Simultaneous determination of multiple phthalate metabolites and bisphenol-A in human urine by liquid chromatography–tandem mass spectrometry

Abstract

Phthalates and bisphenol A are environmental endocrine-disrupting chemicals used widely in common consumer products. There is increasing concern about human exposure to phthalates and bisphenol A due to the potential adverse effects related to the anti-androgenic activity of phthalates and estrogenic activity of bisphenol A. In assessing environmental exposure to phthalates and bisphenol A, it is essential to have a validated analytical method that can quantify trace concentrations of phthalate metabolites and bisphenol A in humans. In this study, we developed and validated an accurate, sensitive, and robust LC-MS/MS method to simultaneously quantify 5 phthalate monoester metabolites, including mono-methyl phthalate, mono-ethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, mono-2-ethylhexyl phthalate, and bisphenol A in human urine. In this method, the phthalate metabolites and bisphenol A, along with their isotope labeled internal standards, were extracted from 200 μl of human urine using automated off-line solid phase extraction. The analytes were quantitatively determined using LC-MS/MS operated in negative electrospray ionization multiple reaction-monitoring mode. The limit of quantification was 0.3 ng/ml for mono-methyl phthalate, mono-ethyl phthalate, mono-benzyl phthalate and bisphenol A, and 1 ng/ml for mono-butyl phthalate and mono-2-ethylhexyl phthalate. The precision and accuracy were well within the acceptable 15% range. This validated method has been used successfully in assessing exposure to phthalates and bisphenol A in humans.

Trace determination of bisphenol-A in landfill leachate samples by dispersive liquid- liquid microextraction followed by high performance liquid chromatography

“…The efficiency of the presented DLLME method for BPA was compared with other sample preparation techniques such as molecularly imprinted solid phase extraction [34], solid phase extraction [35], molecularly imprinted solid phase microextraction [36], in-tube solid phase microextraction [37], liquid phase microextraction gas chromatography mass spectrometry [38], hollow fiber assisted liquid-phase microextraction gas chromatography mass spectrometry [39] and solid phase extraction liquid chromatography mass spectrometry [40] from the viewpoint of linearity, LOD, RSD and preconcentration factor which are shown in Table 1. It can be observed that the analytical performance of the present method is comparable with other reported extraction methods except methods coupled with mass detector.…”

Characterization of Urinary Phthalate Metabolites Among Custodians

“…The categories of reported use are consistent with a prior evaluation of exposures among custodians using the interval of more or less than 4 h to describe exposure intensity (Obadia et al, 2009). The four different phthalate monoester metabolites (MEP, MMP, MEHP, and MBzP) were quantified in the urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) according to the analytical and quality control methods previously described (Chen et al, 2012). The limit of quantitation (LOQ) for each phthalate metabolite was: MEP (0.5 ng ml ).…”

Isotope dilution gas chromatography with mass spectrometry for the analysis of 4‐octyl phenol, 4‐nonylphenol, and bisphenol A in vegetable oils

“…Internal standard (IS) of D 16 -BPA was prepared in acetonitrile at a concentration of 1000 mg/L, and then diluted to 2.0 mg/L with acetonitrile as working standard solutions. All stock solutions were stored at 4ЊC in the refrigerator.…”

“…Working standard solutions were prepared by mixing 5, 25, 50, 100, and 250 L of mixed working standard (0.2 mg/L), with 25 L internal standard (D 16 -BPA, 2.0 mg/L). The working standard solutions were dried by N 2 flow at 50ЊC, and then derived and analyzed by GC-MS.…”

“…Leaching from packaging can be an additional source of APs to humans, as demonstrated in milk where APs and phthalates ranged from 0.28 to 85.3 mg/kg [10]. Various sample preparation techniques, such as ultrasonic extraction [11] coupled with gel permeation chromatography [12] or SPE [13][14][15][16] have been frequently used for extraction and purification of APs and BPA. Meanwhile, SPME [17], stir bar sorptive extraction [18], and several liquid-liquid microextraction techniques such as dispersive liquid-liquid microextraction [19], have been employed for the determination of APs or phthalate esters in water or aqueous samples.…”