Automated on-line liquid chromatography–photodiode array–mass spectrometry method with dilution line for the determination of bisphenol A and 4-octylphenol in serum

Exposure, toxicological mechanism of endocrine disrupting compounds and future direction of identification using nano-architectonics

Endocrine-disrupting compounds (EDC) are a group of exogenous chemicals that structurally mimic hormones and interfere with the hormonal signaling cascade. EDC interacts with hormone receptors, transcriptional activators, and co-activators, altering the signaling pathway at both genomic and non-genomic levels. Consequently, these compounds are responsible for adverse health ailments such as cancer, reproductive issues, obesity, and cardiovascular and neurological disorders. The persistent nature and increasing incidence of environmental contamination from anthropogenic and industrial effluents have become a global concern, resulting in a movement in both developed and developing countries to identify and estimate the degree of exposure to EDC. The U.S. Environment Protection Agency (EPA) has outlined a series of in vitro and in vivo assays to screen potential endocrine disruptors. However, the multidisciplinary nature and concerns over the widespread application demand alternative and practical techniques for identifying and estimating EDC. The review chronicles the state-of-art 20 years (1990-2023) of scientific literature regarding EDC's exposure and molecular mechanism, highlighting the toxicological effects on the biological system. Alteration in signaling mechanisms by representative endocrine disruptors such as bisphenol A (BPA), diethylstilbestrol (DES), and genistein has been emphasized. We further discuss the currently available assays and techniques for in vitro detection and propose the prominence of designing nano-architectonic-sensor substrates for on-site detection of EDC in the contaminated aqueous environment.

Immunosuppression participated in complement activation-mediated inflammatory injury caused by 4-octylphenol via TLR7/IκBα/NF-κB pathway in common carp (Cyprinus carpio) gills

4-octylphenol (4-OP), a toxic estrogenic environmental pollutant, can threaten aquatic animal and human health. However, toxic effect of 4-OP on fish has not been reported. To investigate molecular mechanism of gill poisoning caused by 4-OP exposure, a carp 4-OP poisoning model was established, and then blood and gills were collected on day 60. The results demonstrated that gill was a target organ attacked by 4-OP, and exposure to 4-OP caused carp gill inflammatory injury. There were 1605 differentially expressed genes (DEGs, including 898 up-regulated DEGs and 707 down-regulated DEGs). KEGG and GO were used to further analyze obtained 1605 DEGs, indicating that complement activation, immune response, and inflammatory response participated in the mechanism of 4-OP-caused carp gill inflammatory injury. Our data at transcription level further revealed that 4-OP caused complement activation through triggering complement component 3a/complement component 3a receptor (C3a/C3aR) axis and complement component 5a/complement component 5a receptor 1 (C5a/C5aR1) axis, induced immunosuppression through the imbalances of T helper (Th) 1/Th2 cells and regulatory T (Treg)/Th17 cells, as well as caused inflammatory injury via toll like receptor 7/inhibitor kappa B alpha/nuclear factor-kappa B (TLR7/IκBα/NF-κB) pathway. Taken together, immunosuppression participated in complement activation-mediated inflammatory damage in carp gills after 4-OP treatment. The findings of this study will provide pioneering information and theoretical support for the mechanism of 4-OP poisoning, and will provide reference for the assessment of estrogenic environmental pollution risk.

First report on occurrence of bisphenol A isomers in human serum and whole blood

Studies have demonstrated the worldwide presence of bisphenol A (BPA) and its toxic effects on human health. BPA may exist as several structural isomers, which are byproducts in industrial BPA production. However, nearly nothing is known about the occurrence of BPA isomers in human blood and the partitioning of BPA metabolites between human serum and whole blood. In this study, BPA, BPA-sulfate (BPA-S), and BPA-glucuronide (BPA-G) were quantified in 144 pairs of serum and whole blood samples from Chinese participants. BPA was detected in 115 serum and 121 whole blood samples, with mean concentrations of 0.53 and 0.88 ng/mL, respectively. A structural isomer of BPA, tentatively termed B₁-BPA, was identified for the first time, and measurable in 53% and 57% of serum (<LOD-1.9 ng/mL) and whole blood (<LOD-1.4 ng/mL) samples, respectively. BPA-S was the predominant BPA metabolite (mean 2.3 and 1.4 ng/mL, respectively), significantly higher (p < 0.01) than BPA-G (1.3 and 0.64 ng/mL) in both serum and whole blood. The calculated partitioning coefficients between serum and whole blood were the highest for B₁-BPA (mean ± SD, 1.8 ± 0.25), followed by BPA-S (1.6 ± 0.36), BPA-G (1.4 ± 0.37), and BPA (1.3 ± 0.39), indicating their preferential enrichment in the serum fraction. Overall, this study first identifies a BPA isomer, which has not been previously reported in any environmental or human samples. Measuring BPA isomers in human serum and whole blood is critical for accurate human BPA exposure risk assessment.

Association of endocrine disrupting chemicals levels in serum, environmental risk factors, and hepatic function among 5- to 14-year-old children

Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during childhood, however, the association among the exposure level of EDCs such as Nonylphenol (NP), Bisphenol A (BPA), Dimethyl phthalate (DMP) in children and environmental risk factors, as well as hepatic function has not been elaborated. This study aimed to discuss this interesting relationship among NP, BPA, DMP concentrations in serum, environmental risk factors, hepatic function of 5- to 14-year-old children in industrial zone, residential zone and suburb in northern district of Guizhou Province, China. In Zunyi city, 1006 children participated in cross-sectional health assessments from July to August 2018, and their parents completed identical questionnaires on the environmental risk factors of EDCs exposure to mothers and children. Serum NP, BPA and DMP concentrations were measured by high performance liquid chromatography (HPLC). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ALT, total bilirubin (TBIL), direct bilirubin (DBIL) and indirect bilirubin (IBIL) were detected with automatic biochemical analyzer. The median concentrations of serum NP, BPA, and DMP in the participants were 45.85 ng/mL, 26.31 ng/mL and 31.62 ng/mL, respectively, which were higher than the environmental concentration limits of the U.S. National Environmental Protection Agency (EPA). Hair gels used during pregnancy, types of domestic drinking water, nail polish and cosmetics used by children were significantly positive correlated with serum NP concentration (P < 0.05). Gender, feeding pattern, plastic water cup used during pregnancy, hair spray and perfume use for children, duration of children birth, materials for baby bottle or cup and ways to plastic products were significantly positively correlated with serum BPA concentration (P < 0.05). Gender, perms used during pregnancy, hair spray and perfume use for children, using plastic lunch box during pregnancy, duration of children birth, exposure to pesticides, parents' occupations were significantly positively correlated with serum DMP concentrations (P < 0.05). Serum NP (β = 0.296, P = 0.036) and DMP (β = 0.316, P = 0.026) concentrations and TBIL level were significantly positively correlated. Serum NP concentration and the levels of IBIL (β = 0.382, P = 0.006) are significantly positively correlated. Cosmetics used during pregnancy significantly increased AST level (β = 2.641, P = 0.021). There was a positive correlation between the frequency of hair spray and perfume use for children and the AST (β = 4.241, P = 0.022). NP, BPA and DMP, which were commonly detected in the serum of children aged 5-14 years old in Zunyi City, Northern Guizhou Province, China, were closely related to the environmental risk factors of exposure environment during pregnancy, infancy and school age. Exposure to NP, BPA and DMP would have negative effects on hepatic function, and these effects showed differences in gender and geographical location. Notably,The relationships were more evident in girls than in boys.

Oxidative Stress, Endocrine Disturbance, and Immune Interference in Humans Showed Relationships to Serum Bisphenol Concentrations in a Dense Industrial Area

Bisphenol A (BPA) analogues, used in a range of products due to health concerns regarding BPA, have emerged as ubiquitous environmental contaminants worldwide. This study aims to evaluate the levels of nine bisphenols (BPs) and eight biomarkers (malondialdehyde, MDA; 8-hydroxy-2'-deoxyguanosine, 8-OHdG; estradiol, E2; follicle-stimulating hormone, FSH; luteinizing hormone, LH; complement compound 3, C3; immunoglobulin M, IgM and c-reaction protein, CRP) in human serum (n = 353) to explore their potential relationships. The detection rates (DRs) of eight BPs in serum samples taken from people working in a dense industrial area of Shenzhen (Guangdong Province, China) were over 72% except for bisphenol B (BPB) (DR = 27.5%). The mean concentrations of BPA, bisphenol P (BPP), BPB, bisphenol F (BPF), bisphenol FL (BPFL), 4,4'-dihydroxy-benzophenone (DHBP), bisphenol AF (BPAF), 4,4'-thiodiphenol (TDP) and bisphenol S (BPS) were 42.062, 2.083, 0.765, 0.578, 0.423, 0.402, 0.191, 0.120, and 0.071 ng/mL, respectively. BPA and BPFL were significantly correlated with the level of oxidative stress indices MDA and 8-OHdG; BPAF, BPB, and DHBP were strongly correlated with the level of endocrine disturbance indices E2, FSH, and LH; and BPF, DHBP, and BPAF were apparently related to the level of immune interference indices C3 and IgM. This study also suggests multiple impacts (oxidative stress, endocrine disturbance, and immune interference) mediated by BPs contaminants in vivo. To our knowledge, this is the first study to report the correlations among these nine serum BPs and oxidative stress and endocrine and immune system indices in human serum samples collected from dense industrial areas.

In Situ Determination of Bisphenol A in Beverage Using a Molybdenum Selenide/Reduced Graphene Oxide Nanoparticle Composite Modified Glassy Carbon Electrode

Due to the endocrine disturbing effects of bisphenol A (BPA) on organisms, rapid detection has become one of the most important techniques for monitoring its levels in the aqueous solutions associated with plastics and human beings. In this paper, a glassy carbon electrode (GCE) modified with molybdenum selenide/reduced graphene oxide (MoSe₂/rGO) was fabricated for in situ determination of bisphenol A in several beverages. The surface area of the electrode dramatically increases due to the existence of ultra-thin nanosheets in a flower-like structure of MoSe₂. Adding phosphotungstic acid in the electrolyte can significantly enhance the repeatability (RSD = 0.4%) and reproducibility (RSD = 2.2%) of the electrode. Under the optimized condition (pH = 6.5), the linear range of BPA was from 0.1 μM⁻100 μM and the detection limit was 0.015 μM (S/N = 3). When using the as-prepared electrode for analyzing BPA in beverage samples without any pretreatments, the recoveries ranged from 98⁻107%, and the concentrations were from below the detection limit to 1.7 μM, indicating its potential prospect for routine analysis of BPA.

Occurrence and Partitioning of Bisphenol Analogues in Adults' Blood from China

Widespread human exposure and associated adverse health effects led to regulations on the usage of bisphenol A (BPA). Several bisphenol analogues (BPs) have been introduced as BPA alternatives in various applications. However, these BPs have been shown to exhibit similar or even stronger endocrine-disrupting activities compared with that of BPA. Currently, information on the human exposure to BPA alternatives remains limited. In this study, nine BPs were quantified in 81 pairs of plasma and red blood cell (RBC) samples from Chinese participants. In human plasma, the predominant BPs was BPA, bisphenol S (BPS), and bisphenol AF (BPAF), with the mean concentrations of 0.40, 0.15, and 0.073 ng/mL, respectively. BPA (accounting for 63% of total BPs) and BPS (18%) were the major BPs in the RBC fraction. Mass fractions in plasma (F_p) were found to be highest for BPS (mean, 0.78), followed by BPAF (0.71) and BPA (0.67), indicating strong partitioning to the plasma fraction. However, bisphenol AP was more frequently detected in the RBC fraction. Estimated total daily intake (EDI) of BPA was in the range of 0.0048-0.75 μg/kg bw/day for the participants, and adults aged >50 years had comparatively lower EDI. To our knowledge, this is the first study to assess the occurrence and partitioning of BPA alternatives in paired human plasma and RBCs from the Chinese general population.

Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for Bisphenol A

A simple and effective strategy for designing a ratiometric fluorescent nanosensor is described in this work. A carbon dots (CDs) based dual-emission nanosensor for Bisphenol A (BPA) was prepared by coating CDs on the surface of dye-doped silica nanoparticles. The fluorescence of dual-emission silica nanoparticles was quenched in hydrochloric acid by potassium bromate (KBrO₃) oxidation; BPA inhibited KBrO₃ oxidation, resulting in the ratiometric fluorescence response of dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated and optimized. The detection limit of this nanosensor was 0.80ng mL^-1 with a linear range from 10 to 500ng mL^-1. This was applied successfully to determine BPA in the leached solution of different plastic products with satisfactory results.

Hormonally active agents in the environment: a state-of-the-art review

After the Second World War, infatuation with modern products has exponentially widened the spectrum of chemicals used. Some of them are capable of hijacking the endocrine system by blocking or imitating a hormone and are referred to as hormonally active chemicals or endocrine disruptors. These are chemicals that the body was not designed for evolutionarily and they are present in every matrix of the environment. We are living in a chemical world where the exposures are ubiquitous and take place in combinations that can interact with the endocrine system and some other metabolic activities in unexpected ways. The complexity of interaction of these compounds can be understood by the fact that they interfere with gene expression at extremely low levels, consequently harming an individual life form, its offspring or population. As the endocrine system plays a critical role in many biological or physiological functions, by interfering body's endocrine system, endocrine disrupting compounds (EDCs) have various adverse effects on human health, starting from birth defects to developmental disorders, deadly deseases like cancer and even immunological disorders. Most of these compounds have not been tested yet for safety and their effects cannot be assessed by the available techniques. The establishment of proper exposure measurement techniques and integrating correlation is yet to be achieved to completely understand the impacts at various levels of the endocrine axis.

Sensitive detection of bisphenol A based on a ratiometric electrochemical aptasensor

A new ratiometric electrochemical aptasensor has been developed for highly sensitive and selective detection of bisphenol A (BPA). The double-stranded DNA (dsDNA), consisting of the BPA aptamer (DNA1) and methylene blue (MB)-labeled complementary DNA (cDNA), was immobilized on a gold nanoparticle (AuNP) modified glassy carbon (GC) electrode. In the presence of BPA, the specific BPA–aptamer interaction drove the release of the MB-labeled cDNA from the electrode surface. As a result, the oxidation peak current of MB (IMB) decreased and that of BPA (IBPA) increased. The peak current ratio (IBPA/IMB) of BPA and MB was linear with the concentration of BPA in the range from 1 to 100 pmol/L with a detection limit of 0.6 pmol/L. The detection limit is much lower than that obtained by most of the reported electrochemical methods. On the other hand, the developed aptasensor possesses good selectivity, reproducibility, and stability, and the related sensing structure is very simple, showing promising practical applications in BPA assays.

A novel electrochemical aptasensor for bisphenol A assay based on triple-signaling strategy

Based on a triple-signaling strategy, a novel electrochemical aptasensor has been developed for sensitive and selective detection of bisphenol A (BPA). The thiolated ferrocene (Fc)-modified BPA-binding aptamer probe (Fc-P) was immobilized on the gold electrode and then hybridized with the methylene blue (MB)-modified complementary DNA probe (MB-P) to form a rigid double-stranded DNA (ds-DNA). The specific interaction between BPA and Fc-P led to the release of MB-P from the sensing interface and the conformational change of Fc-P. As a result, the oxidation peak currents of Fc and BPA increased with the increase of the concentration of target (BPA) according to the "signal-on" mode while that of MB decreased with the increase of the BPA concentration according to the "signal-off" mode. By superimposing the triple signal changes, BPA was detected sensitively with a linear range from 1 pM to 100 pM. The detection limit is 0.19 pM, and much lower than that obtained by most of the reported electrochemical methods. The aptasensor also exhibited satisfactory specificity, selectivity, reproducibility and stability. By changing the specific aptamers, this strategy could be easily extended to detect other redox targets, showing promising applications in environmental analysis, food safety monitoring, and bioanalysis.

Global Assessment of Bisphenol A in the Environment: Review and Analysis of Its Occurrence and Bioaccumulation

Because bisphenol A (BPA) is a high production volume chemical, we examined over 500 peer-reviewed studies to understand its global distribution in effluent discharges, surface waters, sewage sludge, biosolids, sediments, soils, air, wildlife, and humans. Bisphenol A was largely reported from urban ecosystems in Asia, Europe, and North America; unfortunately, information was lacking from large geographic areas, megacities, and developing countries. When sufficient data were available, probabilistic hazard assessments were performed to understand global environmental quality concerns. Exceedances of Canadian Predicted No Effect Concentrations for aquatic life were >50% for effluents in Asia, Europe, and North America but as high as 80% for surface water reports from Asia. Similarly, maximum concentrations of BPA in sediments from Asia were higher than Europe. Concentrations of BPA in wildlife, mostly for fish, ranged from 0.2 to 13 000 ng/g. We observed 60% and 40% exceedences of median levels by the US Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey in Europe and Asia, respectively. These findings highlight the utility of coordinating global sensing of environmental contaminants efforts through integration of environmental monitoring and specimen banking to identify regions for implementation of more robust environmental assessment and management programs.

Quantitative Analysis of Chloramphenicol in Royal Jelly by Column-switching LC-MS/MS Using a Pretreatment Column with a Higher-pressure Capability

An on-line pretreatment liquid chromatography-tandem mass spectrometry (LC-MS/MS) system was developed for the analysis of chloramphenicol (CAP) in royal jelly. A novel methylcellulose-immobilized restricted access media column with a higher-pressure capability of 60 MPa (MC-ODS HP) was developed for the effective removal of proteins and other compounds in the sample matrix. CAP in a sample solution was extracted in 2 min by the column-switching LC-MS/MS system. The system provides a minimum sample pretreatment along with highly sensitive and reproducible analysis. As a result, the limit of quantitation of CAP was 10 pg/mL (= 0.1 μg/kg royal jelly) and the linear dynamic range was between 10 and 10000 pg/mL (correlation coefficient greater than 0.999). The proposed method meets the requirements of regulations in EU (0.3 μg/kg). The inter-day precision and accuracy of CAP at 100 pg/mL over 3 days were 4.5 and 95.4%, respectively. Compared with the conventional method with a pressure of below 25 MPa, the peak separation in the MRM chromatogram was improved by using smaller particles (1.6 μm) for the analytical ODS column. The LC-MS/MS system with an MC-ODS HP expanded the applicability of the automated pretreatment.

Detection of bisphenol A in food packaging based on fluorescent conjugated polymer PPESO3 and enzyme system

Bisphenol A (BPA) is a kind of carcinogen, which can interfere with the body's endocrine system. In this paper, a new kind of fluorescent sensor for BPA detection was established based on the fluorescent conjugated polymer PPESO3. The oxidative product of BPA is able to quench PPESO3 in the presence of HRP and H2O2, and the quenched PL intensity of PPESO3 was proportionally to the concentration of BPA in the range of 1-100 μmol/L with a detection limit of 4 × 10(-7) mol/L. The proposed method has been applied to detect BPA in eight food packaging samples with satisfactory results. The proposed method has the potential for the assay of BPA in food or food packaging samples.

A portable optic fiber aptasensor for sensitive, specific and rapid detection of bisphenol-A in water samples

Bisphenol A (BPA) is a known endocrine disruptor and one of the most serious environmental contaminants, often present at low levels in various water sources. Therefore, it is very important and necessary to develop a fast, cost-effective, sensitive, and selective method for on-site detection of BPA. Herein, we developed a portable, evanescent, wave fiber-optic aptasensor for rapid, on-site detection of BPA with high sensitivity and selectivity. In this system, the probe DNA molecule, which is the complementary sequence of a small part of the BPA aptamer, was covalently immobilized onto the optical fiber sensor surface. Using an indirect competitive detection mode, samples containing different concentrations of bisphenol A were premixed with a given concentration of fluorescence-labeled BPA aptamer, which binds to bisphenol A with high specificity. Then, the sample mixture was pumped to the sensor surface, and a higher concentration of BPA led to less fluorescence-labeled BPA aptamer hybridized with surface immobilized probe DNA and thus to a lower fluorescence signal. The developed sensing system exhibits a sensitive response to BPA in the range of 2 nM to 100 nM with a low detection limit of 1.86 nM (0.45 ng ml(-1)) under the optimal conditions. The biosensors showed good reproducibility, stability, and selectivity for BPA detection. Finally, this proposed sensor was successfully employed to determine the presence of BPA in wastewater samples.

Alternative sample diluents in bioanalytical LC–MS

The problem of sample diluent in bioanalytical LC–MS is reviewed with a special focus on large-volume injections and non-miscible solvents with mobile phase components. These issues are related to the sample preparation approach, which in many instances provides the sample diluent before injecting this into the chromatographic column. The sample volume influences the quantitation limit of the chromatographic method, while its nature may influence the retention process of the injected analytes. The literature reports a few papers that are focused on alternative sample diluents in bioanalytical LC–MS that are generally non-miscible with mobile phase. The principle of this approach and some of its current bioanalytical applications from literature are discussed. However, more applications and more publications from HPLC users and vendors are expected in this field, which could prove its analytical importance and potential in bioanalysis.

[Impact of endocrine disrupting chemicals on birth outcomes]

BACKGROUND

Endocrine disruptors are ubiquitous chemicals contaminants in the environment, wildlife, and humans. Their adverse effects on reproduction are well-documented. There is growing evidence that they can contribute to the current emergence of chronic diseases.

OBJECTIVES

Our aim is to assess the relationships between endocrine disruptors and the neonatal health outcomes.

METHODS

Two persons have independently reviewed Medline and Toxline databases about the following pollutants: bisphenol A, phthalates, parabens, brominated flame retardants and perfluorinated compounds. Only the human epidemiological studies, in general population with an abstract available, published between 2007 January the 1st and 2011 December the 31st, were analysed. The quality of each study was assessed with the Strobe score.

RESULTS

Twenty-five out of 680 studies were included in the analysis. All pollutants were widely detected in maternal and new borns samples. Most of the studies have shown associations between bisphenol A, brominated flame retardants and perfluorinated compounds and lower birth weight. The effects on gestational age were less documented and have shown no clear connection. Results for phthalates were more ambiguous. Only one non-instructive study was found on parabens.

DISCUSSION

Due to the inherent methological bias on endocrine disruptors research, further additional studies on environmental health must be investigated. It seems necessary to adopt preventive health measures first for vulnerable population.

A novel method for the quantitative determination of free and conjugated bisphenol A in human maternal and umbilical cord blood serum using a two-step solid phase extraction and gas chromatography/tandem mass spectrometry

Bisphenol A is widely used as a monomer in the manufacture of polycarbonates and epoxy resins, as an antioxidant in polyvinyl chloride (PVC) plastics and as an inhibitor of end polymerisation in PVC. Several different methods have been used to quantify total BPA in biological specimens. However, quantification of both free and conjugated BPA continues to present challenges. Moreover, there is limited data concerning fetal exposure. Therefore, the objective of this study was to develop a new method for the analysis of both free and conjugated BPA in human maternal and umbilical cord blood serum. For the analysis of free BPA, the method consisted of a liquid-liquid extraction followed by a two-step solid-phase extraction sample cleanup on Florisil and Oasis HLB sorbents, derivatization of the extract using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and analysis by gas chromatography/tandem mass spectrometry (GC/EI-MS/MS). To determine the amount of conjugated BPA in serum samples, bisphenol A-d6 β-glucuronide (4-[1-(4-hydroxyphenyl)-1-methylethyl-d6]phenyl β-D-glucopyranosiduronic acid) was added to each sample prior to enzymatic deconjugation. The MDL and LOQ for BPA were 0.026 ng/mL and 0.087 ng/mL, respectively. The observed recoveries ranged between 65% and 88%. The new method was applied to the determination of paired human maternal and umbilical cord blood serum samples. The results demonstrated that total BPA concentrations in human maternal serum at mid-pregnancy and at delivery ranged from <0.026 ng/mL to 10.425 ng/mL (median 0.548 ng/mL, n=12) and <0.026 ng/mL to 3.048 ng/mL (median 1.461 ng/mL), respectively. Results for matching umbilical cord blood serum BPA concentrations were in the range of <0.026-2.569 ng/mL (median 1.823 ng/mL). The concentrations measured in this study agreed well with BPA levels in human serum reported internationally. Only 2 mid-pregnancy serum samples out of 12 contained quantifiable amounts of conjugated BPA, indicating that BPA-glucuronide is not abundant in either human maternal or umbilical cord blood serum.

Circulating levels of bisphenol A (BPA) and phthalates in an elderly population in Sweden, based on the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS)

The plastic manufacture compounds, bisphenol A (BPA) and phthalates, are ubiquitous and have therefore been detected in virtually all types of analyzed human samples. The aim of this study was: (1) to investigate concentrations of serum levels of BPA and phthalate metabolites in seniors residing in the city of Uppsala, Sweden (2) to evaluate gender differences in relation to serum levels of BPA and phthalate metabolites in the subjects. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), encompassing 1016 subjects, all aged 70, serum levels of BPA and phthalate metabolites were measured by Isotope Dilution-High Performance Liquid Chromatography-Tandem Mass Spectrometry. BPA and four out of ten phthalate metabolites, namely, Monoisobutyl phthalate (MiBP), Monomethyl phthalate (MMP), Monoethyl phthalate (MEP), Mono-(2-ethylhexyl) phthalate (MEHP), were detectable in almost all subjects. Of the remaining phthalate metabolites, Monobenzyl phthalate (MBzP), Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MeHHP), and Mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) were seen in some 300-700 of the subjects, whereas Monoisononyl phthalate (MINP) and Mono-n-octyl phthalate (MOP) were found in only a few and Monocyclohexyl phthalate (MCHP) was not detected in any subject. Neither the circulation levels of BPA nor those of phthalate metabolites differ between the genders in this elderly population of residents in Uppsala, Sweden.

A simple, sensitive, rapid and specific detection method for Bisphenol A based on Fluorescence Polarization Immunoassay

A rapid, sensitive, specific and simple method based on Fluorescence Polarization Immunoassay (FPIA) was developed for the quantitative detection of Bisphenol A in water. 4, 4-Bis (4-hydroxyphenyl) valeric acid (BHPVA) was selected as the hapten to produce the immunogen. Fluorescein-labeled Bisphenol A derivatives (tracers) with different structures were synthesized and purified by thin layer chromatography. Based on the polyclonal antibody and tracers, an optimized FPIA method was developed with a detection limit (10% inhibition) of 2 μg L(-1) and a linear working range of 20 to 800 μg L(-1). FPIA was suitable for screening a large number of samples. The recoveries of fortified Tai lake water samples ranged from 91.85 to 102.78%, and tap water samples ranged from 90.36 to 96.01%. The coefficients of variation were all less than 20%. This FPIA method, which did not require a complicated cleanup process, proved to be very useful for the screening of Bisphenol A in environmental water samples.

Alkylphenols in adipose tissues of Italian population

Alkylphenols (APs) and AP ethoxylated compounds (APEs) were screened in human subcutaneous adipose tissue samples from Italy. The samples were collected during bariatric surgery from 16 subjects (three men and 13 women) and a total of seven alkylphenol compounds (APs) was detected. Nonylphenol (NP) was the compound found at the highest level (mean 122 ng g⁻¹ fresh weight; range 10-266 ng g⁻¹ fw). Several nonylphenol ethoxylates (NPEOs) were found in all the sample analysed though the frequency of detection decreased with the increasing number of ethoxylic groups. NP4EO was found only in four patients ranging from trace amounts to 41.3 ng g⁻¹ fw. Total nonylphenols (NPEs) ranged between 45 and 1131 ng g⁻¹ fw, whereas the concentration of total octylphenols (OPEs) was at least 10 times lower (range 6-80 ng g⁻¹ fw). Our findings show that the average concentration of NP is about two times higher than that found in women from Southern Spain and up to three times that of people from Switzerland. Similarly, OP mean level is two times that reported in Finland and Spain populations. This is the first study that reports the presence of alkylphenols in the Italian population adipose tissue and it draws a baseline for further researches in order to depict a trend in human exposure to these compounds and to investigate possible consequences for human health.

Determination of endocrine disruptors in honey by CZE-MS using restricted access materials for matrix cleanup

An analytical method based on CZE coupled to ESI-MS is proposed for the identification and simultaneous quantification of several endocrine-disrupting chemicals in honey. The target compounds were the chlorophenols: 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol, and bisphenol-A, 4-tert-butylphenol, and 4-tert-butylbenzoic acid. A two-step optimization of the ESI-MS detection was carried out. First, the organic solvent present in the sheath liquid was selected and its effect on the analytical signal was studied. The best results in terms of the intensity of the MS signals were obtained with methanol. Thus, an experimental design technique (Doehlert type) was used for the optimization of the other parameters: the NH(3) concentration in the sheath liquid, the flow of the sheath liquid, the nebulizer pressure in ESI, and the drying gas temperature and flow. Here, we developed a new sample treatment based on the combined use of a restricted access material and a polymeric sorbent for SPE. The LOD achieved were in the range of 5-31 ng/g. The intraday precision of the proposed method was determined from replicate analyses (n=4) at a concentration level of 50 ng/g, with RSD values in the range of 15-23%. The results revealed that the proposed method is suitable for the reliable quantification of endocrine-disrupting chemicals in honey at nanograms per gram levels.

Recent advances in mass spectrometry analysis of phenolic endocrine disruptors and related compounds

This article reviews recent literature on current methodologies based on chromatography coupled to mass spectrometry to analyze phenolic compounds with endocrine-disrupting capabilities. For this review we chose alkylphenol ethoxylates, bisphenol A, bisphenol F, and their degradation products and halogenated derivatives, which are considered important environmental contaminants. Additionally, some related compounds such as bisphenol diglycidylethers were included. Growing attention has been paid to the mass spectrometric characterization of these compounds and the instrumentation and strategies used for their quantification and confirmation. The current use of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) methodologies with different mass spectrometers and ionization and monitoring modes is discussed. Practical aspects with regards to the use of these analytical techniques, such as derivatizing reagents in GC-MS, ion suppression in LC-MS, and the most problematic aspects of quantification, are included in the discussion.

Urinary, circulating, and tissue biomonitoring studies indicate widespread exposure to bisphenol A

BACKGROUND

Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Thus, there are concerns that the amount of BPA to which humans are exposed may cause adverse health effects. Importantly, results from a large number of biomonitoring studies are at odds with the results from two toxicokinetic studies.

OBJECTIVE

We examined several possibilities for why biomonitoring and toxicokinetic studies could come to seemingly conflicting conclusions.

DATA SOURCES

We examined > 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxicokinetic studies of human BPA metabolism.

DATA EXTRACTION AND SYNTHESIS

The > 80 biomonitoring studies examined included measurements in thousands of individuals from several different countries, and these studies overwhelmingly detected BPA in individual adults, adolescents, and children. Unconjugated BPA was routinely detected in blood (in the nanograms per milliliter range), and conjugated BPA was routinely detected in the vast majority of urine samples (also in the nanograms per milliliter range). In stark contrast, toxicokinetic studies proposed that humans are not internally exposed to BPA. Some regulatory agencies have relied solely on these toxicokinetic models in their risk assessments.

CONCLUSIONS

Available data from biomonitoring studies clearly indicate that the general population is exposed to BPA and is at risk from internal exposure to unconjugated BPA. The two toxicokinetic studies that suggested human BPA exposure is negligible have significant deficiencies, are directly contradicted by hypothesis-driven studies, and are therefore not reliable for risk assessment purposes.

Nonylphenol and octylphenol in adipose tissue of women in Southern Spain

Alkylphenols (APs) and AP ethoxylates are environmental contaminants with endocrine disrupting activities in wildlife and humans. They have been largely used in industrial, agricultural, and domestic applications. Despite strong concerns about the consequences of human exposure to endocrine disrupters, little information is available on the presence in humans of compounds such as APs. The aim of the present study was to determine 4-nonylphenol (NP) and 4-octylphenol (OP) residues in adipose tissue of non-occupationally exposed women living in Southern Spain. NP was detected in 100% (n=20/20) and OP in 23.5% (n=4/20) of samples, with median levels of 57 and 4.5 ng g(-1) adipose tissue, respectively. Body mass index emerged as a determinant of exposure since it was associated with NP levels (p=0.041). Adipose tissue NP and OP levels are similar to the few data previously published in other countries. This is the first report on NP and OP levels in a population in Southern Spain. Further research is needed to determine trends in human exposure to these compounds and to investigate their consequences.

Restricted-access media supports for direct high-throughput analysis of biological fluid samples: review of recent applications

This review presents an update on the use of restricted-access materials (RAMs) for direct injection of biological samples. The fundamental improvements in the preparation of tailored RAMs and the diversity of applications with these phases are presented. Insights into diminishing the matrix effect by the use of RAM supports in methods by LC–MS and into the low number of methods for enantiomeric separations by direct injections of biological samples are addressed. The diversity of systems that incorporate RAMs for selective sample clean-up or fractionation in proteome and peptidome analysis is also covered.