Ultrasound assisted hydrolysis of conjugated parabens in human urine and their determination by UPLC MS/MS and UPLC HRMS
AbstractParabens are preservatives widely used in personal care products, pharmaceutical formulations as well as in food, and they are considered endocrine disruptors. For application in biomonitoring studies we developed a method for the determination of eight parabens from human urine. Sample preparation was enhanced and simplified by the combination of ultrasound assisted enzymatic hydrolysis of conjugates (glucuronide and sulfate) followed by an extraction free cleanup step. Quantification, using deuterated parabens as internal standards, was performed by ultrahigh performance liquid chromatography coupled to either triple quadrupole (UPLC QqQ) or time of flight (UPLC QqTOF) mass spectrometry. Full chromatographic separation of three butyl paraben isomers was achieved. Limits of quantification for both mass analyzers ranged from 0.1 to 0.5 mg/L for methyl, ethyl, n /isopropyl, n /isobutyl, and benzyl paraben in 200 mL of urine sample. The method was tested for applicability and showed high precision (intra and interday 0.9 14.5 as well as high accuracy (relative recovery 95 132 A total of 39 urine samples were analyzed by both mass analyzers. The results agreed well, with a trend to higher deviation at low concentrations (less than 10 mg/L) Methyl, ethyl, and n propyl paraben were detected most frequently (in more than 87 of the samples) with median concentrations ranging from 0.8 to 16.6 mg/L. Female urine showed higher median concentrations for all parabens, which may indicate higher exposure due to lifestyle. This method permits accurate and high throughput analysis of parabens for epidemiological studies. Further, the UPLC QqTOF approach provides additional information on human exposure to other compounds by post acquisition analysis. Graphical abstractAnalytical procedure for paraben analysis from human urine samples including ultrasound enhanced enzymatic digestion of glucuronide and sulfate conjugates, extraction free clean up and quantification by UHPLC MS/MS.
Analytical and Bioanalytical Chemistry