A robust and validated method for the determination of 21 urinary metabolites of 15 plasticizers, including phthalates, DEHTP, and DINCH, by online SPE and liquid chromatography-tandem mass spectrometry.

Authors

Rosa Mercadante, Simone Cafagna, Marco Rizzo, Elisa Roggia, Silvia Fustinoni

Published in

Analytical and bioanalytical chemistry. Jul 04, 2026. Epub Jul 04, 2026.

Abstract

Phthalates and their alternative plasticizers terephthalates and hexahydrophthalates are widely used in consumer products, leading to continuous human exposure and potential risk for health. The aim of this study was to develop an analytical assay for the quantification of urinary metabolites of these plasticizers as biomarkers of exposure. Twenty-one urinary metabolites from 15 plasticizers, including 13 phthalates, one terephthalate (di-2-ethylhexyl terephthalate, DEHTP), and one hexahydrophthalate (di-isononyl cyclohexane-1,2-dicarboxylate, DINCH), were deconjugated by enzymatic hydrolysis, separated, and quantified using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) in the presence of 17 isotopically labeled internal standards. A full validation, according to international guidelines, was performed and an external proficiency test was undergone. Forty-six urine samples collected from adults belonging to the Italian general population were assayed to test the method. The analytes, after enzymatic deconjugation, were enriched by online solid phase extraction (SPE); the interferences from contaminants in the mobile phase were delayed with pre-analytical columns and the chromatography was successfully separating all analytes. The assay was precise (% relative standard deviation within 15.6%), accurate (% relative to theoretical value between 96.5 and 108.5%) and sensitive, with lower limits of quantification (LLOQ) in the range 0.10 to 0.78 µg/L. Biases arising from matrix effects and long-term storage had a negligible impact on accuracy, with recoveries remaining within 84-111%. The external proficiency exercise was successful across multiple rounds. In the study sample, the most abundant analytes were monoethyl phthalate (MEP), mono(2-ethyl-5-carboxypentyl) terephthalate (5-cx-MEPTP), monobutyl phthalate (MnBP) and monoisobutyl phthalate (MiBP) (38, 11, 8, and 8 µg/L), metabolites of diethyl phthalate (DEP), DEHTP, di-n-butyl phthalate (DnBP), and di-isobutyl phthalate (DiBP), respectively. The developed method demonstrates good performances, with accurate results and high throughput; it is well-suited for large-scale biomonitoring studies in the general population.

PMID:
42399504
Bibliographic data and abstract were imported from PubMed on 04 Jul 2026.

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