Biomonitoring of bisphenol A, 4-nonylphenol, and 4-t-octylphenol in Turkish population: exposure and risk assessment.

Biomonitoring studies are important tools to understand the effects of endocrine-disrupting compounds on human health. Up to now, there have been no biomonitoring and risk assessment studies conducted in Turkish population in which urinary bisphenol A (BPA), 4-nonylphenol (4-NP), and 4-t-octylphenol (4-t-OP) levels were measured simultaneously. The aim of this study is to measure urinary BPA, 4-NP, and 4-t-OP on Turkish population and conduct a risk assessment using urinary levels of chemicals of interest. During the study, liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to measure urinary levels of above-mentioned chemicals, and human biomonitoring was used as a risk assessment tool in 103 volunteers, living in Mersin Region, Turkey. Urinary BPA, 4-NP, and 4-t-OP were founded as 0.0079 µg/g creatinine, 0.0177 µg/g creatinine, and 0.0114 µg/g creatinine, respectively. The obtained estimated daily intakes (EDIs) were calculated as 0.095 µg/kg bw/day, 0.041 µg/kg bw/day, and 0.091 µg/kg bw/day, for BPA, 4-NP, and 4-t-OP, respectively. In conclusion, although no potential health risk due to BPA and 4-NP exposure was observed, there might be health risks associated with 4-t-OP exposure in the Turkish population.

Establishment of rapid, sensitive, and quantitative liquid chromatography-electrospray ionization-tandem mass spectrometry 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 <8.26%. CONCLUSIONS: 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.

A Rapid, Precise, and Sensitive LC-MS/MS Method for the Quantitative Determination of Urinary Dopamine Levels via a Simple Liquid-liquid Extraction Technique.

OBJECTIVES: Dopamine (DA) is a prominent biochemically complex neurotransmitter and immunomodulator. The quantification of DA could contribute to a better understanding of how endocrine system, cardiovascular and renal functions are regulated. The study aims to develop a rapid, precise, and extremely sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for routine clinical quantification of DA in urine. MATERIALS AND METHODS: Urine samples were extracted via one simple and rapid liquid-liquid extraction technique; then analyzed using a sensitive LC-MS/MS method developed by multiple reaction monitoring mode. RESULTS: DA and internal standard (IS) retention durations were found to be 2.28 min and 2.24 min, respectively. The mean extraction recovery of DA and DA-IS in urine was above 95.62%. DA calibration curve in urine was linear (r2≥0.998) ranging from 20 ng/mL to 1000 ng/mL. The maximum intra-day and inter-day precisions were 5.87 and 2.81, respectively and coefficients of variation were 10.55% and 7.57%, respectively. CONCLUSION: A rapid, precise, sensitive and quantitative LC-MS/MS detection of DA without the use of derivatization, evaporation, reconstitution and ion-pairing reagents has been developed with a simple and non-invasive sample technique for clinical laboratory applications, basic neuroscience research and drug development studies.

Determination of urinary levels of Bisphenol A in a Turkish population.

Bisphenol A (BPA) is one of the environmental endocrine disrupting chemicals that is widely used in common consumer products. The aim of this study was to report the total urinary BPA concentrations (free plus conjugated) in 200 urine samples (children: 57; male: 74; female: 69) obtained from residents of a Mediterranean city, Mersin. Analyses were performed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and for assessing environmental exposure to free BPA and its major metabolite bisphenol A glucuronide (BPAG) in human urine were determinated. Our results indicated that the free BPA and BPAG concentrations were in the range of 0.06-0.99 µg/g creatinine and 0.24-615 µg/g creatinine, respectively. No statistically significant difference obtained in BPA concentrations between genders (male and female) or domicile of residence (rural and urban) (p > 0.05). In our study, the mean level of detected free BPA was 0.46 µg/g creatinine in the urban area and 0.37 µg/g creatinine in the rural area. The average amount of BPAG was 60.56 µg/g creatinine in the urban area and 30.28 µg/g creatinine in the rural area. The data demonstrate that determined amount of total BPA in the present study is lower than the results of similar studies conducted in developed countries. There is no data about the levels of BPA in humans and environment in Turkey. Because of this reason, present study is very important since it is the first study in Turkey which determined the concentrations of free BPA and total BPA in human.

Development and validation of an LC-MS/MS method for simultaneous quantitative analysis of free and conjugated bisphenol A in human urine.

Bisphenol A (BPA) is an environmental endocrine-disrupting chemicals that is widely used in common consumer products. There is an increasing concern regarding human exposure to BPA owing to the potential adverse effects associated with its estrogenic activity. For assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and selective analytical method, especially one that can detect low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography-tandem mass spectrometry method for simultaneous quantification of free BPA and BPA ß-d-glucuronide (BPA-gluc) concentrations in human urine with only a single injection. Calibration curves were linear over a concentration range of 1-100 ng/mL for BPA and 10-1000 ng/mL for BPA-gluc. The levels of the analytes were determined quantitatively with HPLC/ESI-MS/MS by using negative electrospray ionization in the select ion monitoring mode and a pentaflouraphenyl propyl column. The validated method was applied to the analysis of spot urine specimens collected from randomly selected healthy human subjects.