• Home
  • Search Results
  • Simple and sensitive GC/MS-method for the quantification of urinary phenol, o- and m-cresol and ethylphenols as biomarkers of exposure to industrial solvents.

Simple and sensitive GC/MS-method for the quantification of urinary phenol, o- and m-cresol and ethylphenols as biomarkers of exposure to industrial solvents.

Journal of chromatography. B, Analytical technologies in the biomedical and life sciences (2015-06-06)
T Schettgen, A Alt, P Dewes, T Kraus
ABSTRACT

We have developed and validated a simple and sensitive method for the determination of urinary phenol as well as the urinary metabolites of toluene and ethylbenzene in one analytical run. After enzymatic hydrolysis for the cleavage of conjugates overnight, the analytes are extracted from the matrix with a liquid-liquid extraction procedure using toluene as solvent under acidic conditions. The analytes are then derivatised to volatile ethers using N,O-bis(trimethylsilyl) trifluoroacetamid (BSTFA) for cresols and ethylphenols as well as N-tert-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA) for the determination of phenol. Separation and detection was carried out using capillary gas chromatography with mass-selective detection (GC-MS). Deuterium-labeled o-cresol served as internal standard for the quantification of all metabolites and guaranteed good accuracy of the results. No matrix effects were observed in the quantification of the analytes. The limit of detection for o- and m-cresol and 2- and 4-ethylphenol was 10 and 20μg/l urine and linearity ranged up to 3 and 12mg/L urine, respectively. The limit of detection for urinary phenol was 0.5mg/L with a linear range up to 200mg/L. The relative standard deviation of the within-series imprecision ranged between 3.0 and 7.2% at two spiked concentrations of 60 and 400μg/l and the relative recovery was between 84 and 104%, depending on the analyte. The method was successfully applied in proficiency testing for urinary o-cresol and phenol. This method was used for the analysis of urine samples of 17 non-smoking and 13 smoking persons from the general population without known exposure to solvents. Smokers showed a significantly higher excretion of o-cresol (median: 23 vs. 33μg/l), m-cresol (median: 43 vs. 129μg/l) as well as 4-ethylphenol (median: 25 vs. 124μg/l). Especially excretion of 4-ethylphenol was significantly correlated to smoking habits. The method seems to be suitable for biological monitoring of low-level solvent exposures and allows determination of background values in the general population.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Toluene, anhydrous, 99.8%
Sigma-Aldrich
Sodium hydroxide solution, BioUltra, for molecular biology, 10 M in H2O
Sigma-Aldrich
Hydrochloric acid solution, 1.0 N, BioReagent, suitable for cell culture
Sigma-Aldrich
Sodium hydroxide solution, 1.0 N, BioReagent, suitable for cell culture
Sigma-Aldrich
Hydrochloric acid, 36.5-38.0%, BioReagent, for molecular biology
Sigma-Aldrich
Phenol solution, BioReagent, Equilibrated with 10 mM Tris HCl, pH 8.0, 1 mM EDTA, for molecular biology
Sigma-Aldrich
Phenol, puriss. p.a., ACS reagent, reag. Ph. Eur., 99.0-100.5%
Supelco
Hydrochloric acid solution, volumetric, 0.1 M HCl (0.1N), endotoxin free
Sigma-Aldrich
Phenol, for molecular biology
Supelco
N,O-Bis(trimethylsilyl)trifluoroacetamide with trimethylchlorosilane, with 1% trimethylchlorosilane, for GC derivatization, LiChropur
Sigma-Aldrich
Liquified Phenol, ≥89.0%
Sigma-Aldrich
Acetic acid, natural, ≥99.5%, FG
Sigma-Aldrich
Phenol, BioXtra, ≥99.5% (GC)
Sigma-Aldrich
Phenol solution, Saturated with 0.1 M citrate buffer, pH 4.3 ± 0.2, BioReagent, for molecular biology
Sigma-Aldrich
Phenol, ≥99%
Sigma-Aldrich
N,O-Bis(trimethylsilyl)trifluoroacetamide, ≥99%
Sigma-Aldrich
Hydrogen chloride, ReagentPlus®, ≥99%
Sigma-Aldrich
Phenol, contains hypophosphorous as stabilizer, loose crystals, ACS reagent, ≥99.0%
Sigma-Aldrich
N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tert-Butyldimethylchlorosilane, ≥95%
Sigma-Aldrich
Hydrogen chloride solution, 3 M in cyclopentyl methyl ether (CPME)
Sigma-Aldrich
N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide, >97%
Sigma-Aldrich
Hydrochloric acid solution, ~6 M in H2O, for amino acid analysis
Sigma-Aldrich
Hydrochloric acid solution, 32 wt. % in H2O, FCC
Sigma-Aldrich
Acetic acid, ≥99.5%, FCC, FG
Sigma-Aldrich
4-Ethylphenol, 99%
Sigma-Aldrich
Phenol, puriss., meets analytical specification of Ph. Eur., BP, USP, 99.5-100.5% (GC)
Sigma-Aldrich
Phenol, unstabilized, ReagentPlus®, ≥99%
Sigma-Aldrich
Phenol, BioUltra, for molecular biology, TE-saturated, ~73% (T)
Sigma-Aldrich
m-Cresol, ≥98%, FG
Sigma-Aldrich
Phenol, puriss., ≥99.5% (GC), meets analytical specification of Ph. Eur., BP, USP, crystalline (detached)