Simultaneous determination of phenolic xenoestrogens by solid-phase extraction and high-performance liquid chromatography with fluorescence detection

Determination of bisphenols in beeswax based on sugaring out-assisted liquid-liquid extraction: Method development and application in survey, recycling and degradation studies

The methodology of sugaring out-assisted liquid-liquid extraction (SULLE) coupled with high-performance liquid chromatography-fluorescence detection was devised for quantifying bisphenol A (BPA) and bisphenol B (BPB) in beeswax. The effectiveness of SULLE was methodically explored and proved superior to the salting out-assisted liquid-liquid extraction approach for beeswax sample preparation. The analytical performance underwent comprehensive validation, revealing detection limits of 10 μg/kg for BPA and 20 μg/kg for BPB. The method developed was employed to analyse commercial beeswax (n = 15), beeswax foundation (n = 15) and wild-build comb wax (n = 26) samples. The analysis revealed BPA presence in four commercial beeswax samples and three beeswax foundation samples, with the highest detected residue content being 88 ± 7 μg/kg. For BPB, two beeswax foundation samples were positive, with concentrations below the limits of quantification and 85 ± 4 μg/kg, respectively. No bisphenols were detected in wild-build comb wax. Furthermore, the bisphenol removal efficacy of two recycling methods-boiling in water and methanol extraction-was assessed. The findings indicated that after four recycling cycles using water boiling, 9.6% of BPA and 29.2% of BPB remained in the beeswax. Whereas methanol extraction resulted in approximately 7% residual after one recycling process. A long-term study over 210 days revealed the slow degradation of bisphenols in comb beeswax. This degradation fitted well with a first-order model, indicating half-lives (DT50) of 139 days for BPA and 151 days for BPB, respectively. This research provides the first report on bisphenol contamination in beeswax. The low removal rate during the recycling process and the gradual degradation in beeswax underscore the significance of bisphenol contamination and migration in bee hives along with their potential risk to pollinators warranting concern. Furthermore, the developed SULLE method shows promise in preparing beeswax samples to analyse other analytes.

Presence of Bisphenol A and Parabens in a Neonatal Intensive Care Unit: An Exploratory Study of Potential Sources of Exposure

BACKGROUND

Newborns in neonatal intensive care units (NICUs) are in contact with a variety of medical products whose production might include synthetic chemicals with hormonal activity.

OBJECTIVES

Our aim was to assess the content of bisphenol A (BPA) and parabens (PBs) and the hormone-like activities of a subset of medical products commonly used in NICUs in prolonged intimate contact with NICU newborns.

METHODS

Fifty-two NICU items were analyzed, determining the concentrations of BPA and PBs [methyl- (MeP), ethyl- (EtP), propyl- (PrP), and butylparaben (BuP)] and using the E-Screen and PALM-luciferase assays to measure the in vitro (anti-)estrogenic and (anti-)androgenic activity, respectively, of the extracts. Items found to have elevated BPA/PB content or hormone-like activities were further extracted using leaching methodologies.

RESULTS

BPA was found in three-fifths and PBs in four-fifths of tested NICU items, and ∼25% and ∼10% of extracts evidenced estrogenic and anti-androgenic activity, respectively. The highest BPA content was found in the three-way stopcock (>7.000 ng/g), followed by patterned transparent film dressing, gastro-duodenal feeding tubes, sterile gloves, single-lumen umbilical catheters, and intravenous (IV) infusion extension sets (concentrations ranged from 100 to 700 ng/g BPA). A total PB concentration (∑PBs) >100 ng/g was observed in several items, including light therapy protection glasses, patterned transparent film dressing, winged IV catheters, IV infusion extension sets, and textile tape. The highest estrogenic activity [>450 pM estradiol equivalent (E2eq)] was found in small dummy nipples, three-way stopcocks, and patterned transparent film dressing and the highest anti-androgenic activity [>5 mM procymidone equivalent units per gram (Proceq/g)] in small dummy nipples and three-way stopcocks.

DISCUSSION

According to these findings, neonates might be exposed to multiple sources of BPA and PBs in NICUs via inhalation, dermal, oral, and IV/parenteral routes. There is a need to address the future health implications for these extremely vulnerable patients and to adopt precautionary preventive measures as a matter of urgency. https://doi.org/10.1289/EHP5564.

Synthesis, Characterization, and Application of Poly(4,4'-Cyclohexylidene Bisphenol Oxalate) for Solid-Phase Extraction of DNA

The present study has synthesized poly(4,4'-cyclohexylidene bisphenol oxalate) by the condensation of oxalyl chloride with 4,4'-cyclohexylidene bisphenol, where its efficacy was tested for the solid-phase extraction of DNA. The synthesized polymer in the form of a white powder was characterized by FTIR, TGA-DTG, SEM, and BET analysis. The study utilized solid-phase application of the resulting polymer to extract DNA. The analysis of results provided the information that the extraction efficiency is a strong dependent of polymer amount and binding buffer type. Among the three types of buffers tested, the GuHCl buffer produced the most satisfactory results in terms of yield and efficiency of extraction. Moreover, the absorbance ratio of A260/A280 in all of the samples varied from 1.682 to 1.491, thereby confirming the capability of poly(4,4'-cyclohexylidene bisphenol oxalate) to elute pure DNA. The results demonstrated an increased DNA binding capacity with respect to increased percentage of the polymer. The study has concluded that poly(bisphenol Z oxalate) can be applied as one of the potential candidates for the high efficiency extraction of DNA by means of a simple, cost-effective, and environmentally friendly approach compared to the other traditional solid-phase methods.

Quantitative screening for endocrine-disrupting bisphenol A in consumer and household products using NanoAptamer assay

The NanoAptamer assay is a bisphenol A (BPA) quantification method that uses magnetic beads, quantum dot nanoparticles, and a BPA-specific aptamer. In this study, screening of various consumer and household products for BPA was demonstrated utilizing the NanoAptamer assay. First, the experimental conditions suitable for BPA detection using the NanoAptamer assay were examined in terms of incubation time, temperature, and buffer composition. The range of BPA quantification via the NanoAptamer assay was determined to be 0.005-1000 ng/mL of BPA. The selectivity was confirmed by detecting BPA in an analog mixture containing bisphenol S and bisphenol F. Finally, a leaching experiment using 20 consumer and household products classified into 4 categories was performed to demonstrate the capability of the NanoAptamer assay for BPA detection. The experiment was validated by high-performance liquid chromatography analysis (correlation coefficient, r = 0.99).

Chemometrics-assisted cyclodextrin-enhanced excitation-emission fluorescence spectroscopy for the simultaneous green determination of bisphenol A and nonylphenol in plastics

The aim of this work was to quantify two relevant priority chemicals, bisphenol A (BPA) and 4-nonylphenol (NP), coupling the sensitivity of fluorescence in organized media and the selectivity of multivariate calibration, measuring excitation-emission fluorescence matrices in an aqueous methyl-β-cyclodextrin solution. The studied priority pollutants are two of the most frequently found xenoestrogens in the environment, and are therefore of public health concern.The data were successfully processed by applying unfolded partial least-squares coupled to residual bilinearization (U-PLS/RBL), which provided the required selectivity for overcoming the severe spectral overlapping among the analyte spectra and also those for the interferents present in real samples. A rigorous International Union of Pure and Applied Chemistry (IUPAC)-consistent approach was applied for the calculation of the limits of detection. Values in the ranges of 1-2 and 4-14 ng mL(-1) were obtained in validation samples for BPA and NP, respectively. On the other hand, low relative prediction errors between 3% and 8% were achieved. The proposed method was successfully applied to the determination of BPA and NP in different plastics. In positive samples, after an easy treatment with a small volume of ethanol at 35°C, concentrations were found to range from 26 to 199 ng g(-1) for BPA, and from 95 to 30,000 ng g(-1) for NP.

Release of bisphenols from can coatings into canned beer in China market

BACKGROUND

The aim of this research was to understand the migration of bisphenols from can coatings into foods in the Chinese market.

RESULTS

The migration of bisphenols was studied in commercial cans from the Chinese market filled with four types of food simulant (FS), which were heated at 121 °C for 30 min and stored at 40 °C for 30 days. Only bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE) were found in the can coatings, and SimC (10% (v/v) ethanol/water) was the most suitable FS for their release. The levels of these bisphenols in 24 kinds of canned beer from Chinese markets were also investigated. The average concentrations of BPA and BADGE were 2.85 ± 0.79 and 0.38 ± 0.19 µg · L⁻¹ respectively, which were both lower than the EU limits, and their respective daily intakes were estimated at 0.015 and 0.0020 µg · kg⁻¹ body weight · day⁻¹. Besides, increasing storage temperature and time accelerated the release of bisphenols into FSs.

CONCLUSION

The present results provide some guidance to reduce the migration of bisphenols during the transport and storage of canned foods.

Determination of bisphenol a and bisphenol B residues in canned peeled tomatoes by reversed-phase liquid chromatography

Bisphenol A (BPA) and bisphenol B (BPB) concentrations were determined in peeled canned tomatoes of different brands bought in Italian supermarkets. Tomato samples analyzed were packaged in cans coated with either epoxyphenolic lacquer or low BADGE enamel. A solid phase extraction (SPE) was performed on C-18 Strata E cartridge followed by a step on Florisil cartridge. Detection and quantitation were performed by a reversed phase high-performance liquid chromatography (RP-HPLC) method with both UV and fluorescence detection (FD). On the total of 42 tested tomato samples, BPA was detected in 22 samples (52.4%), while BPB was detected in 9 samples (21.4%). BPA and BPB were simultaneously present in 8 of the analyzed samples. The levels of BPA found in this study are much lower than the European Union migration limits of 3 mg/kg food and reasonably unable to produce a daily intake exceeding the limit of 0.05 mg/kg body weight, established by European Food Safety Authority.

Direct enrichment and high performance liquid chromatography analysis of ultra-trace Bisphenol A in water samples with narrowly dispersible Bisphenol A imprinted polymeric microspheres column

Direct injection, enrichment and high performance liquid chromatography (HPLC) analysis of ultra-trace Bisphenol A (BPA) in water samples using one narrowly dispersible BPA imprinted polymeric microspheres (MIPM) column in one analysis process was developed. One BPA imprinted MIPM that had the best globular morphology and imprinted efficiency was used as HPLC stationary phase and applied to direct analysis of ultra-trace BPA in water. The optimum direct analysis conditions were: conditioning the MIPM column with water for 10min, injecting 40mL water sample directly, eluting with 70% methanol for 13min and then 100% methanol for 7min. Under the optimum conditions, the MIPM column can simultaneously extract, enrich, separate and determine ultra-trace BPA in one analysis process with UV detector by injection of large volume water samples (40mL). The calibration graph was linear with R(2)>0.998 in the ranges from 0.1-100nmol/L BPA standard solution. The intra- and inter-day RSD are less than 9.5 and 9.6%, respectively. The limit of quantification was 0.1nmol/L. RSD for spiked tap and lake water was less than 8.9% and the recoveries were 96-101.8%. The enrichment factor for BPA was 10,000 as 40mL water sample was directly injected and analyzed.

Liquid phase microextraction with in situ derivatization for measurement of bisphenol A in river water sample by gas chromatography-mass spectrometry

A new method that involves liquid phase microextraction (LPME) with in situ derivatization and gas chromatography-mass spectrometry (GC-MS) is described for the determination of trace amounts of bisphenol A (BPA) in river water samples. The LPME conditions, such as the type of extraction solvent and the extraction time, are investigated. Then, the extract is directly injected into GC-MS. The detection limit and the quantification limit of BPA in river water sample are 2 and 10pgml(-1) (ppt), respectively. The calibration curve for BPA is linear with a correlation coefficient of >0.999 in the range of 10-10,000pgml(-1). The average recoveries of BPA in river water samples spiked with 100 and 1000pgml(-1) BPA are 104.1 (RSD: 8.9%) and 98.3 (RSD: 3.2%), respectively, with correction using the added surrogate standard, bisphenol A-(13)C(12). This simple, accurate, sensitive and selective analytical method may be applicable to the determination of trace amounts of BPA in liquid samples.

High-performance liquid chromatographic analysis of bisphenol A and 4-nonylphenol in serum, liver and testis tissues after oral administration to rats and its application to toxicokinetic study

A sensitive and simple method based on solid-phase extraction (SPE) and HPLC with fluorescence detection for the determination of bisphenol A (BPA) and 4-nonylphenol (4-NP) in rat serum, liver and testis tissues has been developed. The chromatographic conditions consisted of a C18 column and mobile phase composition of acetonitrile and water with flow rate of 1.0 ml/min. The fluorescence detection was performed at excitation and emission wavelengths of 227 nm and 313 nm, respectively. Under these conditions, BPA and 4-NP were well separated and showed good linearities in the ranges of 0.01-50.0 microg/ml for BPA and 0.15-150.0 microg/ml for 4-NP with correlation coefficients greater than 0.999. The detection limits of serum and tissue samples were 2.8 ng/ml and 1.4 ng/g for BPA and 5.6 ng/ml and 2.8 ng/g for 4-NP at a signal-to-noise ratio (S/N) of 3. The intra-assay and the inter-assay precisions were better than 11.4%. Recoveries of BPA and 4-NP were 78.6-95.0% and 80.2-93.4%, respectively. The proposed method was applied to a toxicokinetic study of BPA and 4-NP including individual and combined oral administration to rats. The results showed that 4-NP remarkably altered the toxicokinetic parameters of BPA in testis, while parameters of BPA were not obviously altered in serum and liver under the experimental conditions investigated. On the other hand, there was no significant difference in the toxicokinetics of 4-NP when administered with BPA.

Determination of Bisphenol-A in Water by Semi-Micro Column High-Performance Liquid Chromatography Using 2-Methoxy-4-(2-phthalimidinyl)-phenylsulfonyl Chloride as a Fluorescent Labeling Reagent

A highly sensitive method for the determination of bisphenol-A in water with semi-micro column high-performance liquid chromatography using 2-methoxy-4-(2-phthalimidinyl)phenylsulfonyl chloride as a fluorescent labeling reagent has been developed. The labeling reaction was carried out at 70 degrees C for 20 min in borate buffer (pH 9.5). The derivative eluted at 11.6 min on a reversed-phase column with methanol-water (78:22, v/v) at a flow-rate of 0.2 ml/min. The fluorescence was monitored at 308 nm for excitation and 410 nm for emission. The detection limit (S/N = 3) was 10 fmol per injection. The labeling yield was about 95%.

Trace analysis of phenolic xenoestrogens in water samples by stir bar sorptive extraction with in situ derivatization and thermal desorption–gas chromatography–mass spectrometry

A method for the simultaneous measurement of trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butyl-phenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) analysis. The conditions for derivatization with acetic acid anhydride were investigated. A polydimethylsiloxane (PDMS)-coated stir bar and derivatization reagents were added to 10 ml of water sample and stirring was commenced for 10-180 min at room temperature (25 degrees C) in a headspace vial. Then, the extract was analyzed by TD-GC-MS. The optimum time for SBSE with in situ derivatization was 90 min. The detection limits of 2,4-DCP, BP, OP, NP, PCP and BPA were 2, 1, 0.5, 5, 2 and 2 pg ml(-1), respectively. The method showed good linearity over the concentration ranges of 10, 5, 2, 20, 10 and 10-1000 pg ml(-1) for 2,4-DCP, BP, OP, NP, PCP and BPA, respectively, and the correlation coefficients were higher than 0.99. The average recoveries of those compounds in river water samples were equal to or higher than 93.9% (R.S.D. <7.2%) with correction using the added surrogate standards. This simple, accurate, sensitive and selective method can be used in the determination of trace amounts of phenolic xenoestrogens in river water samples.

Determination of bisphenol A in river water and body fluid samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography–mass spectrometry

A new method, based on stir bar sorptive extraction (SBSE) with in situ derivatization and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) is described for the determination of trace amounts of bisphenol A (BPA) in river water, urine, plasma, and saliva samples. The derivatization conditions with acetic acid anhydride and the SBSE conditions such as sample volumes and extraction time are investigated. Then, the stir bar is subjected to TD followed by GC-MS. The detection limits of BPA in river water, urine, plasma, and saliva samples are 1-5, 20, 100, and 20pgml(-1) (ppt), respectively. Calibration for BPA was shown to be linear with a correlation coefficient of >0.99. The average recoveries of BPA in all samples are higher than 95% (R.S.D. < 10%) with correction using an added surrogate standard, 13C12-bisphenol A. This simple, accurate, sensitive, and selective analytical method may be applicable to the determination of trace amounts of BPA in liquid samples.

Simultaneous determination of endocrine disrupting phenolic compounds and steroids in water by solid-phase extraction–gas chromatography–mass spectrometry

A solid-phase extraction (SPE)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of endocrine disrupting chemicals (EDCs) from water samples is described in detail. Important and contrasting EDCs including estrone, 17beta-estradiol, 17beta-ethynylestradiol, 16beta-hydroxyestrone, 4-nonylphenol, bisphenol A and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with bis (trimethylsilyl) trifluoroacetamide was used for the extraction recoveries of target compounds from water samples. A number of parameters that may affect the recovery of EDCs, such as the type of SPE cartridges, eluents, as well as water properties including pH value, and concentration of salts and humic substances were investigated. It is shown that the Oasis cartridges produced the best recoveries of target EDCs while ethyl acetate was efficient in eluting EDCs from SPE cartridges. The recovery of some EDCs was enhanced by the addition of salt, but reduced by the increase in pH value and humic acid concentration. The optimised method was further verified by performing spiking experiments in natural river water and seawater matrices, with good recovery and reproducibility for all the selected compounds. The established method was successfully applied to environmental water samples from East and West Sussex, UK, for the determination of the target EDCs.

Lophine derivatives as versatile analytical tools

Lophine (2,4,5-triphenylimidazole) derivatives as versatile analytical tools in biomedical sciences are described. Chemiluminescence (CL) and fluorescence (FL) properties of the lophine derivatives are first demonstrated including the CL reaction mechanism, effects of substituents on CL yields, FL spectral behaviors, etc. Next, analytical applications to the determination of metal ions such as cobalt (II) and chromium (VI) are discussed. Finally, the application studies of lophine derivatives as CL and FL reagents for the determination of organic substances in biological materials are presented. Among the derivatives, 2-(4-hydrazinocarbonylphenyl)-4,5-diphenylimidazole (HCPI) and 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) are studied, with their excellent properties as labeling reagents for fatty acids and amines and/or phenols, respectively, in high-performance liquid chromatography. The utility of boronic acid derivatives as CL enhancers is also discussed in this review.