Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
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Query Trace: Powell TG [original query] |
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Impact of enzymatic hydrolysis on the quantification of total urinary concentrations of chemical biomarkers
Dwivedi P , Zhou X , Powell TG , Calafat AM , Ye X . Chemosphere 2018 199 256-262 Human exposure to consumer and personal care products chemicals such as phenols, including parabens and other antimicrobial agents, can be assessed through biomonitoring by quantifying urinary concentrations of the parent chemical or its metabolites, often after hydrolysis of phase II conjugates. Developing suitable analytical methods for the concurrent quantification of multiple exposure biomarkers is challenging because optimal conditions for the hydrolysis of such conjugates (e.g., O-glucuronides, N-glucuronides, sulfates) may differ depending on the biomarker. We evaluated the effectiveness of seven commercial hydrolytic enzymes to simultaneously hydrolyze N-glucuronides (using the antibacterial triclocarban as example compound) and other conjugates (using select phenols and parabens as examples) by using on-line solid phase extraction-high performance liquid chromatography-isotope dilution-tandem mass spectrometry. Incubation (30min, 55 degrees C) with a genetically engineered beta-glucuronidase (IMCS, >/=15 units/muL urine) hydrolyzed N-glucuronide triclocarban, but did not fully hydrolyze the conjugates of phenols and parabens. By contrast, incubation (4h, 37 degrees C) with solid beta-glucuronidase (Helix pomatia, Type H-1, >/=30 units/muL urine) or liquid beta-glucuronidase/arylsulfatase (Helix pomatia, 30 units/muL urine [i.e., 30 muL/100muL urine]) in the presence of 100muL methanol for 100muL urine completely hydrolyzed N-glucuronide triclocarban and the conjugates of several phenols and parabens, without cleaving the ester bond of the parabens to form p-hydroxybenzoic acid. These results highlight the relevance of method validation procedures that include optimizing the hydrolysis of phase II urinary conjugates (e.g., enzyme type and amount used, reaction time, temperature) to quantify accurately and concurrently multiple exposure biomarkers for biomonitoring purposes. |
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