title: Ultrasound-assisted hydrolysis of conjugated parabens in human urine and their determination by UPLC-MS/MS and UPLC-HRMS.
abstract: Parabens 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 μg/L for methyl, ethyl, n-/isopropyl, n-/isobutyl, and benzyl paraben in 200 μL 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 μg/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 μg/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.
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Schlittenbauer
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Seiwert
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany. thorsten.reemtsma@ufz.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods*; D005260:Female; D006801:Humans; D006868:Hydrolysis; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D010226:Parabens / Q000032:analysis* / Q000737:chemistry; D011310:Preservatives, Pharmaceutical / Q000032:analysis; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014465:Ultrasonics; D016482:Urinalysis / Q000379:methods*; D055815:Young Adult
chemical_list: D010226:Parabens; D011310:Preservatives, Pharmaceutical; C057775:benzylparaben; C006068:propylparaben
keywords: Deconjugation; Enzymatic digestion; LC–MS/MS; Suspect screening; Urinary biomarker; p-Hydroxybenzoic acid ester