres in Drug Design." Journal of Medicinal Chemistry 54 (8): 2529-2591.
  18. Ertl, Peter, and Ansgar Schuffenhauer. 2009. "Estimation of Synthetic Accessibility Score of Drug-Like Molecules Based on Molecular Complexity and Fragment Contributions." Journal of Cheminformatics 1: 8.
  19. Hopkins, Andrew L., and Colin R. Groom. 2002. "The Druggable Genome." Nature Reviews Drug Discovery 1 (9): 727-730.
  20. Allison, John R., and Mark A. Lemley. 1998. "Empirical Evidence on the Validity of Litigated Patents." AIPLA Quarterly Journal 26 (3): 185-275.
  21. Patani, George A., and Edmond J. LaVoie. 1996. "Bioisosterism: A Rational Approach in Drug Design." Chemical Reviews 96 (8): 3147-3176.
  22. Lerner, Josh. 1994. "The Importance of Patent Scope: An Empirical Analysis." RAND Journal of Economics 25 (2): 319-333.

REST: /wp-json/molgod/v1/patents/149-57-5?status=active&limit=10

Extended Bibliography (3)

  1. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Anonymous. 2017. "Investigation of (2-Ethylhexanoic acid)." Chemical Effects in Biological Systems (CEBS). https://doi.org/10.22427/ntp-data-dtxsid9025293. link [accessed: 2026-09-23] CC0 (metadata)
  2. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Lebel, Hélène. 2016. "2-Ethylhexanoic Acid." Encyclopedia of Reagents for Organic Synthesis: 1-3. https://doi.org/10.1002/047084289x.rn01903. link [accessed: 2026-09-23] CC0 (metadata)
  3. ★★☆☆☆ CROSSREF 🔓 OPEN ❓ unverified Kim, Won-Kil, Kim, Jung-Hun, Choi, Jae-Wook. 2015. "Explosion Risk of 2-Ethylhexanoic Acid." Fire Science and Engineering 29 (6): 20-25. https://doi.org/10.7731/kifse.2015.29.6.020. link [accessed: 2026-09-23] CC0 (metadata)
Data from PubChemSource: PubChem (NIH)
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📚 REFERENCES (Aggregate bibliography, Chicago Author-Date) 120 items

All scientific sources cited in the accordions above for CAS 149-57-5. Format: Chicago Manual of Style 17th ed., Author-Date system.

🗄️ Scientific databases

  1. NIST. n.d. NIST Chemistry WebBook: CAS 149-57-5. Gaithersburg, MD: National Institute of Standards and Technology. https://webbook.nist.gov/cgi/cbook.cgi?ID=149-57-5.
  2. AIST. n.d. Spectral Database for Organic Compounds (SDBS): CAS 149-57-5. Tsukuba, Japan: National Institute of Advanced Industrial Science and Technology. https://sdbs.db.aist.go.jp/.
  3. Linstrom, Peter J., and William G. Mallard, eds. n.d. NIST Chemistry WebBook: NIST Standard Reference Database Number 69. Gaithersburg, MD: National Institute of Standards and Technology. https://doi.org/10.18434/T4D303.
  4. PubChem. n.d. PubChem Compound Summary: CAS 149-57-5. Bethesda, MD: National Center for Biotechnology Information (NCBI), National Library of Medicine. https://pubchem.ncbi.nlm.nih.gov/#query=149-57-5.

📐 Standards / Guidelines

  1. ICH. 2003. "Stability Testing of New Drug Substances and Products: Q1A(R2)." Geneva: International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. https://database.ich.org/sites/default/files/Q1A%28R2%29%20Guideline.pdf.
  2. National Fire Protection Association (NFPA). 2024. "NFPA 30: Flammable and Combustible Liquids Code." NFPA, Quincy, MA. https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=30.
  3. Occupational Safety and Health Administration (OSHA). 2023. "29 CFR 1910.106 — Flammable Liquids." U.S. Department of Labor, Federal Register. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.106.
  4. European Chemicals Agency (ECHA). 2024. "Annex VI to Regulation (EC) No 1272/2008 (CLP) — Harmonised Classification and Labelling." ECHA, Helsinki / Official Journal of the European Union. https://echa.europa.eu/regulations/clp/clp-classification.
  5. European Committee for Standardization (CEN). 2016. "EN 374-1:2016 — Protective gloves against dangerous chemicals and micro-organisms — Part 1: Terminology and performance requirements for chemical risks." CEN, Brussels. https://standards.cencenelec.eu/dyn/www/f?p=205:110:::::FSP_PROJECT,FSP_ORG_ID:38536,6080&cs=1B0DAA8B85DF42E4A2C70E5D71F0BFA32.
  6. European Committee for Standardization (CEN). 2001. "EN 166:2001 — Personal eye-protection — Specifications." CEN, Brussels. https://standards.cencenelec.eu/dyn/www/f?p=CEN:110:0::::FSP_PROJECT:6541&cs=1F1A4E0A78C4DB6A28DBE2E8C29D89DCF.
  7. European Committee for Standardization (CEN). 2009. "EN 14605:2005+A1:2009 — Protective clothing against liquid chemicals — Performance requirements for clothing with liquid-tight (Type 3) or spray-tight (Type 4) connections." CEN, Brussels. https://standards.cencenelec.eu/dyn/www/f?p=CEN:110:0::::FSP_PROJECT:21581&cs=1A04A2D3C7CC58E9E6CB58D55F7EBFB7E.
  8. National Institute for Occupational Safety and Health (NIOSH). 2017. "Recommendations for Chemical Protective Clothing: A Companion to the NIOSH Pocket Guide." U.S. Department of Health & Human Services / CDC. https://www.cdc.gov/niosh/ncpc/default.html.
  9. Occupational Safety and Health Administration (OSHA). 2011. "Personal Protective Equipment — General requirements." U.S. Department of Labor — 29 CFR 1910.132. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.132.

📖 Books

  1. Hansen, Charles M. 2007. Hansen Solubility Parameters: A User's Handbook, 2nd ed.. Boca Raton, FL: CRC Press. https://www.routledge.com/Hansen-Solubility-Parameters-A-Users-Handbook/Hansen/p/book/9780849372483.
  2. Barton, Allan F. M. 1991. CRC Handbook of Solubility Parameters and Other Cohesion Parameters: 2nd ed.. Boca Raton, FL: CRC Press. https://www.routledge.com/CRC-Handbook-of-Solubility-Parameters-and-Other-Cohesion-Parameters/Barton/p/book/9780849301766.
  3. Connors, Kenneth A., Gordon L. Amidon, and Valentino J. Stella. 1986. Chemical Stability of Pharmaceuticals: A Handbook for Pharmacists, 2nd ed.. New York: Wiley. https://doi.org/10.1002/0471734683.
  4. Rumble, John R., ed. 2019. CRC Handbook of Chemistry and Physics: 100th Edition. Boca Raton, FL: CRC Press. https://hbcp.chemnetbase.com/.
  5. Urben, Peter G. 2017. Bretherick's Handbook of Reactive Chemical Hazards, 8th Edition. Academic Press / Elsevier, Oxford. https://www.sciencedirect.com/book/9780081010594.

📄 Scientific articles (peer-reviewed)

  1. Stefanis, Emmanuel, and Costas Panayiotou. 2008. "Prediction of Hansen Solubility Parameters with a New Group-Contribution Method." International Journal of Thermophysics 29: 568-585. https://doi.org/10.1007/s10765-008-0415-z.
  2. Stoll, Vincent S., and John S. Blanchard. 1990. "Buffers: Principles and Practice: In Methods in Enzymology, vol. 182." San Diego: Academic Press. https://doi.org/10.1016/0076-6879(90)82008-P.

🌐 Websites

  1. ECHA. 2023. "Guidance on the Application of the CLP Criteria." European Chemicals Agency. https://echa.europa.eu/guidance-documents/guidance-on-clp.
  2. European Parliament. 2006. "Regulation (EC) No 1907/2006 (REACH)." Official Journal of the European Union L 396: 1–849.
  3. ECHA. 2023. "Candidate List of Substances of Very High Concern for Authorisation." European Chemicals Agency. https://echa.europa.eu/candidate-list-table.
  4. European Parliament. 2008. "Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging of Substances and Mixtures (CLP)." Official Journal of the European Union L 353: 1–1355.
  5. ECHA. 2017. "Guidance on the Compilation of Safety Data Sheets." Version 3.1. European Chemicals Agency. ECHA-17-G-01-EN. https://echa.europa.eu/documents/10162/23047722/sds_en.pdf.
  6. ECHA. 2022. "Restrictions Under REACH — Annex XVII." European Chemicals Agency. https://echa.europa.eu/substances-restricted-under-reach.
  7. United Nations. 2021. Globally Harmonized System of Classification and Labelling of Chemicals (GHS). 9th revised ed. ST/SG/AC.10/30/Rev.9. New York and Geneva: United Nations. https://unece.org/ghs-rev9-2021.
  8. ECHA. 2020. "Understanding REACH." European Chemicals Agency. https://echa.europa.eu/regulations/reach/understanding-reach.
  9. Snyder, Lloyd R., John W. Dolan, and Joseph J. Kirkland. 2010. Introduction to Modern Liquid Chromatography. Wiley.
  10. Schoenmakers, Peter J.. 1986. Optimization of Chromatographic Selectivity: A Guide to Method Development. Elsevier.
  11. Snyder, L. R., and J. W. Dolan. 2007. High-Performance Gradient Elution: The Practical Application of the Linear-Solvent-Strength Model. Wiley.
  12. Nikitas, Pavlos, and Adrian Pappa-Louisi. 2009. "Retention models for isocratic and gradient elution in reversed-phase liquid chromatography." Journal of Chromatography A 1216: 1737-1755. https://doi.org/10.1016/j.chroma.2008.10.005.
  13. Carr, Peter W.. 2009. "The new physical chemistry of HPLC." Journal of Chromatography A 1216: 1764-1772. https://doi.org/10.1016/j.chroma.2008.11.094.
  14. Dong, Michael W.. 2019. HPLC and UHPLC for Practicing Scientists. Wiley. https://doi.org/10.1002/9781119313793.
  15. Wu, Naijun, and Anton M. Clausen. 2007. "Fundamental and practical aspects of ultrahigh pressure liquid chromatography for fast separations." Journal of Separation Science 30: 1167-1182. https://doi.org/10.1002/jssc.200700026.
  16. Stoll, Dwight R., and Peter W. Carr. 2017. "Two-Dimensional Liquid Chromatography: A State of the Art Tutorial." Analytical Chemistry 89: 519-531. https://doi.org/10.1021/acs.analchem.6b03506.
  17. Dolan, John W.. 2013. "When to Modify Method Conditions." LCGC North America 31: 192-199. https://www.chromatographyonline.com/view/when-modify-method-conditions.
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