Free Bisphenol Research Articles

Chromatographic Methods for Determining Free Bisphenol A in Technical and Food Products

Chromatographic Methods for Determining Free Bisphenol A in Technical and Food Products

Method of Gas Chromatography–Mass Spectrometry for the Determination of Free Bisphenol A in Ethanol Extracts

Method of Gas Chromatography–Mass Spectrometry for the Determination of Free Bisphenol A in Ethanol Extracts

Side-chain Poly[2]pseudorotaxanes containing β-cyclodextrin for more sustainable tanning process

Sustainability of leather lies in how the hide, a sustainable, naturally renewable, raw material, is processed. Tanning chemistry has been a limiting factor for leather sustainability. In this study, a host-guest synthesis strategy was selected to modify one of the most widely used tanning polymer, MIDA DD, and obtain a new hybrid tanning system containing β-cyclodextrin, and leather drastically less impactful on the earth and people. Poly[2]pseudorotaxane Side-Chain Complexes (PSCCs) have been obtained by threading β-cyclodextrin units onto the side-chains of the commercial MIDA DD. The formation of PSCCs in aqueous solution was investigated by using 1D NMR, ATR-FTIR and TGA experiments. The ability of PSCCs to stabilize the collagen matrix was tested at laboratory and industrial pilot scale by micro-DSC, ATR-FTIR and solid-state NMR techniques. The physical and mechanical performance of the obtained crust leather was determined by standard tests used in tanning industry. Side-chain poly[2]pseudorotaxanes showed better tanning performances than the fossil-based MIDA DD, the most effective supramolecular tannins being obtained by mixing β-CD and MIDA DD in ratios close to 1/1 (w/w). The new tanning mixtures allow for significantly reducing both the amount of fossil-based MIDA-DD polymer in the current tanning processes (by 45%) and the free bisphenol content in leather crust (by more than 80%) due to the presence of bio-based β-CD in the composition of the new supramolecular tanning agents. The findings disclosed here pave the way for the CDs’ employment in improving the sustainability of tanning processes.

Chromatographic methods for the determination of free bisphenol A in technical and food products

The article provides a brief overview of chromatographic methods for the determination of free bisphenol A in technical and food products. Bisphenol A (BPA) is used as a monomer in the production of some plastics and epoxy resins. Free BPA may be present in quantities exceeding acceptable levels in plastic food containers and in food products packaged in these containers. Maximum permissible concentration (MPC) of BPA in the air of the working area is 5 mg/m3, which in terms of liquid is 5 µg/dm3. Maximum permissible concentration for the content of BPA in water, in water bodies for domestic, drinking and community water use is 0.1 mg/dm3. In European countries for plastics in contact with food, the BPA migration value is 0.6 mg/kg. Despite the relatively low toxicity of BPA, it can accumulate in the human body and cause harmful effects. To determine BPA in plastic, food products, and biological fluids, gas chromatography with preliminary derivatization by silylation or acylation of the analyte is most often used. Gas chromatographic techniques for direct chromatography on heat-resistant columns have also been developed. A fluorometric detector and a mass spectrometric detector are used as detection devices, along with a flame ionization detector. An alternative method for determination of BPA is HPLC with optical and mass spectrometric detection methods. The TLC method was also developed for the determination of BPA. For the preparation of BPA samples, solid-phase extraction (SPE), liquid-liquid extraction (LLE), dispersive liquid-liquid microextraction (DLLME), combined extraction method with acetonitrile separation (QuEChERS) are used.

Gas chromatography-mass spectrometry method for the determination of free bisphenol A in ethanol extracts

Gas chromatography-mass spectrometry method for the determination of free bisphenol A in ethanol extracts

Rapid and simultaneous determination of multiple endocrine-disrupting chemicals and their metabolites in human serum and urine samples

Bisphenols, parabens, and their metabolites are a group of chemical compounds with a wide range of polarities but similar chemical structures, which presents a challenge for the simultaneous determination of these compounds in complex biological samples. In this study, a rapid and sensitive method for simultaneous quantification of free bisphenol A (BPA), conjugated BPA, bisphenols, and parabens analogs was developed using solid-phase extraction (SPE) tandem liquid–liquid extraction (LLE). We compared the effects of different types of SPE cartridges, diluents, and LLE solvents on the analyte recovery. Utilizing the direct and indirect determination methods (enzyme hydrolysis), we confirmed the accuracy of the direct method for measuring BPA glucuronide and BPA disulfate. The method enabled the analysis of 24 endocrine-disrupting chemicals (EDCs) in one injection through UHPLC-MSMS measurements, with satisfactory recovery (mean: 91.8–98.6% for urine, 80.2%–96.8% for serum) and precision (RSD <15%). The LOD and LOQ values were 0.003 and 0.01 ng/mL for serum, and 0.002 and 0.006 ng/mL for urine samples, respectively. For real sample analysis, the median concentration of analytes in serum and urine samples ranged from 0.04 ng/mL (BPS) to 56.4 ng/mL (4-HB) and 0.11 ng/mL (BPA) to 136 ng/mL (4-HB), respectively. This method provides a new strategy to simultaneously identify compounds with a wide range of polarities from complicated biological matrices.

Bisphenol A Exposure On Exclusively Breastfed Infants In Lactating Women: An Observational Cross-Sectional Study

Bisphenol A exposure is crucial for lactating women and exclusively breastfed infants. Bisphenol A transfers directly by breastfeeding and may cause adverse health outcomes. We conduct this study to determine maternal human milk bisphenol A level and exclusively breastfed infants' bisphenol A exposure. We investigated the effect of exposure according to participants' nutritional habits. We enrolled voluntarily, healthy postnatal, exclusively breastfeeding women (n=80) and collected hindmilk samples. Human milk-free bisphenol A concentration was analyzed using a competitive ELISA method. Free (unconjugated) BPA has been detected in human samples indicating that humans are internally exposed to estrogenically active BPA. Participants' demographic properties, nutritional habits were questioned with an elaborated survey face-to-face by the researcher. Human milk median free bisphenol A level is 0.63 µg/L. There was no statistically significant association between maternal body mass index, birth type, parity, infant birth week, infant birth weight, and human milk bisphenol A concentration. Nevertheless, we only found a statistically significant association between human milk bisphenol A level and fast-food, carbonated drinks consumption (p=0.022 and p=0.018, respectively). Exclusively breastfed infants' bisphenol A exposure was 0.0099±0.0079 µg/kg bw/day. There was a negative moderate statistically significant correlation between infant bisphenol A exposure and infant current body weight (r= 0.327, p=0.003). Exclusively breastfed infants bisphenol A exposure was under the tolerable bisphenol A level (4 µg/kg bw/day), and infants' current dietary exposure level was safe.

Determination of Free Bisphenol A in Commercially Packaged Ready-to-Consume Carbonated/Non-Carbonated and Non-Alcoholic Beverages with Immunoaffinity Column Purification and UPLC with Fluorescence Detector, First Action 2019.07.

Bisphenol A (BPA) is a chemical of concern in the food industry. There is a need for a sensitive analytical method for the determination of BPA in beverages. To develop a method for the determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks. Replicates of a carbonated soft drink, orange juice with pulp, and a dairy-based coffee drink at spiking levels ranging from 0 to 32 ng/mL were analyzed. The carbonated soft drink was adjusted to pH 7.4 and diluted with phosphate buffered saline (PBS). The orange juice with pulp and the dairy-based coffee drink were extracted with methanol and sodium chloride, then diluted with PBS. LOD ranged from 0.06 to 0.08 ng/mL and LOQ ranged from 0.10 to 0.14 ng/mL. Recoveries of BPA from all sample types at 1 to 16 ng/mL spiked levels were between 93 and 100%; relative standard deviation (RSDr, %) ranged from 0.71 to 8.38% depending on matrix and spiking levels. The results indicate that the method for determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks is reproducible and meets AOAC Official MethodSM performance criteria. The test portions were filtered and the filtrates applied to an immunoaffinity column (IAC) containing antibodies specific for BPA. After the column was washed with water, BPA was eluted from the IAC with 80% methanol and the eluate was directly injected, or concentrated and injected, into ultra-performance liquid chromatography (UPLC) with fluorescence detector (FLD) for separation, detection, and quantitation.

Determination of free and total bisphenol A in the urine and feces of orally and subcutaneously dosed sheep by high-performance liquid chromatography with fluorescence detection

An analytical procedure has been introduced to enable a study of the excretion of free bisphenol A (BPA), total BPA and its main metabolite bisphenol A glucuronide (BPA–GLUC). In the experiment, in which 100 μg/kg b. w. BPA was administered daily to one Istrian Pramenka sheep for 5 days with consecutive urine and feces samples being taken, BPA and total BPA were determined in samples using high-performance liquid chromatography (HPLC) with fluorescence detection. Because of their good recovery, precision, and sensitivity, the methods have also proved applicable to further ecotoxicological studies of free BPA, BPA–GLUC and total BPA. The results were subsequently compared with reported field studies of BPA in livestock excreta.

Preliminary toxicokinetic study of BPA in lactating dairy sheep after repeated dietary and subcutaneous administration

Dietary intake is the predominant route of human exposure to bisphenol A and one of the important food commodities is milk. The aim of our study was to preliminarily evaluate the bisphenol A exposure and disposition in sheep milk after repeated dietary and subcutaneous administration of a relatively low dose (100 µg/kg of b. w./day) of bisphenol A to a sheep. On the basis of blood plasma sampling, milk sampling and HPLC analysis, we developed the toxicokinetic model. With the toxicokinetic model we showed that most likely only free bisphenol A passes into the mammary gland and is subsequently conjugated there. The percentage of the dose eliminated with milk was less than 0.1%, regardless of the route of bisphenol A administration. It is proven that the bisphenol A is eliminated through the milk of lactating sheep. However, the amounts excreted in the milk that were detected in this study are minimal.

Exposure to bisphenol A and diabetes risk in Mexican women.

Bisphenol A (BPA) is an endocrine-disrupting chemical widely used in the production of polycarbonate plastics and epoxy resins, which has been previously linked to diabetes among non-Hispanic populations. As part of a case control study for breast cancer, only controls with BPA information were included in this report. The final sample size comprises 70 self-reported diabetics and 334 non-diabetics. Urinary free bisphenol A (BPA-F) (μg/L) was determined by solid-phase extraction and HPLC/FLD analysis. Logistic regression models were used to evaluate the association between BPA-F and self-reported diabetes. After adjusting by age, urinary BPA-F (4.06-224.53μg/g creatinine) was associated with diabetes exposure (OR =1.85; 95% CI 1.04, 3.28) compared with women in the reference category (0.67-4.05μg/g creatinine). BPA may be an environmental cofactor of diabetes. More studies are needed to confirm this result, especially in Hispanic populations.

Saliva-induced coacervation of inverted aggregates of hexanol for simplifying human biomonitoring: Application to the determination of free bisphenols

Saliva is progressively becoming a useful alternative to urine and blood to assess human exposure to toxics in biomonitoring campaigns, because of its easy and stress-free collection by unskilled personnel. This evaluation is highly challenging owing to the large number of compounds and individuals involved. In this article, we propose a new strategy to simplify sample treatment in the human biomonitoring of toxics in saliva. It is based on the in situ formation of supramolecular solvents (SUPRASs) in the sample. For this purpose, SUPRASs were produced in colloidal suspensions of aggregates of hexanol in THF under the addition of saliva, which played the dual role of inductor of the self-assembly process leading to SUPRAS formation and the sample to be analysed. The SUPRAS formation region was delimited from the phase diagram constructed for the ternary mixture saliva/hexanol/THF. An equation was derived for predicting the volume of SUPRASs produced as a function of the proportion of their components. The new strategy was explored for simplifying sample treatment in the biomonitoring of thirteen free bisphenol analogues and derivatives by liquid chromatography tandem mass spectrometry. Absolute recoveries for bisphenols were in the range 95–105.6%, the method was interference free (signal suppression/enhancement was between 93 and 106%), and the repeatability and within laboratory reproducibility were in the intervals 0.6–10% and 2–16%, respectively. The proposed method was fully validated and it was applied to the determination of the target bisphenols in saliva from 13 volunteers. Free bisphenol A was found in all samples (0.057–0.8 μg L−1), and bisphenol F, bisphenol S and bisphenol AF were found with a frequency of detection of 46%, 62% and 8%, respectively. So, saliva can be a suitable biological sample for studying human exposure to bisphenols. To the best of our knowledge, this is the first report dealing with the use of saliva for biomonitoring human exposure to bisphenols.

Free bisphenol A (BPA), BPA-Glucuronide (BPA-G), and total BPA concentrations in maternal serum and urine during pregnancy and umbilical cord blood at delivery

Abstract While adult exposure to total bisphenol A (BPA) has been well documented, developmental exposure to BPA and fetal exposure to the bioactive form (free BPA) remains poorly defined. Therefore, pregnant women (n = 199) between 28 and 35 weeks of pregnancy were invited to participate in this study. Maternal serum free of hemolysis (n = 189) and urine (n = 112) were collected at third trimester and delivery along with umbilical cord blood (UCB) at delivery. Free BPA, BPA mono-glucuronide (BPA-G) and total BPA concentrations were measured using gas chromatography coupled with tandem mass spectrometry. Circulating concentrations of free BPA were quantifiable above the method detection limit (MDL = 0.026 ng/mL) in approximately 34% of serum samples in the third trimester and 21% of samples at delivery whereas BPA-G and total BPA were quantified in 43 and 70% of third trimester and delivery samples, respectively. The geometric mean of free BPA, BPA-G and total BPA concentrations in maternal serum during the third trimester and at delivery were 0.62 ng/L and

Molecularly imprinted electrochemical aptasensor for the attomolar detection of bisphenol A.

Gold nanoparticles (AuNPs) were electrodeposited on the surface of a glassy carbon electrode (GCE) and then treated with a mixture of a thiolated DNA sequence (p-63; with high affinity for bisphenol A) and free bisphenol A (BPÀ). Pyrrole was then electropolymerizaed on the surface of the GCE to entrap the BPA@p-63 complex. BPA is then extracted with acetic acid solution to obtain MIP cavities where the embedded DNA sequence acts as the binding site for BPA. Scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were employed to characterize the surface of the modified GCE. Under the optimum conditions, the assay has a dynamic range that covers the 0.5fM to 5pM BPA concentration range and an 80aM detection limit. It was applied to the quantitation of BPA in (spiked) milk, milk powder and water samples and gave acceptable recoveries. Graphical Abstract Schematic of the procedure for aptamer-based detection of BPA using unique features of the aptamer-based modified electrodes and MIP-based sensors. This assay has high sensitivity and good selectivity. It can presumably be transferred to other detection schemes forsmall molecules.

Control of the epoxy resin curing process according to the free bisphenol A content by TLC

В контроле процесса отверждения эпоксидной смолы марки ЭД-20 использовали методику определения в ней свободного бисфенола А ( БФА ) с помощью ТСХ в сочетании с цифровой цветометрией ( ЦЦМ ). Для проявления хроматографических пятен БФА применяли две цветных реакции. По цветометрическим параметрам двух электронных изображений проявленных пятен в цветовой модели RGB строили лепестковые диаграммы ( ЛД ), геометрические параметры которых (площадь, периметр, форма) зависят от природы и концентрации аналита. В исследованиях использовали отвердители аминного типа – полиэтиленполиамин (ПЭПА) и Этал–45М. Формальная кинетика превращений БФА в реакционной массе удовлетворительно подчиняется уравнению первого порядка. В ходе реакции отверждения смолы ЭД-20 отвердителем ПЭПА при 100 о С период полупревращения БФА равен ~ 14 минутам, а при использовании Этал-45М при 50 о С он сокращается до ~ 6 минут. Контроль отверждения осуществляли также методом ИК-спектроскопии. Этот метод позволяет контролировать изменение содержания в смоле эпоксидных групп по изменению оптической плотности характеристических полос (915 см -1 ), но недостаточно эффективен в контроле содержания групп ‒ОН фенольного типа. Данные, полученные методом ТСХ в тандеме с ЦЦМ, хорошо дополняют ИК-спектроскопическую информацию, демонстрируют высокую специфичность методики по отношению к группам ‒OH фенольного типа, что позволяет контролировать содержание свободного БФА в образцах отвержденных эпоксидных смол. Ключевые слова : бисфенол А, тонкослойная хроматография (ТСХ), ИК-спектроскопия, цифровая цветометрия, эпоксидная смола DOI: http://dx.doi.org/10.15826/analitika.2017.21.2.004

Cord blood insulin-like peptide 3 is reduced in idiopathic cryptorchidism and inversely related to free bisphenol A: a marker and/or an actor of foetal exposure to endocrine disruptors?

Cord blood insulin-like peptide 3 is reduced in idiopathic cryptorchidism and inversely related to free bisphenol A: a marker and/or an actor of foetal exposure to endocrine disruptors?

Serial Free Bisphenol A and Bisphenol A Glucuronide Concentrations in Neonates

To determine the balance of metabolism of free bisphenol A (BPA) to the inactive conjugate, BPA glucuronide (BPAG), in neonates. Free BPA and BPAG concentrations were measured in 78 urine samples collected between December 2012 and August 2013 from a cohort of 44 healthy full term (≥ 37 weeks' gestation) neonates at 2 intervals (3-6 days and 7-27 days of age). A questionnaire was administered at the time of sample collection. Neonates recruited into the study were born in an urban, tertiary care hospital. Only BPAG was detected in the urine samples; concentrations ranged from <0.1 μg/L to 11.21 μg/L (median: 0.27 μg/L). Free BPA concentrations were below the limit of quantification of 0.1 μg/L. Age, but not sex or type of diet, was significantly associated with urinary BPAG concentration (P = .002). Our results illustrate widespread BPA exposure in healthy full-term neonates and efficient conjugation of BPA to its readily excretable and biologically inactive form (BPAG) as early as 3 days of age. Factors other than type of diet may be important contributors to BPA exposure in neonates.

Report on the two‐phase public consultation on the draft EFSA scientific opinion on bisphenol A (BPA)

Report on the two‐phase public consultation on the draft EFSA scientific opinion on bisphenol A (BPA)

A negative correlation between insulin-like peptide 3 and bisphenol A in human cord blood suggests an effect of endocrine disruptors on testicular descent during fetal development.

Does a relationship exist between insulin-like peptide 3 (INSL3) and selected environmental endocrine disruptors (EEDs) in human cord blood (cb)? In the whole population (cryptorchid and control boys) cbINSL3 correlated negatively with cb free bisphenol A (BPA) providing indirect evidence for an impact of EEDs on fetal Leydig cell INSL3 production. INSL3 is a major regulator of testicular descent. This hormone has been shown to be decreased in cord blood from boys with idiopathic cryptorchidism, the most frequent male malformation. Fetal exposure to several EEDs has been suspected to be involved in the occurrence of idiopathic cryptorchidism. Correlations between cb INSL3 or testosterone and cb free bioactive BPA and maternal milk polychlorinated biphenyls (PCB153), dichlorodiphenyldichloroethylene (DDE), and monobutyl phthalate (mBP) were assessed in newborn boys in a prospective case-control study. All boys (n = 6246) born after 34 weeks of gestation were systematically screened at birth for cryptorchidism over a 3-year period (2002-2005), and a diagnosis of cryptorchidism confirmed by a senior paediatrician. We studied 52 cryptorchid (26 transient, 26 persistent) and 128 control boys born at two hospitals in southern France. INSL3 was assayed in CB by a modified validated enzyme-linked immunosorbent assay. Testosterone was measured in CB after diethyl-ether extraction by means of ultra-pressure liquid chromatography-tandem mass spectrometry. Free cbBPA was measured after an extraction step with a radioimmunoassay validated after comparison of values obtained by high-pressure liquid chromatography-mass spectrometry. The xenobiotic analysis in mothers' milk was performed after fat extraction by gas chromatography-mass spectrometry. EED concentrations were not increased in the cryptorchid versus control group although a trend for increased mBP (P = 0.09) was observed. In the whole study population, cb levels of BPA correlated negatively with INSL3 (P = 0.01; R² = 0.05) but not with testosterone. No other EED correlated with INSL3 or with testosterone. The levels of BPA and INSL3 in cb may not reflect chronic fetal exposure to EEDs. The deleterious impact of EEDs on fetal testicular descent during specific windows of development has yet to be demonstrated. The negative correlation between cb free BPA and INSL3 provides indirect evidence for an impact of EEDs on human fetal Leydig cell INSL3 production and points to cbINSL3 as a possible target of EED action during fetal testis development.

Urinary Free Bisphenol a and Bisphenol a Glucuronide Concentrations in a Sample of Neonates in Baltimore, Maryland

Background: Bisphenol A (BPA) exposure is widespread in the general population. Public health concerns stem from its estrogenic properties. Poor glucuronidation capacity at birth may impede its conjugation to BPA glucuronide, a biologically inert form. Aim: To determine the impact of poor glucuronidation capacity on BPA toxicokinetics in healthy full-term neonates. Methods: Mothers and healthy full-term neonates were recruited at the Johns Hopkins Hospital in Baltimore, Maryland from December 2012 to July 2013. Urine samples were collected and a questionnaire administered at ages 3-6 and 7-28 days. A quality control protocol was implemented to reduce contamination of samples with BPA from field and laboratory sources. Free BPA and BPA glucuronide concentrations were quantified by high performance liquid chromatography, tandem mass spectrometry with dansyl chloride derivatization (LOQ=0.1 ug/L). BPA glucuronide concentrations were adjusted for the difference in the molecular weights of free BPA and BPA glucuronide. Results: BPA glucuronide was quantified in 71% of 78 urine samples from 44 neonates. No free BPA concentrations exceeded the LOQ in any sample. BPA glucuronide concentrations were higher at age 3-6 days (geometric mean: 0.25 ug BPA/L) than at age 7-28 days (geometric mean: 0.11 ug BPA/L). In a linear regression analysis that accounted for within-person correlation of BPA glucuronide concentrations (?=0.46), age group (ß=-0.5 [95% CI: -0.94, -0.06]) and breastfeeding (ß=-0.72 [95% CI: -1.4, -0.06]) were significantly associated with a decrease in urinary BPA glucuronide. Conclusions: Quantification of BPA glucuronide in these samples demonstrates exposure to and efficient glucuronidation of BPA during the neonatal period among healthy full-term neonates aged 3-6 and 7-28 days. These data include the first urinary BPA measurements in healthy full-term neonates in the first week of life. Formula intake may be a risk factor for BPA exposure.