BPA Residues Research Articles

Hexacyanoferrate (III)/copper-TMA metal–organic framework for ultra-sensitive detection of bisphenol A

We report the construction of Fe(CN)63--doped copper-trimesic acid metal–organic framework (HCF/Copper-TMA). The characterization results confirmed the successful doping of Fe(CN)63- in the pores and voids of Copper-TMA. Factors affecting the doping, including the concentration of HCF, temperature, and time were optimized. The HCF-modified sensor (CPE/HCF-Copper-TMA) presents extraordinary electrocatalytic activity toward ultra-trace amounts of bisphenol A. Electrochemical tests verify that incorporation of HCF ions in the pores and voids of Copper-TMA MOF increases the sensitivity of the sensor toward ultra-trace amounts of BPA. The proposed sensor shows high sensitivity (0.923 µAµM−1) and wide linear range (linear responses in the concentration range of 0.05 – 60 μM with a detection limit of 20 nM (S/N = 3). This sensor presents advantages, including outstanding sensitivity, excellent selectivity, low detection limit, good reproducibility, and excellent stability. Moreover, the recovery values (between 96% and 106%) show that the modified sensor is a good candidate for detection of BPA residues in drinking water, milk, and orange juice samples.

Qualitative Determination of Bisphenol A and Phthalate Residues in Drinking Water Alternatives in Kayseri Province of Türkiye

In this study, it was aimed to qualitatively determine Bisphenol A and dibutyl phthalate residues in carboy, pet bottled and tap waters used as drinking water in Kayseri-Türkiye. Being used as an additive in the production of many products and plastics frequently used in daily life, BPA and phthalates are associated with a variety of health issues and environmental problems. Within the scope of this study, a total of 20 drinking water samples (9 pet, 7 carboy and 4 tap water) were analyzed in terms of dibutyl phthalat (DBP), BPA and BPA derivatives (Bisphenol S and Bisphenol F). Among the pet bottled water samples; 8 (88.88%) were found to be contaminated with BPA, 5 (55.55%) with DBP and 7 (77.77%) with BPA derivatives, while 1(14.28%) of the carboy water samples were found contaminated with BPA and 7(100%) with DBP. Among the tap water samples, 2 (50%) were contaminated with BPA and 4 (100%) with DBP. No BPA derivatives were found in carboy and tap water samples while pet bottled waters were found posi- tive for all three contaminants. On the other hand, all carboy and tap waters were found contaminated with phthalates. The findings of this study reveal that the most variety of contamination for these chemicals is determined in pet bottled waters. This study highlighted the situation of BPA and phthalate residues in drinking water sources. Measures should be taken to prevent the contamination of all types of drinking water and to systematically examine the BPA and phthalate-related safety of drinking waters. Further investigation is needed to determine and quantify the occurrence of the target compounds.

Highly sensitive electrochemical BPA sensor based on titanium nitride-reduced graphene oxide composite and core-shell molecular imprinting particles.

A sensitive electrochemical sensor was proposed via combining molecular imprinting technique with the graphene material-doped titanium nitride. The novel graphene with 3-dimensional structure displayed more binding sites and better electrochemical properties. Moreover, this study focused on coating pyrrole with electrical conductivity on the surface of silica as a monomer, and BPA as the template. The interaction made specific detection possible, between monomer and template. With a series of characterizations and electrochemical measurements, CPE (carbon paste electrode)-contained TiN-rGO composite was proved to have conductivity improved. Also, the modified polymer performed well selectivity which reflected in that it was almost impervious to distractions. Under optimized conditions, a linear dependence was observed from 0.5 to 100nmolL-1 with a detection limit of 0.19nmolL-1. The sensor explicated outstanding repeatability via repetitive experiment with the RSD of 0.02%, while the results of stability experiment reached the RSD of 1.90%. Eventually, it was used to analyze BPA residues in 3 kinds of daily supplies. The results indicated the potential of the sensor in environmental detection prospectively.

Preliminary evaluation of plasticizer and BPA in Tunisian cosmetics and investigation of hazards on human skin cells

ABSTRACTIn this study, 18 plasticizer (phthalates, adipates, sebacates, and others) and BPA residues in some cosmetic samples collected from Tunisian market are evaluated by micro-matrix solid-phase dispersion combined with GC-MS. In parallel, the impact of these molecules and the cosmetics in the human epithelial cell lines is investigated. The cytotoxic activity of cosmetic extracts is evaluated in vitro against B16 and Hep-2 human skin cell lines using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay.This study shows that the tested cosmetic products could constitute a hazard to the consumer health and wellness and that strict safety analysis on cosmetic products needs to be carried out before they are marketed.

Plasticizers and BPA Residues in Tunisian and Italian Culinary Herbs and Spices.

Plasticizers and BPA in Tunisian and Italian spices were determined by GC/MS. Tunisian spices seem to contain more residues than Italian samples. Intake of these contaminants by spices is not a dangerous risk to the consumers. These pollutants could result from environmental pollution or agricultural practices.

2D Porous Aromatic Framework as a Novel Solid-Phase Extraction Adsorbent for the Determination of Trace BPA in Milk

A rapid and effective solid-phase extraction high-performance liquid chromatography fluorescence detection (SPE-HPLC–FLD) method, using a novel porous aromatic framework (PAF-6) as solid-phase extraction sorbent, was established to enrich and determine bisphenol (BPA) in milk and its packing samples. Parameters influencing the extraction efficiency, such as volume of the sample solutions, pH of the sample, and the eluent volume, were examined. The limits of detection and quantitation were 0.1 and 0.33 ng mL−1, respectively. The recovery of the method was desirable at 81–91% and the relative standard deviation was less than 2.35%. Besides, the PAF-6-based cartridges exhibited superior reusability for milk sample analysis. In addition, theoretical computations were performed to further understand the molecular interaction mechanism between the PAF-6 and the BPA. The results showed that PAF-6 had an excellent adsorption capability for BPA based on hydrogen bonding and the inclusion interactions of host–guest. The proposed method is sensitive, simple, and cost-saving, and provides a detection platform for the monitoring of BPA residues in real milk samples.

Photoaffinity Cross-Linking of the Corticotropin-Releasing Factor Receptor Type 1 with Photoreactive Urocortin Analogues

Interaction of natural peptide ligands with class 2 GPCRs, which are targets of biologically important hormones such as glucagon, secretin, and corticotropin-releasing factor (CRF), occurs with a common orientation, in that the ligand C-terminus binds to the extracellular receptor N-terminus, whereas the ligand N-terminus binds to the receptor juxtamembrane domain. N-Terminal truncation, by eight amino acids in the case of CRF, leads to antagonists, suggesting those residues constitute the receptor activating sequence. Here, we identified by photoaffinity cross-linking using p-benzoyl-l-phenylalanine (Bpa) analogues of urocortin (Ucn) the most affine CRF receptor agonist, interaction domains of CRF(1) receptor with Bpa residues at exclusive positions. Specific cleavage patterns of the corresponding ligand-receptor complexes, obtained using several cleavage methods in combination with SDS-PAGE for fragment size determination, showed that a Bpa group located N-terminally or in position 12 binds at the second and such in position 17 or 22 at the first extracellular receptor loop. Our results indicate that the very N-terminal ligand residues (1-11), which are responsible for receptor activation, are oriented to the juxtamembrane domain by interaction of amino acid residues 12, 17, and 22. Our findings contradict a recently proposed interaction model derived from ligand interaction with a soluble receptor N-terminus, indicating that conclusions drawn from such a reduced system may be of limited value to understand the interaction with the full-length receptor.

Biotransformations of bisphenol A in a mammalian model: answers and new questions raised by low-dose metabolic fate studies in pregnant CD1 mice.

We investigated the metabolic fate of a low dose (25 micro g/kg) of bisphenol A [2,2-bis(4-hydroxy-phenyl)propane] (BPA) injected subcutaneously in CD1 pregnant mice using a tritium-labeled molecule. Analytic methods were developed to allow a radio-chromatographic profiling of BPA residues in excreta and tissues, as well as in mothers' reproductive tracts and fetuses, that contained more than 4% of the administered radioactivity. BPA was extensively metabolized by CD1 mice. Identified metabolite structures included the glucuronic acid conjugate of BPA, several double conjugates, and conjugated methoxylated compounds, demonstrating the formation of potentially reactive intermediates. Fetal radioactivity was associated with unchanged BPA, BPA glucuronide, and a disaccharide conjugate. The latter structure, as well as that of a dehydrated glucuronide conjugate of BPA (a major metabolite isolated from the digestive tract), showed that BPA metabolic routes were far more complex than previously thought. The estrogenicity of the metabolites that were identified but not tested for hormonal activity cannot be ruled out; however, in general, conjugated BPA metabolites have significantly lower potency than that of the parent compound. Thus, these data suggest the parental compound is responsible for the estrogenic effects observed in fetuses exposed to BPA during gestation in this mammalian model.

A peptide agonist acts by occupation of a monomeric G protein-coupled receptor: dual sites of covalent attachment to domains near TM1 and TM7 of the same molecule make biologically significant domain-swapped dimerization unlikely.

Membrane receptor dimerization is a well-established event for initiation of signaling at growth factor receptors and has been postulated to exist for G protein-coupled receptors, based on correction of nonfunctional truncated, mutant, or chimeric constructs by coexpression of appropriate normal complementary receptor domains. In this work, we have directly explored the molecular composition of the minimal functional unit of an agonist ligand and the wild-type G protein-coupled cholecystokinin (CCK) receptor, using photoaffinity labeling with a CCK analogue probe incorporating dual photolabile benzoylphenylalanine (Bpa) residues as sites of covalent attachment. This probe, 125I-D-Tyr-Gly-[(Nle28, 31, Bpa29,33)CCK-26-33], was shown to represent a full agonist and to specifically label the CCK receptor. Like probes incorporating individual photolabile residues in these positions,1,2 the two Bpa residues in the dual photoprobe covalently labeled receptor domains in the amino-terminal tail outside TM1 and in the third extracellular loop outside TM7. Absence of demonstrable receptor dimerization after the establishment of dual sites of covalent attachment supports the presence of these two domains within a single receptor molecule. Demonstration of the covalent adduct of a single probe molecule with the two cyanogen bromide fragments of the CCK receptor representing the expected domains further supports this interpretation. Thus, while domain-swapped dimerization of G protein-coupled receptors may be possible as a mechanism of rescue for nonfunctional molecules, it is not necessary for ligand binding and initiation of signaling at a wild-type receptor in this superfamily. The functional unit for CCK action is normally a ligand-receptor monomer.