Development of a Method for the Determination of Total Bisphenol A at Trace Levels in Human Blood and Urine and Elucidation of Factors Influencing Method Accuracy and Sensitivity

Abstract

This publication describes a method for the determination of total bisphenol A (BPA and conjugated BPA) following enzyme hydrolysis and is intended as a companion to our previously developed analytical method for the determination of free BPA (the aglycone) in human blood and urine using high-performance liquid chromatography-tandem mass spectrometry ( 1). That free BPA method provided a means to account for and/or eliminate background contamination and demonstrated accuracy and reproducibility in both matrices fortified with BPA or a surrogate analyte ((13)C BPA) at a low method quantitation limit (MQL) of 0.1-0.2 ng/mL. In contrast to the free BPA method results and based on stringent accuracy, precision and confirmation criteria set for the MQLs of the method developed for total BPA, the MQL achieved in blood was 1.020-2.550 and 0.510-1.020 ng/mL in urine. These data showed higher MQLs than the desired MQLs of 0.5 ng/mL (blood) and 0.2 ng/mL (urine) with increased variability between analyses which demonstrates the importance of generating method validation data with each analysis. In contrast, the MQL achieved for (13)C BPA-G (monoglucuronide as a surrogate analyte in blood was 0.2-0.5 and 0.2 ng/mL in urine illustrating that the method is capable of meeting lower MQL requirements if the contribution from exogenous BPA can be well controlled. This method for the determination total BPA in human blood and urine is intended to be used in conjunction with the free BPA method ( 1) to obtain accurate and complete BPA biomonitoring data to support human exposure assessments.

Quantification of steroid hormones in low volume plasma and tissue homogenates of fish using LC-MS/MS

“…Various options in the software were tested for optimal analysis in which selection of appropriate peak smoothing significantly improved detection limit of non-derivatized E2. A weighting factor of 1/x was applied to the data (Markham et al, 2014;Vitku et al, 2015) and the linearity of the standard curves was evaluated using correlation coefficient. Coefficient of variations (CV), defined as the ratio of the standard deviation to the mean and represented as a percentage, was used to express the precision and repeatability of the analyses (Blue et al, 2018;Gaikwad, 2013).…”

Bisphenol A in edible tissues of rams exposed to repeated low-level dietary dose by high-performance liquid chromatography with fluorescence detection

“…The BPA standard for sample fortification of the total BPA analysis was prepared in H 2 O, with an MeCN share of ≤ 0.2% (v/v) in the sample‒buffer solution, aimed to prevent the denaturation of β-glucuronidase as in Markham et al ( 2014 ), who demonstrated that the enzyme viability is affected at the organic solvent level of > 0.5% (v/v), particularly at lower concentrations of the analyte (< 2 ng/mL).…”