Addendum zu: Di(2‐ethylhexyl)phthalat (DEHP)‐Metabolite in Urin, Mono‐n‐butylphthalat (MnBP) und Mono‐iso‐butylphthalat (MiBP) in Urin [Biomonitoring Methods in German Language, 2015]

Abstract

Addendum to: Di(2‐ethylhexyl) phthalate (DEHP) metabolites in urine Mono‐n‐butyl phthalate (MnBP) and monoiso‐butyl phthalate (MiBP) in urine The documentation presents the determination of mono‐n‐butyl phthalate (MnBP) and mono‐iso‐butyl phthalate (MiBP) in urine, which are metabolites of the prominent plasticizers di‐n‐butyl phthalate (DnBP) and diisobutyl phthalate (DiBP). The urine samples are buffered to pH = 6.5 and subjected to enzymatic hydrolysis, together with the deuterium‐labelled internal standard. An arylsulfatase‐free β‐glucuronidase is used for hydrolysis. After separation of possible precipitates by centrifugation, the hydrolysate is injected into the LC–MS/MS system. The analytes are concentrated and higher molecular matrix compounds and more polar substances are separated using a RAM phase column. By employing a backflush, the analytes are rinsed off onto an analytical phenyl‐hexyl column where they are chromatographically separated. Tandem mass spectrometry allows for highly selective detection of the analytes. For calibration, aqueous standard solutions with known concentrations of MnBP and MiBP are used and processed in the same way as the urine samples. For quality control, pooled urines containing high and low native MnBP and MiBP levels were used. The procedure for the determination of DnBP and DiBP metabolites corresponds to the HPLC–MS/MS method for the determination of the main metabolites of Di(2‐ethylhexyl) phthalate (DEHP) in the urine of occupationally or environmentally exposed persons. The present method is therefore an addendum to the procedure for the determination of the DEHP metabolites.