Molecularly imprinted solid-phase extraction for selective extraction of bisphenol analogues in beverages and canned food

Chemical and toxicological characterization of food contact recycled paperboard extracts

Food contact paperboard poses a potential risk of food contamination due to the possible release of chemicals (intentionally added or not), particularly in recycled paperboard. Water extractions were performed, according to wet food procedures, of paperboard samples collected from a manufacturer at the beginning and the end of a recycling production chain. Chemical analysis and hormonal activities in vitro of water extracts were studied. ICP-MS analysis confirmed the presence of 15 trace elements with lower concentrations after the recycling process, with the exception of chlorine. The chromatographic analyses demonstrated that the identified substances in the starting paperboard, before the recycling process, were approximately twice as high as in the end paperboard, after the recycling process. These substances included also natural wood products, chemical additives, and undesirable substances such as phthalates. Two major products (3,5-di-tert-butylphenol and methyl-2-pyrrolidone) were found in the starting and the end paperboard extracts, respectively. Two common substances were identified in both extracts: 2,4-di-tert-buthylphenol and dehydroabietic acid. Evaluation of potential endocrine disruption showed that the starting paperboard extract exhibited oestrogenic and antiandrogenic effects, while these effects nearly disappeared in the end paperboard extract. These results confirmed that the recycling process was effective in removing most of the contaminant substances.

Determination of the occurrence of and exposure to bisphenol A and its analogues in carbonated beverages and canned tuna using liquid chromatography - tandem mass spectrometry

Bisphenol A (BPA), a known endocrine disruptor, is commonly used in food containers and packaging. Recently, alternatives such as bisphenol AF (BPAF), bisphenol B (BPB), and bisphenol E (BPE) have been introduced to replace BPA. However, these substitutes have been reported to exhibit toxicity levels similar to BPA. In this study, we developed and validated a method for the analysis of trace bisphenols (BPA, BPAF, BPB, and BPE) in food using immunoaffinity column (IAC) clean-up. The method demonstrated satisfactory accuracy and precision. We applied this validated method to analyze 56 carbonated beverage samples and 30 canned tuna samples. In the carbonated beverages, average concentrations of BPA and BPAF were 0.4 and 0.2 μg kg-1, respectively. In canned tuna, BPA and BPAF were found at average concentrations of 22.2 and 0.7 μg kg-1, respectively, while BPB and BPE were not detected in any samples. Estimated exposure levels ranged from 0.13 to 0.18 ng kg bw-1 day-1 in the general population and from 205.2 to 232.0 ng kg bw-1 day-1 among consumers. The commercial IAC-based analytical method used in this study can contribute to the safety management of BPA, BPAF, BPB, and BPE.

Assessing dietary bisphenol A exposure among Koreans: comprehensive database construction and analysis using the Korea National Health and Nutrition Examination Survey

Bisphenol A (BPA) exposure primarily occurs through dietary intake. This study aimed to estimate the extent of dietary BPA exposure among Koreans. A thorough literature search was conducted to establish a BPA content database encompassing common foods consumed in Korea, including various food raw materials and processed food products. Dietary exposure levels were estimated by integrating the constructed BPA database with comprehensive nationwide 24 h-dietary recall datasets. The finding revealed that dietary BPA exposure was low for most Koreans, with a mean of 14.5 ng/kg bw/day, but was higher for preschool-age children (over 23 ng). Canned foods accounted for 9-36% of the total dietary exposure of the highest dietary exposure groups; while across all age groups, a considerable amount was derived from canned tuna, contribution of canned fruits and canned coffee (milk-containing) was high for preschool-age children and adults, respectively. Notably, for adults, a substantial proportion also stemmed from beer packaged in cans. While diet contributed over 80% of aggregate exposure for most age groups, preschool-age children experienced 60% exposure through diet due to additional exposure from indoor dust. Even at the high exposure scenario, aggregate BPA exposure levels remained lower than the current tolerable daily intake (TDI) set by the Korean agency (20 μg/kg bw/day). Nevertheless, most Koreans were exposed to BPA levels surpassing the strictest TDI (0.2 ng/kg bw/day) set by the European Food Safety Authority.

Multiple-component covalent organic frameworks for simultaneous extraction and determination of multitarget pollutants in sea foods

Persistent organic pollutants (POPs), such as perfluoroalkyl and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and bisphenols (BPs), have been raising global concerns due to their toxic effects on environment and human health. The monitoring of residues of POPs in seafood is crucial for assessing the accumulation of these contaminants in the study area and mitigating potential risks to human health. However, the diversity and complexity of POPs in seafood present significant challenges for their simultaneous detection. Here, a novel multi-component fluoro-functionalized covalent organic framework (OH-F-COF) was designed as SPE adsorbent for simultaneous extraction POPs. On this basis, the recognition and adsorption mechanisms were investigated by molecular simulation. Due to multiple interactions and large specific surface area, OH-F-COF displayed satisfactory coextraction performance for PFASs, PCBs, and BPs. Under optimized conditions, the OH-F-COF sorbent was employed in a strategy of simultaneous extraction and stepwise elution (SESE), in combination with HPLC-MS/MS and GC-MS method, to effectively determined POPs in seafood collected from coastal areas of China. The method obtained low detection limits for BPs (0.0037 -0.0089 ng/g), PFASs (0.0038 -0.0207 ng/g), and PCBs (0.2308 -0.2499 ng/g), respectively. This approach provided new research ideas for analyzing and controlling multitarget POPs in seafood. ENVIRONMENTAL IMPLICATIONS: Persistent organic pollutants (POPs), such as perfluoroalkyl and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and bisphenols (BPs), have caused serious hazards to human health and ecosystems. Hence, there is a need to develop a quantitative method that can rapidly detect POPs in environmental and food samples. Herein, a novel multi-component fluorine-functionalized covalent organic skeletons (OH-F-COF) were prepared at room temperature, and served as adsorbent for POPs. The SESE-SPE strategy combined with chromatographic techniques was used to achieve a rapid detection of POPs in sea foods from the coastal provinces of China. This method provides a valuable tool for analyzing POPs in environmental and food samples.

Mass Spectrometric Study of the Most Common Potential Migrants Extractible from the Inner Coatings of Metallic Beverage Cans

Population exposure to endocrine disrupting chemical- bisphenols, which are used commonly in food containers and drinking water pipes in Europe, is above acceptable health and safety levels, according to updated research data. In order to evaluate the most abundant potential migrants in canned sweetened beverages marketed in Poland, we performed the HPLC-MS screening test of the migrants present in the can coating material. The analyzed samples represented the three top-ranked companies of the global soft drink market; it is reasonable to assume that the obtained data are of global validity. The tested can coatings and beverages contained bisphenols conjugates such as five butoxyethanol (BuOEtOH) adducts with bisphenol A diglycidyl ether (BADGE), one butoxyethanol adduct with bisphenol A monoglycidyl ether (BAMGE), and cyclo-di-BADGE. The performed HPLC-MS/MS analysis in the MRM mode enabled evaluation of the concentrations of the detected conjugates in canned beverages which were found to be very low, namely at the level of 1 µg/L. On the other hand, the high consumption of canned beverages may yield a risk associated with the presence of these compounds in the diet. The subsequent HPLC-QTOF-MS/MS experiments allowed, for the first time, a detailed determination of the fragmentation pathways of the detected migrants as well as detection of the isomers of the two migrants, namely BADGE + BuOEtOH and BADGE + BuOEtOH + HCl.

Sensory Polymers: Trends, Challenges, and Prospects Ahead

In recent years, sensory polymers have evolved significantly, emerging as versatile and cost-effective materials valued for their flexibility and lightweight nature. These polymers have transformed into sophisticated, active systems capable of precise detection and interaction, driving innovation across various domains, including smart materials, biomedical diagnostics, environmental monitoring, and industrial safety. Their unique responsiveness to specific stimuli has sparked considerable interest and exploration in numerous applications. However, along with these advancements, notable challenges need to be addressed. Issues such as wearable technology integration, biocompatibility, selectivity and sensitivity enhancement, stability and reliability improvement, signal processing optimization, IoT integration, and data analysis pose significant hurdles. When considered collectively, these challenges present formidable barriers to the commercial viability of sensory polymer-based technologies. Addressing these challenges requires a multifaceted approach encompassing technological innovation, regulatory compliance, market analysis, and commercialization strategies. Successfully navigating these complexities is essential for unlocking the full potential of sensory polymers and ensuring their widespread adoption and impact across industries, while also providing guidance to the scientific community to focus their research on the challenges of polymeric sensors and to understand the future prospects where research efforts need to be directed.

Preparation of double-system imprinted polymer-coated multi-walled carbon nanotubes and their application in simultaneous determination of thyroid-disrupting chemicals in dust samples

Dust ingestion is a significant route of human exposure to thyroid-disrupting chemicals (TDCs), and simultaneous determination of multi-contaminants is a great challenge for environmental monitoring. In this study, molecularly imprinted polymer-coated multi-walled carbon nanotubes using thyroxine as the template were synthesized for highly selective TDCs capture. This polymer was prepared by integrating the atom transfer radical polymerization using 2-(3-indol-yl)ethylmethacrylamide as the monomer with the self-polymerization of dopamine. Construction of double-system imprinted cavities could significantly improve their selective recognition performance for TDCs and the coincidence rate reached 88.5 %. The prepared polymers were applied as the solid phase extraction adsorbent to simultaneously determine 7 groups of 35 TDCs. The proposed method showed wide linear range (0.25-1000 ng L-1), low limits of detection (0.02-0.23 ng L-1) and acceptable recoveries (81.8 %-103.5 %). The occurrence and distribution of TDCs were then studied in indoor dust samples (n = 65) collected from four cities in China. We found that tetrabromobisphenol A was the predominant compound and perfluorinated compounds were the most abundant TDCs. In addition, the distribution ratio of TDCs varied between regions. This study provides an efficient technology for direct exposure assessment of multi-contaminants.

Carboxyl functionalized sorbent based solid-phase extraction for sensitive determination of endocrine disrupting chemicals in bottled water, juice and milk

Endocrine disrupting chemicals (EDCs) pose a serious threat to human health even at extremely low concentration. Three carboxyl functionalized porous polymers (PDA-DPBP, PTCDA-DPBP and ODPA-DPBP) were synthesized for the first time and employed as solid-phase extraction sorbent to enrich phenolic EDCs at trace level. Compared with PTCDA-DPBP, ODPA-DPBP and corresponding carboxyl-free counterpart (PC-DPBP), PDA-DPBP delivered superior enrichment efficiency for the phenolic EDCs, which can be ascribed to the strong hydrogen bonding, pore filling, hydrophobic interaction and π-π interaction between PDA-DPBP and phenolic EDCs. Coupled with high performance liquid chromatography, phenolic EDC residues in bottled water, juice and milk samples were enriched and determined. At the optimum conditions, the PDA-DPBP based method provided a good linear response in the range of 0.04-100ng mL-1 for bottled water, 0.07-100ng mL-1 for juice and 0.15-500ng mL-1 for milk samples. The detection limits (S/N=3) were 0.01-0.04, 0.02-0.06 and 0.05-0.10ng mL-1 for bottled water, juice and milk, respectively. The method recoveries were in the range from 81.6% to 116%, with RSDs ≤ 7.7%. This work provides an attractive and reliable alternative method for sensitive determination of phenolic EDCs.

Ten bisphenol analogues in Chinese fresh dairy milk: high contribution ratios of conjugated form, importance of enzyme hydrolysis and risk evaluation

This study investigated concentration levels of ten bisphenols (BPs) in 13 Chinese commercial fresh low temperature dairy milk samples (fresh milk) of main local and national brands with or without enzyme hydrolysis. The results showed that at least two BPs were detected in each fresh milk sample without enzyme hydrolysis and the respective mean concentrations of bisphenol AF (BPAF), bisphenol B (BPB), bisphenol C (BPC), bisphenol F (BPF), bisphenol A (BPA), bisphenol S (BPS), bisphenol AP (BPAP), bisphenol PP (BPP), bisphenol Z (BPZ), and bisphenol E (BPE) were 0.73, 0.61, 1.86, 0.87, 0.42, 0.11, 1.06, 1.42, 1.5, and 0.04 ng/mL, while their respective detection frequencies ranged from 23.1-92.3%. These results indicated the frequent detection of BPs in fresh milk samples. With enzyme hydrolysis, the respective mean concentrations of BPAF, BPA, BPB, BPC, BPF, BPS, and BPAP were increased 7.1-107.1%, indicating the long-ignored importance of enzyme hydrolysis. The respective average estimated daily intakes (EDIs) of BPA by adult and children in China via fresh milk were 32.5 and 37.5 ng/kg bw/d, indicating that BPA in fresh milk was a crucial source to human. Six out of nine other BPs had higher average EDIs than that of BPA, among which the EDI of BPAP was almost three times that of BPA, suggesting the widespread contamination of other BPs in Chinese fresh milk.

Derivatized versus non-derivatized LC-MS/MS techniques for the analysis of estrogens and estrogen-like endocrine disruptors in human plasma

Bisphenols, parabens, alkylphenols and triclosan are anthropogenic substances with a phenolic group that have been introduced to the environment in recent decades. As they possess hormone-like effects, they have been termed endocrine disruptors (EDs), and can interfere with steroid pathways in organisms. To evaluate the potential impact of EDs on steroid biosynthesis and metabolism, sensitive and robust methods enabling the concurrent measurement of EDs and steroids in plasma are needed. Of crucial importance is the analysis of unconjugated EDs, which possess biological activity. The aim of the study was to develop and validate LC-MS/MS methods with and without a derivatization step for the analysis of unconjugated steroids (estrone-E1, estradiol-E2, estriol-E3, aldosterone-ALDO) and different groups of EDs (bisphenols, parabens, nonylphenol-NP and triclosan-TCS), and compare these methods on a set of 24 human plasma samples using Passing-Bablok regression analysis. Both methods were validated according to FDA and EMA guidelines. The method with dansyl chloride derivatization allowed 17 compounds to be measured: estrogens (E1, E2, E3), bisphenols (bisphenol A-BPA, BPS, BPF, BPAF, BPAP, BPZ, BPP), parabens (methylparaben-MP, ethylparaben-EP, propylparaben-PP, butylparaben-BP, benzylparaben-BenzylP), TCS and NP, with lower limits of quantification (LLOQs) between 4 and 125 pg/mL. The method without derivatization enabled 15 compounds to be analyzed: estrogens (E1, E2, E3), ALDO, bisphenols (BPA, BPS, BPF, BPAF, BPAP, BPZ), parabens (MP, EP, PP, BP, BenzylP) with LLOQs between 2 and 63 pg/mL, and NP and BPP in semiquantitative mode. Adding 6 mM ammonium fluoride post column into mobile phases in the method without derivatization achieved similar or even better LLOQs than the method with the derivatization step. The uniqueness of the methods lies in the simultaneous determination of different classes of unconjugated (bioactive) fraction of EDs together with selected steroids (estrogens + ALDO in the method without derivatization), which provides a useful tool for evaluating the relationships between EDs and steroid metabolism.

Recent molecularly imprinted polymers applications in bioanalysis

Molecular imprinted polymers (MIPs) as extraordinary compounds with unique features have presented a wide range of applications and benefits to researchers. In particular when used as a sorbent in sample preparation methods for the analysis of biological samples and complex matrices. Its application in the extraction of medicinal species has attracted much attention and a growing interest. This review focus on articles and research that deals with the application of MIPs in the analysis of components such as biomarkers, drugs, hormones, blockers and inhibitors, especially in biological matrices. The studies based on MIP applications in bioanalysis and the deployment of MIPs in high-throughput settings and optimization of extraction methods are presented. A review of more than 200 articles and research works clearly shows that the superiority of MIP techniques lies in high accuracy, reproducibility, sensitivity, speed and cost effectiveness which make them suitable for clinical usage. Furthermore, this review present MIP-based extraction techniques and MIP-biosensors which are categorized on their classes based on common properties of target components. Extraction methods, studied sample matrices, target analytes, analytical techniques and their results for each study are described. Investigations indicate satisfactory results using MIP-based bioanalysis. According to the increasing number of studies on method development over the last decade, the use of MIPs in bioanalysis is growing and will further expand the scope of MIP applications for less studied samples and analytes.

Temporal trend of bisphenol S occurrence in meat samples from 2008-2020 Canadian total diet study

In our previous study, bisphenol S (BPS) was detected unexpectedly and at high levels in meat samples from 2016 and 2020 Canadian total diet study (TDS). In this study, samples of meat and meat products from 2008-2015 and 2017-2019 TDS were also analysed to investigate the consistency of BPS occurrence in meat and identify possible trends and provide some information on the potential sources for BPS in meat. BPS was detected again with the highest levels observed in samples of fresh pork (105 ng/g) and veal cutlets (140 ng/g) from the 2008 TDS. This indicates that the occurrence of BPS in meat is not a recent phenomenon but rather an existing one since 2008 or even earlier. BPS concentrations in meat samples from the 2008 to 2020 TDS varied significantly, e.g. 1.2-118 ng/g in roast beef, 1.8-140 ng/g in veal cutlets, but no trend was observed. The lack of trend for BPS over the period of 13 years (2008-2020) does not support the speculation that BPS is being used to replace BPA in food packaging, and sources other than food packaging may be possible and should be investigated for BPS.

Free versus droplet-bound aroma compounds in sparkling beverages

The initial experience of a beverage's flavor after opening the bottle is created by a combination of the gas phase and droplet-bound odorants. However, most studies do not consider this combination, and focus on the odor-active components in the liquid or gas phase, separately. To cover this aspect, a filter from pyrolyzed polyacrylonitrile fiber was packed inside thermal desorption unit liner and used for trapping droplet-bound odorants. Additionally, polydimethylsiloxane coated thin-film was applied for extraction of gas-phase aroma. Following trapping/extraction, the devices were desorbed and compounds were separated using GC-MS. The odorants in commercial sparkling beverages were quantified immediately after opening the bottle to mimic real-life conditions of the consumer's experience of the flavor. The reported results provide a more comprehensive understanding of flavor perception in effervescent drinks by considering both gas and droplet phase.

Bisphenol S in individual and composite meat and meat products and implication for its sources

In this study, the occurrence of bisphenol S (BPS) in the meat and meat products from a recent Canadian Total Diet Study (TDS) was investigated in more detail. In addition to their composite samples, the individual raw meat and meat products were also analysed for BPS to investigate the variations of BPS levels and provide some information on the potential sources for BPS in meat. BPS was detected in all the 11 composite samples of different meat and meat products, with the highest level in roast beef (118.23 ng/g) and lowest in cured pork (0.14 ng/g) and cold cuts luncheon meats (0.18 ng/g). BPS was also detected in all the 84 individual raw meat and meat products, with the highest level of 257.61 ng/g in roast beef, followed by 190.41 ng/g in organ meats, 110.15 ng/g in beef steak, 27.91 ng/g in veal cutlets, 17.63 ng/g in wieners & sausages, and 15.27 ng/g in ground beef. However, significant variations of BPS levels were observed in the individual meat and meat product samples under the same category collected from different stores. This may indicate that packaging is unlikely the sources for BPS in meat otherwise BPS levels would have been more or less the same with the same type of packaging (Styrofoam and cling film) regardless where they were collected. Thus, sources other than food packaging, such as the contaminated feed and farming environment (e.g. grass) for animals (e.g. cow), may be possible and should be investigated in future studies.

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review

Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.

Exposure to Triclosan and Bisphenol Analogues B, F, P, S and Z in Repeated Duplicate-Diet Solid Food Samples of Adults

Triclosan (TCS) and bisphenol analogues are used in a variety of consumer goods. Few data exist on the temporal exposures of adults to these phenolic compounds in their everyday diets. The objectives were to determine the levels of TCS and five bisphenol analogues (BPB, BPF, BPP, BPS, and BPZ) in duplicate-diet solid food (DDSF) samples of adults and to estimate maximum dietary exposures and intake doses per phenol. Fifty adults collected 776 DDSF samples over a six-week monitoring period in North Carolina in 2009-2011. The levels of the target phenols were concurrently quantified in the DDSF samples using gas chromatography/mass spectrometry. TCS (59%), BPS (32%), and BPZ (28%) were most often detected in the samples. BPB, BPF, and BPP were all detected in <16% of the samples. In addition, 82% of the total samples contained at least one target phenol. The highest measured concentration of 394 ng/g occurred for TCS in the food samples. The adults' maximum 24-h dietary intake doses per phenol ranged from 17.5 ng/kg/day (BPB) to 1600 ng/kg/day (TCS). An oral reference dose (300,000 ng/kg/day) is currently available for only TCS, and the adult's maximum dietary intake dose was well below a level of concern.

Rapid elimination of trace bisphenol pollutants with porous β-cyclodextrin modified cellulose nanofibrous membrane in water: adsorption behavior and mechanism

A porous β-cyclodextrin modified cellulose nano-fiber membrane (CA-P-CDP) was fabricated and employed to treat the trace bisphenol pollutants (bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF)) in water. The characterization highlighted the porous structure, stable crystal structure, good thermal stability of the obtained CA-P-CDP, as well as abundant functional groups, which could greatly improve the adsorption of bisphenol pollutants and recovery. During the static adsorption process, the adsorbents dosage, temperature and pH showed significant influence on the adsorption performance. At the selected conditions (25 °C, 7.0 of pH and 0.1 g L^-1 of CA-P-CDP dosage), the BPA/BPS/BPF adsorption on CA-P-CDP could rapidly reached the equilibrium in 15 min by following the pseudo-second-order kinetic model, and the maximum adsorption capacities were 50.37, 48.52 and 47.25 mg g^-1, respectively, according to Liu isotherm model. The mechanisms between the bisphenol pollutants and CA-P-CDP mainly involved the synergism of hydrophobic effects, hydrogen-bonding interactions and π-π stacking interactions. Besides, the dynamic adsorption data showed that the volume of treated water for CA-P-CDP (0.58 L) was 14.5 times larger than that of pristine cellulose membrane (0.04 L), revealing satisfactory adsorption performance of trace BPA in water. Furthermore, during the treatment of real water samples (lake water and river water) with trace bisphenol pollutants, the complete removal of the pollutants were evidently observed, which strongly verified the possibility of CA-P-CDP for the practical application.

Application of chromatographic analysis for detecting components from polymeric can coatings and further determination in beverage samples

Major type of internal can coating used for food and beverages is made from epoxy resins, which contain among their components bisphenol A (BPA) or bisphenol A diglycidyl ether (BADGE). These components can be released and contaminate the food or beverage. There is no specific European legislation for coatings, but there is legislation on specific substances setting migration limits. Many investigations have paid attention to BPA due to its classification as endocrine disruptor, however, few studies are available concerning to other bisphenol analogues that have been used in the manufacture of these resins. To evaluate the presence of this family of compounds, ten cans of beverages were taken as study samples. Firstly, the type of coating was verified using an attenuated total reflectance-FTIR spectrometer to check the type of coating presents in most of the samples examined. A screening method was also performed to investigate potential volatiles from polymeric can coatings of beverages using Purge and Trap (P&T) technique coupled to gas chromatography with mass spectrometry detection (GC-MS). Moreover, a selective analytical method based on high performance liquid chromatography with fluorescence detection (HPLC-FLD) for the simultaneous identification and quantification of thirteen compounds including bisphenol analogues (BPA, BPB, BPC, BPE, BPF, BPG) and BADGEs (BADGE, BADGE.H₂O, BADGE.2H₂O, BADGE.HCl, BADGE.2HCl, BADGE.H2O.HCl, cyclo-di-BADGE) in the polymeric can coatings and in the beverage samples was applied. In addition, a liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was optimized for confirmation purposes. The method showed an adequate linearity (R² >0.9994) and low detection levels down to 5 µg/L. Cyclo-di-BADGE was detected in all extracts of polymeric coatings. The concentrations ranged from 0.004 to 0.60 mg/dm². No detectable amounts of bisphenol related compounds were found in any of the beverage samples at levels that may pose a risk to human health, suggesting a low intake of bisphenols from beverages.

A comprehensive review of the neurobehavioral effects of bisphenol S and the mechanisms of action: New insights from in vitro and in vivo models

The normal brain development and function are delicately driven by an ever-changing milieu of steroid hormones arising from fetal, placental, and maternal origins. This reliance on the neuroendocrine system sets the stage for the exquisite sensitivity of the central nervous system to the adverse effects of endocrine-disrupting chemicals (EDCs). Bisphenol A (BPA) is one of the most common EDCs which has been a particular focus of environmental concern for decades due to its widespread nature and formidable threat to human and animal health. The heightened regulatory actions and the scientific and public concern over the adverse health effects of BPA have led to its replacement with a suite of structurally similar but less known alternative chemicals. Bisphenol S (BPS) is the main substitute for BPA that is increasingly being used in a wide array of consumer and industrial products. Although it was considered to be a safe BPA alternative, mounting evidence points to the deleterious effects of BPS on a wide range of neuroendocrine functions in animals. In addition to its reproductive toxicity, recent experimental efforts indicate that BPS has a considerable potential to induce neurotoxicity and behavioral dysfunction. This review analyzes the current state of knowledge regarding the neurobehavioral effects of BPS and discusses its potential mode of actions on several aspects of the neuroendocrine system. We summarize the role of certain hormones and their signaling pathways in the regulation of brain and behavior and discuss how BPS induces neurotoxicity through interactions with these pathways. Finally, we review potential links between BPS exposure and aberrant neurobehavioral functions in animals and identify key knowledge gaps and hypotheses for future research.

In vitro evaluation of the hepatic lipid accumulation of bisphenol analogs: A high-content screening assay

Bisphenol A (BPA) has a variety of adverse effects on human health; therefore, BPA analogs are increasingly used as replacements. Notably, recent studies have revealed that BPA exposure induced hepatic lipid accumulation, but few studies are available regarding the similar effects of other bisphenol analogues (BPs). Thus, in the present study, a high-content screening (HCS) assay was performed to simultaneously evaluate the hepatic lipid accumulation of 13 BPs in vitro. The BPs induced lipid deposition in HepG2 cells ranking as below: 4,4'-thiodiphenol (TDP) < bisphenol S (BPS) < 4,4'-dihydroxybenzophenone (DHBP) < tetrabromobisphenol A (TBBPA) < tetrachlorobisphenol A (TCBPA) < bisphenol E (BPE) < bisphenol F (BPF) < bisphenol B (BPB) < bisphenol AF (BPAF) < bisphenol A (BPA) < bisphenol C (BPC) < tetramethylbisphenol A (TMBPA) < bisphenol AP (BPAP). Meanwhile, Oil Red O staining and triacylglycerol detection further validated the lipid accumulation elicited by the latter 8 BPs, which exhibited the more significant effects on lipid deposition. Mechanistically, significantly increased expressions of genes involved in fatty acid synthesis and nuclear receptors and decreased levels of genes associated with fatty acid β-oxidation were observed under BPs treatment. Therefore, the present work is the first to systematically provide direct evidence for BPs-induced hepatic lipid accumulation in vitro via HCS, which can be helpful for safety assessments of BPs.

Determination of bisphenol A in canned food by microwave assisted extraction, molecularly imprinted polymer-solid phase extraction and liquid chromatography-mass spectrometry

Bisphenol A (BPA), a known potential endocrine disrupting compound (EDC) is expected to be present in low quantities in canned food due to its migration from the inner surface coating of cans made of epoxy resins. A selective and confirmatory analytical method, based on microwave assisted extraction (MAE), molecularly imprinted solid phase extraction (MISPE) using a polymer prepared by a non-covalent molecular imprinting technique and liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI/MS) was developed for the determination of BPA in canned pineapple, tuna and mushrooms. First, the effect of the loading medium of hydro- organic solutions on the binding of BPA and its deuterated analogue on the MISPE sorbent was investigated. Subsequently, the effects of the experimental conditions of the microwave assisted extraction (solvent, sample mass/solvent volume, time and temperature) on the obtained recovery of BPA from canned food were assessed and the parameters were optimized to provide maximum recovery and selectivity. It was demonstrated that the combination of MAE with MISPE permits the use of a selective extraction solvent (methanol/water, 4/6, v/v), simplifying the sample preparation steps and enhancing sample clean-up of complex food matrices. The method was validated in different food matrices, using BPA-d16 as internal standard and quantitative relative recoveries were determined. The precision (RSD %) of the method ranged from 7% to 10% and the limit of detection was at low ng/g level for all food matrices. The determined concentration of BPA in commercial canned samples ranged between 7.3 and 42.3 ng/g.

Bisphenol A Analogues in Food and Their Hormonal and Obesogenic Effects: A Review

Bisphenol A (BPA) is the most well-known compound from the bisphenol family. As BPA has recently come under pressure, it is being replaced by compounds very similar in structure, but data on the occurrence of these BPA analogues in food and human matrices are limited. The main objective of this work was to investigate human exposure to BPA and analogues and the associated health effects. We performed a literature review of the available research made in humans, in in vivo and in vitro tests. The findings support the idea that exposure to BPA analogues may have an impact on human health, especially in terms of obesity and other adverse health effects in children.

The occurrence, potential toxicity, and toxicity mechanism of bisphenol S, a substitute of bisphenol A: A critical review of recent progress

Bisphenol S (BPS) has been introduced into the industry as a safer alternative to bisphenol A (BPA). The distribution of BPS has recently become an important issue worldwide, but investigations on the toxicity and mechanisms of BPS remain limited. A review of the literature reveals that BPS has widespread presence in environmental media, such as indoor dust, surface water, sediments, and sewage sludge. It has been detected in plants, paper products, some food items, and even in the human body. In addition, compared to BPA, BPS has a lower acute toxicity, similar or less endocrine disruption, similar neurotoxicity and immunotoxicity, and lower reproductive and developmental toxicity. The mechanisms underlying BPS toxicity may be related to the chemical properties of BPS in the human body, including interactions with estrogen receptors, and binding to DNA and some proteins, subsequently including exerting oxidative stress. However, further investigation on the potential risks of BPS to humans and its mechanisms of toxicity should be conducted to better understand and control the risks of such novel chemicals.

Dietary intake of 4-nonylphenol and bisphenol A in Taiwanese population: Integrated risk assessment based on probabilistic and sensitive approach

4-Nonylphenol (NP) and bisphenol A (BPA) are high-production and high-volume chemicals used to manufacture various commercial products. They are also ubiquitous contaminants that disrupt endocrine systems in wildlife and humans. We collected, from Taiwan cities with the highest food production, and analyzed, using high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS), 278 food samples for NP and BPA from 11 categories. We found background levels of 100% for NP and 72% for BPA in total samples. High levels of contamination (up to 918 and 49.4 μg/kg) were found in some foods of seafood and animal origin. We used a probabilistic approach to calculate daily dietary dose (Monte Carlo-estimated 95th percentile dietary exposure [MCS 95]) from the Taiwan National Food Consumption database for each sex- and age-specified population. For NP and BPA, the highest average daily dose (ADDs) were in the 4- to 6-year-old group (MCS 95 = 1.57/1.28 and 0.157/0.147 [Male/Female] μg/kg bw/day, respectively), and the lowest ADDs were in the ≥65-year-old group (MCS 95 = 0.674/0.581 and 0.054/0.045 [M/F] μg/kg bw/day, respectively). Based on the European Food Safety Authority (4 μg/kg bw/day for BPA) and Danish Institute of Safety and Toxicology guidelines (5 μg/kg bw/day for NP), the 95th percentile HQ of NP and BPA intake in different sex- and age-specified groups in Taiwan posed no risks through dietary exposure. The intake quantity and concentrations of grains, livestock, and seafood are important variables for the integrated risk of NP and BPA. In conclusion, a combination of multiple and long-term exposure via food consumption should be considered rather than individual endocrine-disrupting chemicals during dietary risk assessment in specific populations. SUMMARY: The 95th percentile HQ of NP and BPA intake in different age and sex groups in Taiwan posed no risks through dietary exposure based on probabilistic and sensitive approach.

A Phenolphthalein-Dummy Template Molecularly Imprinted Polymer for Highly Selective Extraction and Clean-Up of Bisphenol A in Complex Biological, Environmental and Food Samples

A molecularly imprinted polymer (MIP) for highly selective solid-phase extraction (SPE) of bisphenol A (BPA) was prepared using phenolphthalein (PP) as the novel dummy template by bulk polymerization. A particle diameter distribution of 40⁻60 μm, a specific surface area of 359.8 m²·g-1, and a total pore volume of 0.730 cm³·g-1 for the prepared PP-imprinted polymer (PPMIP) were obtained. Good selectivity and specific adsorption capacity for BPA of the prepared PPMIP were also demonstrated by the chromatographic evaluation and sorption experiments. The PPMIP as a SPE sorbent was evaluated for the selective extraction and clean-up of BPA from complex biological, environmental, and food samples. Meanwhile, an accurate and sensitive analytical method based on the PPMIP-SPE purification procedure coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) detection has been successfully developed for the rapid determination of BPA from these samples, with detection limits of 1.3 ng·mL-1 for bovine serum and milk, 2.6 ng·mL-1 for human urine and edible oil, 5.2 ng·mL-1 for soybean sauce, and 1.3 ng·g-1 for sediment. The BPA recoveries at two different spiking levels were in the range of 82.1⁻106.9%, with relative standard deviation (RSD) values below 7.7%.

The in vivo action of chronic bisphenol F showing potential immune disturbance in juvenile common carp (Cyprinus carpio)

Bisphenol F (BPF) has been increasingly introduced into industrial applications as a replacement for bisphenol A (BPA), and has emerged as a ubiquitous environmental contaminant worldwide. Few studies have assessed the in vivo toxicities of BPF, particularly long-term exposure toxicities. In the present study, we examined whether long-term BPF exposure in vivo would evoke oxidative stress in the immune system of juvenile common carp. The results suggested that BPF exposure increased ROS content, oxidative stress indices, complement component 3, and immunoglobulin M contents, as well as the expression of inflammatory cytokine genes. Moreover, higher levels of nf-κb p65 gene expression were correlated with the induced ROS content and NF-κB pathway-associated genes, a strong indication that the mode of action of BPF is related to the NF-κB signaling pathway. We also provide evidence that the effects of BPF are comparable to those of BPA with regards to regulation of the immune response in teleosts, and therefore suggest that such chemical analogs should be thoroughly evaluated for their potential toxicity before they can be considered as "safer" replacements.

Occurrence of bisphenol S in the environment and implications for human exposure: A short review

As a substitute of bisphenol A (BPA), bisphenol S (BPS) has been applied in consumer products present in our daily lives. With a similar chemical structure as BPA, BPS has also been demonstrated as an exogenous endocrine disrupting chemical. Compared with a large number of studies on BPA, investigation on BPS has remained limited. In this study, we reviewed the literature of BPS mainly published during 2010-2017, including its environmental distributions, toxicities, and human exposure. The data demonstrated that BPS is now ubiquitous in the environment and found worldwide, but generally with concentration levels lower than BPA in various environment media, including water, sediment, sludge, indoor dust and air, consumer products, and human urine. However, we found that the concentration levels of BPS in aquatic environments, especially water samples, were almost comparable or equal to that of BPA. Our summary also indicated that process speed of substituting BPA with BPS in consumer products in the U.S. was relatively faster than other countries. In addition, we summarized the toxicities of exposure to BPS both in vivo and in vitro experiments. The current data supports that exposure to BPS may have adverse effects on reproductive systems, endocrine systems, and nervous systems in animals and humans, and may trigger oxidative stress. The occurrence of BPS was frequently reported in human urine, but rarely in other human samples. The current research indicates that food is the dominant source for human exposure to BPS, and the contribution of personal care product usage is low. The occurrence of BPS and their metabolites in the human body and the guidelines for BPS exposure merit further investigation.

Ultrasensitive Detection of Capsaicin in Oil for Fast Identification of Illegal Cooking Oil by SERRS

Discrimination of illegal cooking oil is a conundrum in the fields of analytical chemistry and food safety due to complicated sample systems, lack of common targets, and stringent demand of ultrahigh detection sensitivity for corresponding analytical methods. Capsaicin, one of the exogenous molecules that is subsistent in recycled kitchen waste oils, can be regarded as a target for illegal cooking oil identification. Nowadays, tracing capsaicin in oils is implemented mainly by high-performance liquid chromatography-mass spectrometry, which displays shortcomings in high costs and incapableness for field test. Here, we established a surface-enhanced resonance Raman scattering approach to detect capsaicin and identify illegal cooking oils by means of the molecular derivatization treatment of capsaicin. This method features high detection sensitivity with the detection limit of 1.0 × 10^-8 M, rapid response (<7 min detection duration), and simplicity in sample pretreatment, which is available for fast field test of illegal cooking oils.

Newest applications of molecularly imprinted polymers for extraction of contaminants from environmental and food matrices: A review

This paper presents an overview of the recent applications of molecularly imprinted polymers (MIPs) to sample preparation. The review is thought to cover analytical procedures for extraction of contaminants (mainly illegal/noxious organic compounds) from food and environmental matrices, with a particular focus on the various pre-concentration/cleanup techniques, that is offline and online solid-phase extraction (SPE), dispersive SPE (d-SPE), magnetic SPE (MSPE), solid-phase microextraction (SPME) and stir-bar sorptive extraction (SBSE), applied before instrumental quantification. The selectivity and extraction efficiency of MIP-based sorbent phases are critically discussed, also in relation to the physical-chemical properties resulting from the synthetic procedures. A variety of molecularly imprinted sorbents is presented, including hybrid composites embedding carbon nanomaterials and ionic liquids. The analytical performance of MIP materials in sample preparation is commented as function of the complexity of the matrix, and it is compared to that exhibited by (commercial) aspecific and/or immunosorbent phases.

Chlorination of bisphenol F and the estrogenic and peroxisome proliferator-activated receptor gamma effects of its disinfection byproducts

The reaction kinetics and transformation pathways between bisphenol F (BPF) and sodium hypochlorite were investigated at pH values ranging from 6.5 to 8.5 and with different initial concentration ratios. The reaction rate was pH- and free available chlorine (FAC)-dependent: the reaction rate at pH 8.5 was almost 10 times than that at pH 6.5. A total of 40 compounds were tentatively identified as chloro-substituted BPF and polyphenolic compounds by liquid chromatography quadrupole time-of-flight mass spectrometry operating in electrospray ionization mode (LC-ESI-Q-ToF), and 4 main byproducts were confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR). Toxicity tests indicated that the estrogenic effects of chloro-substituted BPF decrease as the chlorine substitution increase. On the contrary, increasing numbers of chlorines on the phenolic rings of BPF enhanced the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) activity. Tetra-chlorinated BPF had an approximately 6.9-fold higher activity than BPF.

Determination of Bisphenols and Related Compounds in Honey and Their Migration from Selected Food Contact Materials

This study reports the analysis of nine bisphenols (BPA, BPAF, BPAP, BPB, BPC, BPE, BPF, BPS, and BPZ) and related compounds (4-cumylphenol and dihydroxybenzophenone) in honey and food simulant. After sample preconcentration with Oasis HLB cartridges, analytes were silylated and analyzed by GC-MS. The validated methods with LODs in sub ng g^-1 were applied to 36 honey samples from European and non-European countries and food simulant stored in selected corresponding containers. Honey samples contained BPA, BPAF, BPE, BPF, BPS, and BPZ in amounts up to 107, 53.5, 12.8, 31.6, 302, and 28.4 ng g^-1, respectively. Under simulating conditions, BPA and BPAF were detected in food simulant up to 42.2 and 19.8 ng mL^-1, respectively. In certain cases, the detected bisphenols in honey probably derive from a source other than the final packaging.