A new LC/MS method for specific determination of human systemic exposure to bisphenol A, F and S through their metabolites: Application to cord blood samples

Online Charge-Generation Derivatization by Electrochemical Radical Cations of Thianthrene: Mass Spectrometry Imaging of Estrogens in Biological Tissues

Estrogens play a significant role in endocrinology and oncology. Although separation methods coupled with mass spectrometry (MS) have emerged as a powerful tool for studying estrogens, imaging the spatial distributions of estrogens is crucial but remains challenging due to its low endogenous concentration and poor ionization efficiency. Charge-generation derivatization, such as N-alkylpyridinium quaternization and S-methyl thioetherification, represents a method wherein neutral molecules involving analytes and derivatization reagents undergo chemical reactions to establish permanent charges directly onto the analytes to improve detection sensitivity. Here, we developed a novel derivatization reagent, thianthrene (TT), which enabled oxidization to radical cations ([TT]•+) using an electrochemical method and completed the online charge-generation derivatization of estrogens on a mass spectrometry imaging platform. In this strategy, [TT]•+ can efficiently and selectively derivatize estrogens via an electrophilic aromatic substitution reaction. Results indicated that derivatization with [TT]•+ can significantly enhance imaging sensitivity (3 orders of magnitude), enabling the visualization of estrogen and its metabolites in ovarian and breast tissues. Furthermore, a higher mass intensity of these estrogens was captured in breast para-cancerous tissues than in cancerous tissues, which might provide estrogens spatial dimension information for further research on the initiation and progression of breast cancer.

Conjugated bisphenol S metabolites in human serum and whole blood

Studies have shown that bisphenol S (BPS) is mainly present as its conjugated metabolites in human blood. However, the distribution of conjugated BPS metabolites in different human blood matrices has not been characterized. In this study, paired human serum and whole blood samples (n = 79) were collected from Chinese participants, and were measured for the occurrence of BPS and 4 BPS metabolites. BPS was detectable in 49% of human serum ( Collapse

Key Words

• BPS-G
• BPS-S
• Distribution
• Serum
• Whole blood

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MESH Headings

• Humans
• Phenols/blood
• Phenols/metabolism
• Sulfones/blood
• Sulfones/metabolism
• Male
• Female
• Environmental Pollutants/blood
• Environmental Pollutants/metabolism
• Adult
• Glucuronides/blood
• Glucuronides/metabolism
• Sulfuric Acid Esters/blood
• Middle Aged

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Affiliation(s)

Zhenling Fu Department of Pharmacy, Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, Zhejiang, 324000, PR China
Hangbiao Jin Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, PR China
Weili Mao Department of Pharmacy, Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, Zhejiang, 324000, PR China
Zefu Hu Department of Pharmacy, Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, Zhejiang, 324000, PR China.

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Comprehensive analysis of bisphenol analogues in complex water using a group-targeting aptamer engineered by base mutation

Bisphenol analogues (BPs) are typical environmental hormones with endocrine-disrupting effects and reproductive toxicity requiring analysis and monitoring in complex aquatic environments. However, the presence of various co-existing contaminants makes the accurate determination of total BPs difficult. To address this challenge, there is a strong need to obtain a group-targeting binder to specifically detect a class of BPs. In this work, for the first time we have identified the group-targeting BPs-aptamer with similar affinities for multiple structurally and qualitatively similar BPs. Base mutations were introduced into an aptamer specific to bisphenol A (BPA) and utilized molecular docking calculations to identify a group-targeting aptamer capable of binding BPs, including BPA, bisphenol B (BPB), bisphenol E (BPE) and bisphenol F (BPF) with binding constants in the range of 2.0 × 106 ∼ 2.7 × 106 / M. In addition, an electrochemical aptamer-based sensor (aptasensor) was constructed for highly sensitive and comprehensive analysis of a class of BPs. This aptasensor demonstrated remarkable anti-interference performance against co-existing contaminants at concentrations up to 100-fold and achieved an impressive detection limit of 6.7 pM. This innovative approach of engineering a group-targeting BPs-aptamer is important for the comprehensive analysis of BPs, providing insights into identification and monitoring a class of pollutants.

Cumulative and potential synergistic effects of seven different bisphenols on human granulosa cells in vitro?

Bisphenol (BP) structural analogues of BPA are widely used. Previous studies showed similar effects of BPA and BPS on reproduction in several species including human. We hypothesised that the similar effects of several bisphenols (BPs) could accumulate in granulosa cells (GCs) and affects steroidogenesis. This study investigated the effects of seven BP analogues and their equimolar cocktail on human granulosa cells (hGC) and assessed BPA, BPS, BPF and BPAF level exposures in the follicular fluid of 277 women undergoing Assisted Reproductive Technology. The hGCs were recovered after women oocyte punctures and treated with the seven BP analogues (BPS, BPA, BPAF, BPF, BPAP, BPE and BPB) or their equimolar cocktail of 7 × 1.43 or 7 × 7.14 μM for each of the seven BPs, the sum of BPs reaching 10 ("∑BPs 10 μM"), or 50 μM ("∑BPs 50 μM"), respectively. Oestradiol and progesterone secretion, cell proliferation, viability and expression of steroidogenic enzymes were investigated. Progesterone secretion was decreased by 6 BPs 10 μM and the cocktail "∑BPs 10 μM", (-17.8 to -41.3%) and by all seven BPs 50 μM and "∑BPs 50 μM" (-21.8 to -84.2%). Oestradiol secretion was decreased only by 50 μM BPAF and BPAP (-37.8% and -44%, respectively), with corresponding decreases in CYP17A1 and CYP19A1 gene expression. Cellular proliferation was decreased after treatment with 50 μM BPAF (-32.2%), BPAP (-29%), BPB (-24%) and the equimolar cocktail "∑BPs 50 μM" (-33.1%). BPB (50 μM) and the cocktail "∑BPs 50 μM" increased HSD3B2 mRNA expression. At least one BP was detected in 64 of 277 (23.1%) women follicular fluids. Similar effects of the seven BPs or their cocktail were observed on progesterone secretion and/or on cell proliferation, suggesting cumulative effects of BPs. Our results highlight the urge to consider all BPs simultaneously and to further investigate the potential additive or synergistic effects of several BPs.

Challenges in the Analytical Preparation of a Biological Matrix in Analyses of Endocrine-Disrupting Bisphenols

Endocrine-disrupting chemicals (EDCs) are xenobiotics presented in a variety of everyday products that may disrupt the normal activity of hormones. Exposure to bisphenol A as EDC at trace and ultra-trace levels is associated with adverse health effects, and children are recognized as the most vulnerable group to EDCs exposure. In this review, a summary is presented of up-to-date sample preparation methods and instrumental techniques applied for the detection and quantification of bisphenol A and its structural analogues in various biological matrices. Biological matrices such as blood, cell-free blood products, urine, saliva, breast milk, cordial blood, amniotic and semen fluids, as well as sweat and hair, are very complex; therefore, the detection and later quantification of bisphenols at low levels present a real analytical challenge. The most popular analytical approaches include gas and liquid chromatography coupled with mass spectrometry, and their enhanced reliability and sensitivity finally allow the separation and detection of bisphenols in biological samples, even as ultra-traces. Liquid/liquid extraction (LLE) and solid-phase extraction (SPE) are still the most common methods for their extraction from biological matrices. However, many modern and environmentally safe microextraction techniques are currently under development. The complexity of biological matrices and low concentrations of analytes are the main issues for the limited identification, as well as understanding the adverse health effects caused by chronical and ubiquitous exposure to bisphenols and its analogues.

Influence of mobile phase composition on the analytical sensitivity of LC-ESI-MS/MS for the concurrent analysis of bisphenols, parabens, chlorophenols, benzophenones, and alkylphenols

Phenols are significant environmental endocrine disruptors that can have adverse health effects on exposed individuals. Correlating phenol exposure to potential health implications requires the development of a comprehensive and sensitive analytical method capable of analyzing multiple phenols in a single sample preparation and analytical run. Currently, no such method is available for multiple classes of phenols due to electrospray ionization (ESI) limitations in concurrent ionization and lack of sensitivity to certain phenols, particularly alkylphenols. In this study, we investigated the influence of mobile phase compositions in ESI on concurrent ionization and analytical sensitivity of liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) during the analysis of multiple classes of phenols, and we propose a comprehensive and sensitive analytical method for various classes of phenols (i.e., bisphenols, parabens, benzophenones, chlorophenols, and alkylphenols). The proposed method was affected by 0.5 mM ammonium fluoride under methanol conditions. It enabled the concurrent ionization of all the phenols and significantly improved the analytical sensitivity for bisphenols and alkylphenols, which typically have poor ionization efficiency. This method, combined with a "dilute and shoot" approach, allowed us to simultaneously quantify 38 phenols with good chromatographic behavior and sensitivity. Furthermore, the method was successfully applied to the analysis of 61 urine samples collected from aquatic (swimming) and land (indoor volleyball and outdoor football) athletes.

Comparison of toxicokinetic properties of eleven analogues of Bisphenol A in pig after intravenous and oral administrations

Due to the restrictions of its use, Bisphenol A (BPA) has been replaced by many structurally related bisphenols (BPs) in consumer products. The endocrine disrupting potential similar to that of BPA has been described for several bisphenols, there is therefore an urgent need of toxicokinetic (TK) data for these emerging BPs in order to evaluate if their internal exposure could increase the risk of endocrine disruption. We investigated TK behaviors of eleven BPA substitutes (BPS, BPAF, BPB, BPF, BPM, BPZ, 3-3BPA, BP4-4, BPAP, BPP, and BPFL) by intravenous and oral administrations of mixtures of them to piglets and serial collection of blood over 72 h and urine over 24 h, to evaluate their disposition. Data were analyzed using nonlinear mixed-effects modeling and a comparison was made with TK predicted by the generic model HTTK package. The low urinary excretion of some BPs, in particular BPM, BPP and BPFL, is an important aspect to consider in predicting human exposure based on urine biomonitoring. Despite their structural similarities, for the same oral dose, all BPA analogues investigated showed a higher systemic exposure (area under the plasma concentration-time curve (AUC) of the unconjugated Bisphenol) than BPA (2 to 4 fold for 3-3BPA, BPAF, BPB and BPZ, 7-20 fold for BP4-4, BPAP, BPP, BPFL, BPF and BPM and 150 fold for BPS) due mainly to a considerable variation of oral bioavailability (proportion of BP administered by oral route that attains the systemic circulation unchanged). Given similarities in the digestive tract between pigs and humans, our TK data suggest that replacing BPA with some of its alternatives, particularly BPS, will likely lead to higher internal exposure to potential endocrine disruptive compounds. These findings are crucial for evaluating the risk of human exposure to these emerging BPs.

Determination of multiple bisphenol analogues and their metabolites in human serum by liquid chromatography tandem mass spectrometry

To date, knowledge of internal human exposure to BPA and its analogues (particularly bisphenol S and bisphenol F, etc.) remains limited. In the present study, a method involving dispersive solid-phase extraction and LC/MS was proposed to investigate the contamination levels of 28 precursor bisphenols and 9 major metabolites in serum. The critical variables of preparation method were screened out by Plackett-Burman design and further optimized by central composite design. Left in optimal conditions, a total of 286 samples consisting of 153 males and 133 females were analyzed. The results showed that BPA dominated over all the cases with the highest positive rate (82.2% of all the surveyed people), and totally four metabolites (BPA β-D-glucuronide, BPA monosulfate, BPA bis-(β-D-glucuronide) and BPS monosulfate) were detectable. The occurrence of BPA bis-(β-D-glucuronide) in serum is reported for the first time and its higher positive rate and contamination concentrations suggested that it may be a more important metabolite of BPA than others. Negligible potential risk of health effects to blood donors was observed, since the estimated exposure levels (mean 32.1 ng/kg bw/day, 95th 123.2 ng/kg bw/day) were well below far less than the temporary tolerable reference dose of BPA that recommended by the European Food Safety Authority (4 μg/kg bw/day by). The reference level of BPA for healthy population was determined to be 4.09 μg/L via the percentile method.

Multi-residue determination of bisphenol analogues in organism tissues by ultra-high performance liquid chromatography-tandem mass spectrometry

A reliable and sensitive analyzing method was developed and validated for determination of 13 novel bisphenol analogues (BPs) along with bisphenol A (BPA) in organism tissues. The complex organism tissues were treated by ultrasonic-assisted extraction using acetonitrile/formic acid (99:1, v/v), followed by successive purification using enhanced matrix removal-lipid sorbents and primary secondary amine sorbents. The BPs were finally determined by ultra-high performance liquid chromatography-tandem mass spectrometry after derivatization using pyridine-3-sulfonyl chloride. Satisfactory recoveries of 75 - 118% were obtained for the BPs, with good repeatability (RSD < 20%). Matrix interferences were efficiently diminished. The method quantification limits (MQLs) reached 0.003 - 0.1 ng g^-1 dry weight (dw). The validated method was successfully applied to a preliminary investigation of the BPs in wild marine organisms collected from the nearshore waters along the coast of Guangdong, China. Besides BPA, novel BPs such as bisphenol F, bisphenol AF, and tetrabromobisphenol A were also detected at < MDL - 15.5 ng g^-1 dw. This work laid a strong basis for further in-depth research on bioaccumulation of the novel BPs in the environment.

Simple preparation of surface molecularly imprinted polymer based on silica particles for trace level assay of bisphenol F

A new electrochemical sensor based on molecularly imprinted tetraethyl orthosilicate (TEOS)-based porous interface was developed for selective recognition of bisphenol F (BPF) in this study. The sensor was prepared by depositing the solution containing TEOS and L-tryptophan (L-Trp) in the presence of cetyltrimethylammonium bromide (CTAB) as a pore-maker via hydrolysis/condensation reaction on the glassy carbon electrode (GCE). While the surface morphology and structure characterization were carried out using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), electrochemical characterization was performed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The resulted MIP(TEOS:L-Trp)@GCE achieved a wide linear range of 1 × 10^-15-1 × 10^-14 M for BPF detection with an excellent detection limit of 0.291 fM. Furthermore, the recovery of BPF from spiked bottled water and serum samples varied between 98.83 and 101.03%. These results demonstrate that MIP(TEOS:L-Trp)@GCE was found to be a simple, sensitive, and selective smart interface to detect trace pollution even from complicated samples.

Disposition of Bisphenol S metabolites in Sprague-Dawley rats

Bisphenol S (BPS), a primary bisphenol A (BPA) substitute, has shown a comparable estrogenic activity to BPA. To comprehensively evaluate the toxic effect of human BPS exposure, it is necessary to understand the occurrence of free BPS and its conjugated metabolites in human internal tissues, but which remains unclear. In this study, Sprague-Dawley rats were orally and continuously dosed at 500 μg/kg/day to mimic the actual human BPS exposure scenario, and then free BPS and its conjugated metabolites were analyzed in rat internal tissues, blood, and excreta. Results showed that concentrations of free BPS and its metabolites in most rat tissues, excreta, and blood reached the steady state after 9 days of continuous BPS dosage. In rat urine, 81-84% of BPS was present in the conjugated form, with BPS glucuronide (BPS-G) and BPS sulfate (BPS-S) accounting for mean 83% and 16% of total conjugated BPS, respectively. In rat blood, mean 55% of total BPS was present in the conjugated form, with BPS-G (2.4-2.8 ng/mL) being more abundant than BPS-S (0.19-0.25 ng/mL). Among rat tissues, the mean proportion of free BPS was relatively higher in spleen (76%) and stomach (75%), while lower in intestine (14%) and kidney (36%). BPS-G was more abundant than BPS-S in most rat tissues, such as intestine (mean 93% versus 6.5%) and muscle (78% versus 19%). While, the mean proportion of BPS-S (48%) was higher than BPS-G (33%) in rat liver. These data suggest that analyzing human blood and urine may not accurately reflect the contamination of BPS metabolites in human internal tissues. This study contributes to the better understanding of the metabolic fate of BPS in humans.

A porous molecularly imprinted electrochemical sensor for specific determination of bisphenol S from human serum and bottled water samples in femtomolar level

In this study, a porous molecularly imprinted electrochemical sensor was successfully fabricated for the selective assay of bisphenol S (BPS) by introducing N-methacryloyl-L tyrosine functional monomer. The molecularly imprinted polymer (MIP)-based sensor (MA-Tyr@MIP/GCE) was prepared via photopolymerization on the glassy carbon electrode and subsequently characterized by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The analytical performance of the sensor was evaluated via CV and differential pulse voltammetry (DPV) measurements. Under the optimized conditions, the rebinding experiment demonstrated that the peak current of the porous MIP-based sensor obviously decreased with the increase of BPS concentration in the concentration range of 1-10 fM. Therefore, the detection limit was determined as 0.171 fM. It should be underlined that MA-Tyr@MIP/GCE exhibited high sensitivity and excellent selectivity because MA-TyrMA-Tyr@MIP/GCE sensor has a higher imprinting factor (IF) toward BPS in respect to competitive analogs, i.e., bisphenol A, bisphenol B, and bisphenol F. The practical application of the sensor also showed good reproducibility and stability for the detection of BPS in human serum and water samples. These results showed MA-Tyr@MIP/GCE successfully applied for the selective recognition of BPS in biological and water samples with high sensitivity and excellent selectivity.

Sensitive and direct electrochemical detection of bisphenol S based on 1T&2H-MoS2/CNTs-NH2 nanocomposites

A voltammetric sensor was constructed for ultra-trace BPS detection based on the signal amplification effect of 1T&2H-MoS2 and CNTs-NH2 composites.

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.