Determination of bisphenol‐A levels in human amniotic fluid samples by liquid chromatography coupled with mass spectrometry

Abstract

Bisphenol A (BPA) is one of the environmental endocrine-disrupting chemicals used widely in common consumer products. There is an increasing concern about human exposure to BPA, particularly in fetuses, due to the potential adverse effects related to the estrogenic activity of BPA. In assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and specific analytical method, particularly for low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography-mass spectrometry (LC-MS) method for determining BPA concentrations in human amniotic fluid. In this method, BPA and the internal standards 13C12-BPA were extracted from 500 μL of human amniotic fluid using solid phase extraction. Calibration curves were linear over a concentration range of 0.3 to 100 ng/mL for BPA. The analytes were quantitatively determined using LC-MS operated in negative electrospray ionization selected ion monitoring mode. This validated method has been used successfully in clinical sample analysis of BPA in second-trimester amniotic fluid specimens.

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

“…We previously reported [25] a validated off-line SPE/LC-MS method for quantifying BPA levels in human aminiotic fluid. Based on this method, we further optimized the SPE procedures under different pHs of loading sample, wash steps, and elution solvents.…”

“…Similarly, no mobile phase additives, such as formic acid, acetic acid, ammonium acetate or ammonia were added in our previous method [25] because we also found that they can cause severe signal suppression for BPA analysis. However, these methods could not be applied to analyze phthalate metabolites under the same analytical conditions since without organic acid (such as acetic acid) added in the mobile phase, the phthalate monoesters, especially MMP, MEP, MBP and MBzP, wouldn’t bind effectively to the stationary phase of the analytical column and eluted out in 2 mins.…”

“…Acetonitrile was chosen because it had slightly higher resolution and better peak shapes for phthalate monoesters than methanol. Since the instrument used in the current method is more sensitive than the LC-MS system used in our previous method [25], and sample clean up by SPE also effectively reduced the interference from matrix, we were able to achieve a good sensitivity for BPA using mobile phase containing 0.1% acetic acid. The HPLC elution gradients and the flow rate were also optimized.…”

“…However, matrix effects from biological matrices such as urine may impair the accuracy and the precision of the method. During our initial method development based on the previous method [25], we had difficulty in detecting low levels of MMP, MEP, BPA and their ISs using 500-μl sample volume. Increasing the urine volume to 1ml decreased the sensitivity and therefore did not solve this problem.…”

Zebrafish: A Marvel of High-Throughput Biology for 21st Century Toxicology

“…However, all amniotic fluid has its origins in maternal plasma, which transports nutrients, electrolytes and water to the embryo, as well as any toxicants and xenobiotics that may be present in maternal circulation and are able to diffuse across the placenta. Not surprisingly, “waterborne” exposures to environmental factors occur; the presence of xenobiotics (9, 10), industrial pollutants (11, 12), medications (13), chemicals in household items (14, 15) and chemicals derived from lifestyle habits (16),(17) have been isolated from human amniotic fluid, which is swallowed, breathed in and recycled by the developing fetus beginning at about week 10 and continuing throughout gestation (8). Consequently, the absorption routes during embryogenesis in humans are probably similar to those in zebrafish, including dermal, gastrointestinal and respiratory, although this has not been rigorously tested.…”