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

A novel magnetite C18/paracetamol/alginate adsorbent bead for simultaneous extraction of synthetic antioxidants and bisphenol A in water samples

A novel magnetic composite bead was synthesized using carbon 18, paracetamol and alginate (mC18/Pa/Alg). The bead was applied to simultaneously adsorb butylated hydroxytoluene, butylated hydroxyanisole, and bisphenol A from water samples by magnetic solid-phase extraction (MSPE). The adsorbed analytes were determined by gas chromatography-flame ionization detection. The morphology and composition of the bead were examined by field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction analysis, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface analysis. The best condition of MSPE included an adsorbent bead made with 0.8% sodium alginate, a 0.3 g adsorbent dose, a sample solution pH of 7, and a desorption time of 20 min in methanol. The proposed method exhibited linearity at concentrations between 0.015 and 1.00 μg mL-1 of analytes. Limits of detection ranged from 6.86 to 9.66 ng mL-1. Recoveries from 80.3 to 100.1% were achieved with interday and intraday precisions (RSDs) of 0.4-4.3%.

Simultaneous determination of the free and total forms of nonylphenol, nonylphenol monoethoxylate, and nonylphenol diethoxylate in human urine by gas chromatography-mass spectrometry

Nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) are widely used in various daily products and have been cataloged as endocrine-disrupting chemicals. Due to their high lipophilicity and low biodegradability, these compounds remain in the environment and enter the human body through the food chain. Growing concerns regarding the potential negative effects of NP, NP1EO, and NP2EO on human health have raised the need for biomonitoring to investigate human exposure to these compounds. In this study, a simultaneous analysis method using solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS) was established by controlling the background contamination of NP, NP1EO, and NP2EO, which are ubiquitous in laboratory environments. The proposed method showed proper linearity of over 0.999 and a recovery greater than 85.8% for all analytes. Accuracy and precision were verified in ranges of 92.97-116.30% and 0.65-9.29%, respectively. The detection limits for NP, NP1EO, and NP2EO were 0.0363 μg L-1, 0.0401 μg L-1, and 0.0364 μg L-1, respectively, which were suitable for determining the trace analytes in human urine. Therefore, this simple and integrated analytical method was applied to measure the free and total forms of the target analytes in 25 human urine samples collected in Korea. Overall, free NP, NP1EO, and NP2EO were detected with average contents of 3.94 ± 4.14 μg L-1, 4.63 ± 2.62 μg L-1, and 0.293 ± 0.638 μg L-1, respectively, and with total NP, NP1EO, and NP2EO contents of 6.14 ± 8.24 μg L-1, 5.99 ± 2.91 μg L-1, and 0.806 ± 1.10 μg L-1, respectively. These data showed that these compounds are prevalent in human urine, and indicate the need for further studies.

A "dilute-and-shoot" column-switching UHPLC-MS/MS procedure for the rapid determination of branched nonylphenol in human urine: method optimisation and some fundamental aspects of nonylphenol analysis

Technical grade branched nonylphenol (NP) was determined in human urine by online solid phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (SPE-UHPLC-MS/MS). Prior to analysis, urine specimens were simply diluted and enzymatically deconjugated. The run time of the chromatography, including SPE and re-equilibration, was 9 min per injection. The enzymatic cleavage of NP conjugates was optimised with incurred sample material from a human metabolism study: the highest recoveries were obtained with β-glucuronidase from E. coli K 12 in 0.1 M ammonium acetate at pH 6.5, within a minimal hydrolysis time of 30 to 60 min. Using sodium acetate instead of ammonium acetate led to systematically decreased recovery rates. The analytical method was validated regarding its precision (coefficients of variation: 2.9-7.4%), accuracy (relative recovery rates: 93-105%), robustness (relative recovery rates in individual urine matrices: 92-117%), selectivity, and limit of quantification (1.0 μg L^-1). Fundamental aspects in the analysis of technical product mixtures such as NP, comprising various isomers and homologues, were considered. Validation results, an exposure scenario and the application of the procedure to real samples, show that it enables a rugged monitoring of NP exposures above, at, and significantly below health-based guidance values, corresponding to daily NP intakes in the low μg kg^-1 d^-1 range. On the other hand, background levels in non-specifically exposed populations cannot be detected with this method. Hence, while alternative approaches should be pursued for NP analysis at environmental trace level, the speed and simplicity of our method are ideal for high-throughput human biomonitoring in occupational medicine.

Application of High-Performance Liquid Chromatography Combined with Fluorescence Detector and Dispersive Liquid-Liquid Microextraction to Quantification of Selected Bisphenols in Human Amniotic Fluid Samples

Bisphenol A (BPA) is a widely produced chemical worldwide found in numerous everyday products. Its endocrine-disrupting properties and omnipresence have aroused concern and led to several restrictions on its use. These restrictions and growing public awareness about the toxicity of BPA have resulted in market products labeled "BPA-free", with BPAs often being replaced by other bisphenols. This is why constant biomonitoring of bisphenol levels in various body fluids and tissues is essential. In this study, we propose the use of simple, cost-effective high-performance liquid chromatography coupled with the fluorescence detector (HPLC-FLD) method for the determination of simultaneously selected bisphenols in amniotic fluid. For the sample preparation, a fast, simple, and "green" dispersive liquid-liquid microextraction (DLLME) method was used, achieving mean recovery values in the range of 80.9-115.9% with relative standard deviations below 12% for all analytes. Limits of quantification (LOQs) determined in the amniotic fluid matrix ranged from 6.17 to 22.72 ng/mL and were obtained from a calibration curve constructed using least-squares linear regression analysis for all cases. The presented sample preparation procedure can be easily adopted for LC-MS analysis.

An efficient 3D adsorbent foam based on graphene oxide/AgO nanoparticles for rapid vortex-assisted floating solid phase extraction of bisphenol A in canned food products

In this study, a three-dimensional adsorbent was developed based on graphene oxide/AgO nanoparticles over interconnected nickel foam (GO/AgO@Ni foam) for rapid and efficient vortex assisted floating solid phase extraction of bisphenol A in canned food products prior to high performance liquid chromatography with a fluorescence detector. The analytical techniques scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) were used for characterization of the synthetized GO/AgO@Ni foam. The effect of proficiency factors including pH, foam size, vortexing time, salt addition, sample volume, desorption type and volume, and desorption time on the extraction efficiency of bisphenol A were explored through the matrix match method. Under the above experimental conditions, the figures of merit of the method were acquired as LODs (S/N = 3) of 0.18-0.84 μg kg^-1, LOQs of 0.61-2.81 μg kg^-1 (S/N = 10), linear ranges of 0.5-500 μg kg^-1, and enrichment factors of 235.5-244.9. The inter-day precision values (RSD%, n = 7) of 2.5-3.6 and the intra-day precision (%) of (5 days and seven replicates for each day) 2.8-3.8 were achieved for bisphenol A at a concentration of 50 μg kg^-1. The relative recoveries of 94.0% to 99.6% were obtained for the canned food samples.

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.

Recent advances in analysis of bisphenols and their derivatives in biological matrices

Biomonitoring is a very useful tool to evaluate human exposure to endocrine-disrupting compounds (EDCs), like bisphenols (BPs), which are widely used in the manufacture of plastics. The development of reliable analytical methods is key in the field of public health surveillance to obtain biomonitoring data to determine what BPs are reaching people's bodies. This review discusses recent methods for the quantitative measurement of bisphenols and their derivatives in biological samples like urine, blood, breast milk, saliva, and hair, among others. We also discuss the different procedures commonly used for sample treatment, which includes extraction and clean-up, and instrumental techniques currently used to determine these compounds. Sample preparation techniques continue to play an important role in the analysis of complex matrices, for liquid matrices the most commonly employed is solid-phase extraction, although microextraction techniques are gaining importance in this field, and for solid samples ultrasound-assisted extraction. The main instrumental techniques used are liquid and gas chromatography coupled with mass spectrometry. Finally, we present data on the main parameters obtained in the validation of the revised methods. This review focuses on various methods developed and applied for trace analysis of bisphenols, their conjugates, halogenated derivatives, and diglycidyl ethers in biological samples to enable the required selectivity and sensitivity. For this purpose, a review is carried out of the most recent relevant publications from 2016 up to present.