Decision letter for "Establishment of rapid, sensitive, and quantitative LC‐ESI‐MS/MS method coupled with liquid‐liquid extraction for measurement of urinary bisphenol A, 4‐ t ‐octylphenol, and 4‐nonylphenol"

Rationale Bisphenol A (BPA), 4-t-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) are ubiquitous manufactured chemicals classified as endocrine disruptors. Now these substances are prevalent and found in a wide range of biological and environmental matrices globally. Acting as xenoestrogens, their target is to bind estrogen receptors and compete against natural hormones. Thus, there is an increasing concern on their negative health consequences.Methods A rapid, sensitive, and robust method was established, validated, and used for the trace analysis of BPA, 4-t-OP, and 4-NP in human urine using liquid chromatography-electrospray ionization-tandem mass spectrometry.Results The linear ranges for BPA, 4-t-OP, and 4-NP were 5.0-500 ng/mL. The correlation coefficient was higher than 0.996. The limit of detection and limit of quantitation for the compounds were 0.001, 0.007, and 0.005 ng/mL and 0.005, 0.023, and 0.180 ng/mL, respectively. The recoveries were as follows: 99.539%-108.557%, 97.780%-110.768%, and 99.694%-106.908% for BPA, 4-NP, and 4-t-OP respectively, with relative standard deviation The established method was also applied effectively for the determination of BPA, 4-t-OP, and 4-NP levels in 15 human urine samples. This method was specifically developed for easy and precise analysis of BPA, 4-t-OP, and 4-NP in human urine. The method developed has been shown to be accurate, precise, and sensitive.