Determination of glyphosate, glufosinate and their major metabolites in urine by the UPLC-MS/MS method applicable to biomonitoring and epidemiological studies.

The preoccupation concerning glyphosate (GLYP) has rapidly grown over recent years, and the availability of genetically modified crops that are resistant to GLYP or glufosinate (GLUF) has increased the use of these herbicides. The debate surrounding the carcinogenicity of GLYP has raised interest and the desire to gain information on the level of exposure of the population. GLYP and aminomethylphosphonic acid (AMPA) are commonly simultaneously analysed. GLUF is sometimes also monitored, but its major metabolite, 3-[hydroxy(methyl)phosphinoyl]propionic acid (3MPPA), is rarely present in the method. Using a pentafluorobenzyl derivative to extract the analytes from human urine, we present a method that contains four important analytes to monitor human exposure to GLYP and GLUF. The use of the flash freeze technique speeds up the extraction process and requires less organic solvent than conventional liquid-liquid extraction. The limits of detection in the low µg/L range enable the use of this method for epidemiological studies. The results obtained for 35 volunteers from the Quebec City area are presented with the results from multiple interlaboratory comparisons (G-EQUAS, HBM4EU and OSEQAS). This methodology is currently being used in the Maternal-Infant Research on Environmental Chemicals (MIREC-ENDO) study and in the Canadian Health Measures Survey (CHMS).

Large Differences in Urinary Benzene Metabolite S-Phenylmercapturic Acid Quantitation: A Comparison of Five LC-MS-MS Methods.

Benzene is a known genotoxic carcinogen linked to many hematological abnormalities. S-phenylmercapturic acid (PHMA, N-acetyl-S-(phenyl)-L-cysteine, CAS# 4775-80-8) is a urinary metabolite of benzene and is used as a biomarker to assess benzene exposure. Pre-S-phenylmercapturic acid (pre-PHMA) is a PHMA precursor that dehydrates to PHMA at acidic pH. Published analytical methods that measure urinary PHMA adjust urine samples to a wide range of pH values using several types of acid, potentially leading to highly variable results depending on the concentration of pre-PHMA in a sample. Information is lacking on the variation in sample preparation among laboratories regularly measuring PHMA and the effect of those differences on PHMA quantitation in human urine samples. To investigate the differences in PHMA quantitation, we conducted an inter-laboratory comparison that included the analysis of 50 anonymous human urine samples (25 self-identified smokers and 25 self-identified non-smokers), quality control samples and commercially available reference samples in five laboratories using different analytical methods. Observed urinary PHMA concentrations were proportionally higher at lower pH, and results for anonymous urine samples varied widely among the methods. The method with the neutral preparation pH yielded results about 60% lower than the method using the most acidic conditions. Samples spiked with PHMA showed little variation, suggesting that the variability in results in human urine samples across methods is driven by the acid-mediated conversion of pre-PHMA to PHMA.

New approach for the determination of ortho-phenylphenol exposure by measurement of sulfate and glucuronide conjugates in urine using liquid chromatography-tandem mass spectrometry.

Ortho-phenylphenol (OPP) has been widely used as a fungicide and preservative. Although low-dose studies have demonstrated its low toxicity in animals and humans, high-dose exposure to this contaminant has toxic effects that range from skin irritation to bladder cancer. Thus far, monitoring of OPP exposure in the general population has been performed by measuring OPP after urine hydrolysis with the ß-glucuronidase/arylsulfatase enzyme and sometimes by the use of a mineral acid. We developed a sensitive, accurate, and robust method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to specifically measure two-phase II OPP metabolites excreted in human urine, OPP sulfate (OPP-S), and OPP glucuronide (OPP-G). Comparative analysis of urine samples from 50 volunteers living in the Quebec City area using a direct method and phosphoric acid hydrolysis method previously developed in our laboratory showed no statistically significant difference (p value for paired t test = 0.701) in OPP concentrations. Moreover, a significant difference showed that underestimation (p value for paired t test = 0.025) occurs when ß-glucuronidase/arylsulfatase enzyme deconjugation is used. The LOD achieved by the direct method permits the detection of OPP-S and OPP-G metabolites in urine at the submicrogram per liter level. Graphical abstract ᅟ.

Determination of bisphenol A, triclosan and their metabolites in human urine using isotope-dilution liquid chromatography-tandem mass spectrometry.

Bisphenol A (BPA) and triclosan (TCS) are ubiquitous environmental phenols exhibiting endocrine disrupting activities that may be involved in various health disorders in humans. There is a need to measure separately free forms and conjugated metabolites because only the former are biologically active. We have developed sensitive methods using isotope-dilution liquid chromatography-tandem mass spectrometry for individual measurements of free BPA and TCS as well as their metabolites, BPA glucuronide (BPAG), BPA monosulfate (BPAS), BPA disulfate (BPADS), TCS glucuronide (TCSG) and TCS sulfate (TCSS) in urine. Comparative analyses of urine samples from 46 volunteers living in the Quebec City area using the new methods and a GC-MS/MS method previously used in our laboratory revealed very strong correlations for total BPA (Spearman's rs=0.862, p<0.0001) and total TCS concentrations (rs=0.942, p<0.0001). Glucuronide metabolites were the most abundant BPA and TCS species in urine samples (>94% of total urinary concentrations). Unconjugated TCS concentrations represented a small proportion of total TCS species (median=1.6%) but its concentration was likely underestimated due to losses by adsorption to the surface of polypropylene tubes used for sample storage. To our knowledge, we are the first to report levels of free, sulfated and glucuronidated TCS levels in human urine.

Urinary and breast milk biomarkers to assess exposure to naphthalene in pregnant women: an investigation of personal and indoor air sources.

BACKGROUND: Naphthalene exposures for most non-occupationally exposed individuals occur primarily indoors at home. Residential indoor sources include pest control products (specifically moth balls), incomplete combustion such as cigarette smoke, woodstoves and cooking, some consumer and building products, and emissions from gasoline sources found in attached garages. The study aim was to assess naphthalene exposure in pregnant women from Canada, using air measurements and biomarkers of exposure. METHODS: Pregnant women residing in Ottawa, Ontario completed personal and indoor air sampling, and questionnaires. During pregnancy, pooled urine voids were collected over two 24-hour periods on a weekday and a weekend day. At 2-3 months post-birth, they provided a spot urine sample and a breast milk sample following the 24-hour air monitoring. Urines were analyzed for 1-naphthol and 2-naphthol and breast milk for naphthalene. Simple linear regression models examined associations between known naphthalene sources, air and biomarker samples. RESULTS: Study recruitment rate was 11.2% resulting in 80 eligible women being included. Weekday and weekend samples were highly correlated for both personal (r = 0.83, p < 0.0001) and indoor air naphthalene (r = 0.91, p < 0.0001). Urine specific gravity (SG)-adjusted 2-naphthol concentrations collected on weekdays and weekends (r = 0.78, p < 0.001), and between pregnancy and postpartum samples (r = 0.54, p < 0.001) were correlated.Indoor and personal air naphthalene concentrations were significantly higher post-birth than during pregnancy (p < 0.0001 for signed rank tests); concurrent urine samples were not significantly different. Naphthalene in breast milk was associated with urinary 1-naphthol: a 10% increase in 1-naphthol was associated with a 1.6% increase in breast milk naphthalene (95% CI: 0.2%-3.1%). No significant associations were observed between naphthalene sources reported in self-administered questionnaires and the air or biomarker concentrations. CONCLUSIONS: Median urinary concentrations of naphthalene metabolites tended to be similar to (1-naphthol) or lower (2-naphthol) than those reported in a Canadian survey of women of reproductive age. Only urinary 1-naphthol and naphthalene in breast milk were associated. Potential reasons for the lack of other associations include a lack of sources, varying biotransformation rates and behavioural differences over time.

Relation between dietary acrylamide exposure and biomarkers of internal dose in Canadian teenagers.

Acrylamide (AA) is a probable human carcinogen found in several foods. Little information is available regarding exposure of adolescents, a subgroup potentially consuming more AA-rich foods. We investigated the relationship between dietary AA intake and levels of biomarkers of exposure (urinary metabolites and hemoglobin adducts) in 195 non-smoking teenagers of Montreal Island aged 10-17 years. Dietary habits and personal characteristics were documented by questionnaire. AA and its metabolites were quantified in 12-h urine collections by LC-MS/MS. Hemoglobin adducts from 165 blood samples were also analyzed by LC-MS/MS. Most prevalent urinary metabolites were NACP and NACP-S, with respective geometric mean concentrations of 31.2 and 14.2 µmol/mol creatinine. Geometric mean concentrations of AAVal and GAVal (hemoglobin adducts of AA and glycidamide (GA) with N-terminal valine residues) were 45.4 and 45.6 pmol/g globin, respectively. AA intake during the 2 days before urine collection was a significant predictor of NACP+NACP-S urinary concentrations (P<0.0001). AA intakes during the month before blood collection (P<0.0001) and passive smoking (P<0.05) were associated with adduct levels. Levels of hemoglobin adducts were above biomonitoring equivalent values corresponding to a 1 × 10(-4) excess cancer risk, which may indicate the need to reduce AA exposure in the population.