Improved sample treatment for the determination of bisphenol A and its chlorinated derivatives in sewage sludge samples by pressurized liquid extraction and liquid chromatography-tandem mass spectrometry

Synthesis and characterization of pH-responsive deep eutectic solvent followed by HPLC for trace determination of bisphenol A in water samples

A microextraction based on pH-responsive deep eutectic solvent combined with high-performance liquid chromatography was developed for the separation, preconcentration, and determination of bisphenol A in water samples. Five deep eutectic solvents were prepared using thymol (hydrogen bond acceptor) and 6-, 8-, 9-, 10-, and 12-carbon carboxylic acids (hydrogen bond donor), and were used as extraction solvent. Herein, by alkalinizing the environment, phase transition takes place, and by adding acid, phase separation and extraction of analytes occur simultaneously. Some important parameters on the extraction such as deep eutectic solvent type, molar ratio of deep eutectic solvent components, deep eutectic solvent volume, potassium hydroxide concentration, hydrochloric acid volume, extraction time, and salt addition were optimized. Under the optimum conditions, intra- and interday precisions of the method based on seven replicate measurements of 10 μg L-1 of bisphenol A in water samples were 2.2% and 4.3%, respectively. The analytical performance of the method showed linearity over the concentration of 0.05-50 μg L-1 with the detection limit of 0.02 μg L-1 . The accuracy of the method was confirmed by spiking different concentrations of bisphenol A in real water samples and obtaining relative recoveries in the range of 92.5%-105.2%.

A novel UPLC-ESI-MS assay for fifteen portal estrogens and metabolites detection and application in hepatic fibrosis

Estrogens and their metabolites (EMs) are involved in chronic liver disease and gut microbiota regulates estrogen metabolism, whereas the role of enterogenous EMs in liver disease is still elusive. Because of the extremely low level of EMs in portal serum and the EMs contain multiple pairs of isomers, an accurate determination of portal serum EMs is urgently needed. This study established a quantitative detection method for portal serum EMs and applied to non-alcoholic fatty liver disease (NAFLD) related hepatic fibrosis mice model. The serum was derived with a novel derivatization reagent 4-acetyl aminobenzene sulfonyl chloride, and a UPLC-ESI-MS system was used for quantification of 15 EMs in 120 min. Compared with normal group, the concentrations of E1, E2 in model group were significantly decreased by 4-8 times, all the C2 and C4 substitution products (2-OHE1, 2-OHE2, 2-MeOE1, 4-OHE1, 4-MeOE1, 4-OHE2, 4-MeOE2, 2-MeOE2) were significantly decreased by 2-22 times. However, the C16 and C17 substitution products (E3, 16-epiE3, 17-epiE3, 16-ketoE2) levels were increased by 3-5 times (P < 0.01). This study elucidated the changes of enterogenous EMs which entered the liver via portal vein in NAFLD - related hepatic fibrosis and provided methodological platform for other related studies on estrogen metabolism.

Techniques for the detection and quantification of emerging contaminants

In recent years, the diverse industrial practices and human inputs widely disseminated emerging contaminants (ECs) throughout environmental matrices, which is of great concern. Even at low concentrations, ECs pose major ecological problems and threaten human health and the environment’s biota. Consequently, people’s interest and concerns on the widespread dissemination of environmentally connected ECs of great concern as developed due to their scientific understanding, technical innovation, and socioeconomic awareness. Increased detection of contaminants may occur from climatic, socioeconomic, and demographic changes and the growing sensitivity of analytical techniques. Hence, this article reviews the determination of ECs in ecological specimens, from aquatic setup (river water, marine water, and wastewater), sludge, soil, sediment, and air. Sample collection and the quality measures are summarized. The preparation of samples, including extraction and cleanup and the subsequent instrumental analysis of ECs, are all covered. Traditional and recent extraction and cleanup applications to analyze ECs in samples are reviewed here in this paper. The detection and quantification of ECs using gas chromatography (GC) and liquid chromatography (LC) linked with various detectors, particularly mass spectrometry (MS), is also summarized and explored, as are other possible techniques. This study aims to give readers a more excellent knowledge of how new and improved approaches are being developed and serve as a resource for researchers looking for the best method for detecting ECs in their studies.

Determination of Very Low Concentration of Bisphenol A in Toys and Baby Pacifiers Using Dispersive Liquid-Liquid Microextraction by In Situ Ionic Liquid Formation and High-Performance Liquid Chromatography

Bisphenol A (BPA) is a chemical compound used in the manufacturing of plastics and resins whose presence in the body in low concentrations can cause serious health problems. Due to this, there is a growing interest in the scientific community to develop analytical methods that allow quantifying trace concentrations of BPA in different types of samples. The determination of this compound in toys made of plastics that can be manipulated by children leads to an extra concern, because it is possible for BPA to enter the body by introducing these toys into the mouth. This work presents a novel procedure to the quickly and easily quantification of trace levels of BPA in samples of toys and pacifiers according to the current demanding regulations. The determination of very low levels of BPA was carried out by ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) followed by high-performance liquid chromatography (HPLC). The formation in situ of the ionic liquid (IL) 1-octyl-3-methylimidazolium bis((trifluoromethane)sulfonyl)imide ([C8MIm] [NTf2]), was achieved by mixing 1-octyl-3-methylimidazolium chloride ([C8MIm]Cl) and lithium bis(trifluoromethanesulfonyl)imide ([NTf2]Li) aqueous solutions, reaching an instant dispersion whose cloud of microdrops allows the total extraction of BPA in the IL from aqueous solutions. After centrifugation, BPA concentration in the sedimented phase was determined by HPLC. The optimal experimental conditions for the microextraction and determination of BPA in the IL were studied. The total extraction was achieved at pH 4, heating the sample at 30 °C for 5 min, using 100 µL of IL precursor volume, and spinning after the formation of dispersion at 3000 rpm for 10 min. The enrichment factor (EF) and detection limit (LOD) reached with the procedure were 299 and 0.19 µg L-1, respectively. The relative standard deviation for ten replications at the 0.5 µg L-1 level was 5.2%. Recovery studies showed a mean value for BPA recovery percentage in the samples of 99%. Additionally, a hybrid model was applied to characterize the extraction kinetics. This simple, low cost and fast method simplifies traditional microextraction techniques, representing an outstanding alternative.

Quantitative Analysis of Heavy Metals and Organic Compounds in Soil from Deir Kanoun Ras El Ain Dump, Lebanon

Recently, there has been a worldwide concern regarding soil contamination by heavy metals and organic compounds, especially in the developing countries including Lebanon that has suffered from solid waste mismanagement for decades. Deir Kanoun Ras El Ain is a village in southern Lebanon that possesses one of the country's worst dumps, and its leachates influx into a running canal that irrigates surrounding agricultural lands. The aim of this study was to determine the levels of some toxic heavy metals and organic compounds in different soil samples collected from the dump and along the canal during winter and summer seasons. Six research sites (four from the dump and two along the canal) were selected, and the soil samples for analysis were collected from a depth of around 10 cm. Heavy metals (lead, cadmium, arsenic, and mercury) and organic compounds (phthalates, bisphenol A, and polyaromatic hydrocarbons) content were determined using atomic absorption and high pressure liquid chromatography, respectively. The conducted research confirmed high levels of contamination in the collected soil samples by both heavy metals and organic compounds. The present study provided evidence that different sampling sites accumulated heavy metals at concentrations that exceeded the average maximum permissible levels for sewage sludge and agricultural land. These findings suggest the need for mitigation measures by the Lebanese authorities and new waste management programs to resolve the problems associated with uncontrolled dumping of solid wastes in Lebanon.

Selective pressurized liquid extraction of plant secondary metabolites: Convallaria majalis L. as a case

A fast and efficient selective pressurized liquid extraction (sPLE) method was developed to extract secondary metabolites from complex plant matrix. Convallaria majalis L., a plant producing toxic steroids, was used as proof-of-concept. The method was optimized in the aspects of preheating, dispersant, extraction temperature and solvent, and the use of C18 as in-cell cleanup sorbent. Eight authentic natural steroids with diverse sugar moieties and hydrophobicities were selected as reference analytes and spiked to 0.1 g dried leaves. The extraction performance was evaluated based on the analytes' stability, recovery, matrix effect in the electrospray interface and the level of co-extractives. With the optimal method, the extraction was finished in 10 min. A colorless extract was obtained with recoveries ranging from 63% to 107% and absolute matrix effects ranging from 3% to 27%. The optimized method was validated by extracting 0.1 g, 0.2 g and 0.4 g spiked plant samples; method accuracy and precision were assessed by recoveries and relative standard deviations of the combined extraction-analysis workflow. The method was also tested on soil samples and indicated its suitability for measuring secondary metabolites in multiple environmental matrices. To our knowledge, this is the first time sPLE has been reported to extract plant secondary metabolites from a complex plant matrix, with satisfactory recoveries and low matrix effects. This is also the first time (s)PLE has been reported to extract plant secondary metabolites from soil. We envision the method be coupled with liquid chromatography-electrospray ionization-high resolution mass spectrometry in a standard metabolomics workflow to facilitate plant metabolomics studies.

Determination of endocrine disruptive phenolic compounds by gas chromatography mass spectrometry after multivariate optimization of switchable liquid-liquid microextraction and assessment of green profile

This study presents an accurate method for the determination of alkyl phenols and bisphenol A at trace levels using gas chromatography mass spectrometry after preconcentration with switchable liquid-liquid microextraction. In order to achieve high extraction output, the environmentally friendly switchable liquid-liquid microextraction method was optimized by varying parameters such as amount of switchable solvent, sodium hydroxide concentration/amount and the mixing period in a Box-Behnken experimental design. Under optimum extraction conditions, the limits of detection calculated for the analytes were between 0.13 and 0.54 ng/mL. The analytes showed good linearity over broad calibration ranges, and low percent relative standard deviations established good precision. Spiked recovery studies were performed on municipal wastewater and tap water to determine the method's suitability and accuracy, and the results (87-106%) obtained were satisfactory. Bisphenol A was detected (4.0-14 ng/mL) in four plastic samples investigated under high temperature conditions.

Spatial distribution of parabens, triclocarban, triclosan, bisphenols, and tetrabromobisphenol A and its alternatives in municipal sewage sludges in China

Parabens, triclocarban (TCC), triclosan (TCS), bisphenols (BPs), and tetrabromobisphenol A and its alternatives (TBBPAs) are used in a broad range of daily consumer products and industrial productions. Concerns have been raised over exposure of humans to these chemicals, because of their adverse health effects. However, information on the spatial distribution of parabens, TCC, TCS, BPs and TBBPAs in sludge from waste water treatment plants (WWTPs) in China is still limited. In this study, 19 endocrine disrupting chemicals, including six parabens, two antimicrobials (TCC and TCS), eight BPs and three TBBPAs, were determined in sludges from 46 WWTPs across China. Concentrations of target chemicals were found in a decreased order as: ∑(TCC+TCS) (mean: 3930, range: 1340-11,100ng/g dw)>∑₈BPs (201, 23.1-1240ng/g dw)>∑₆parabens (67.9, 10.4-272ng/g dw)>∑₃TBBPAs (18.4, 1.36-195ng/g dw). Methyl paraben (MeP), TCC, bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) were the major compounds found in sludge, accounting for 89.0%, 57.7%, 85.8% and 93.3% of ∑₆parabens, ∑(TCC+TCS), ∑₈BPs and ∑₃TBBPAs, respectively. Elevated concentrations of BPs and TBBPAs were found in sludges from the Northeast China and Central South China (p<0.05), respectively, whereas there were no significant spatial difference in concentrations of parabens or antimicrobials among different geographical regions (p>0.05). Calculation of mass loading showed that sludge from East China (1340kg/yr) and South Central China (1060kg/yr) released relatively more such chemicals. This nationwide study provided baseline concentrations of these chemicals in sludges and estimated their environmental release through sludge in China.

Simultaneously determination of bisphenol A and its alternatives in sediment by ultrasound-assisted and solid phase extractions followed by derivatization using GC-MS

Bisphenol analogues are a group of chemicals which are being widely applied in industrial and household products owing to regulations on bisphenol A (BPA) in many countries. In this study, an analytical method, including extraction from complex environmental matrices, clean-up using solid phase extraction (SPE) and following-up derivatization prior to gas chromatography coupled with mass spectrometry (GC-MS), was developed to analyze seven commonly used bisphenols in sediment. Five kinds of extraction solvents, four kinds of SPE cartridges, and four kinds of SPE eluting solvents were individually tested for their performances; and the conditions for derivatizing were also optimized. Finally, C₁₈ cartridge was determined as the SPE cartridge and methanol was selected as extracting and eluting solvent. Acetic anhydride (AA) was used as derivatizing agent and reaction took 20 min at room temperature. The method was used successfully to measure the seven bisphenol compounds in sediment samples from Taihu Lake, China. BPA, bisphenol F and bisphenol S were detected in all sediment samples, with concentrations in the range of 3.94-33.2; 0.503-3.28 and 0.323-27.3 ng g^-1 dw. Other compounds were detected at low frequencies or not detected. We provided a convenient, reliable, and sensitive method to analyze bisphenol compounds in complex environmental samples.

Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A

The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (ClxBPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA exposures have led to the gradual market entry of BPA structural analogs, such as bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), etc. A suite of exposure sources to ClxBPA and BPA analogs in the domestic environment is anticipated to drive the nature and range of halogenated BPA derivatives that can form when residual BPA comes in contact with disinfectant in tap water and/or consumer products. The primary objective of this review was to survey all available studies reporting biomonitoring protocols of ClxBPA and structural BPA analogs (BPS, BPF, BPB, etc.) in human matrices. Focus was paid on describing the analytical methodologies practiced for the analysis of ClxBPA and BPA analogs using hyphenated chromatography and mass spectrometry techniques, because current methodologies for human matrices are complex. During the last decade, an increasing number of ecotoxicological, cell-culture and animal-based and human studies dealing with ClxBPA exposure sources and routes of exposure, metabolism and toxicity have been published. Up to date findings indicated the association of ClxBPA with metabolic conditions, such as obesity, lipid accumulation, and type 2 diabetes mellitus, particularly in in-vitro and in-vivo studies. We critically discuss the limitations, research needs and future opportunities linked with the inclusion of ClxBPA and BPA analogs into exposure assessment protocols of relevant epidemiological studies.

A study on temporal trends and estimates of fate of Bisphenol A in agricultural soils after sewage sludge amendment

Temporal concentration trends of BPA in soils were investigated following sewage sludge application to pasture (study 1: short term sludge application; study 2: long term multiple applications over 13 years). The background levels of BPA in control soils were similar, ranging between 0.67-10.57 ng g(-1) (mean: 3.02 ng g(-1)) and 0.51-6.58 ng g(-1) (mean: 3.22 ng g(-1)) for studies 1 and 2, respectively. Concentrations in both treated and control plots increased over the earlier sampling times of the study to a maximum and then decreased over later sampling times, suggesting other sources of BPA to both the treated and control soils over the study period. In study 1 there was a significant treatment effect of sludge application in the autumn (p=0.002) although no significant difference was observed between treatment and control soils in the spring. In study 2 treated soils contained considerably higher BPA concentrations than controls ranging between 12.89-167.9 ng g(-1) (mean: 63.15 ng g(-1)). This and earlier studies indicate the long-term accumulation of multiple contaminants by multiple sewage sludge applications over a prolonged period although the effects of the presence of such contaminant mixtures have not yet been elucidated. Fugacity modelling was undertaken to estimate partitioning of Bisphenol A (soil plus sewage: pore water: soil air partitioning) and potential uptake into a range of food crops. While Bisphenol A sorbs strongly to the sewage-amended soil, 4% by mass was predicted to enter soil pore water resulting in significant uptake by crops particularly leafy vegetables (3.12-75.5 ng g(-1)), but also for root crops (1.28-31.0 ng g(-1)) with much lower uptake into cereal grains (0.62-15.0 ng g(-1)). This work forms part of a larger programme of research aimed at assessing the risks associated with the long-term application of sewage sludge to agricultural soils.

Emission of bisphenol analogues including bisphenol A and bisphenol F from wastewater treatment plants in Korea

Due to the regulation on bisphenol A (BPA) in several industrialized countries, the demand for other bisphenol analogues (BPs) as substitutes for BPA is growing. Eight BPs were determined in sludge from 40 representative wastewater treatment plants (WWTPs) in Korea. Total concentrations of BPs (ΣBP) in sludge ranged from <LOQ to 25700 ng g(-1). The highest concentrations of ΣBP were found in sludge collected from WWTPs that received discharges from the paper and textile industries. The profiles of BPs were dependent on the proportions of industrial wastewater treated at each of the WWTPs. The sludge from industrial WWTPs contained elevated proportions of BPA, whereas sludge from domestic WWTPs was dominated by bisphenol F (BPF), suggesting use of BPF in certain industrial products in Korea. No significant correlations were found between BPs and the WWTP characteristics. The average per-capita emissions of BPs ranged from 0.04 (BPP) to 886 g capita(-1) d (BPA) through WWTP discharges. The emission fluxes of ΣBP through industrial WWTPs were 2-3 orders of magnitudes higher than those calculated for domestic WWTPs, indicating that industrial discharges are the major source of BPs into the Korean environment. This is the first nationwide survey of BPs in sludge from Korean WWTPs.

Cd-doped ZnO quantum dots-based immunoassay for the quantitative determination of bisphenol A

Bisphenol A (BPA) is a ubiquitous environmental contaminant in food products and aquatic ecosystems. Its endocrine and developmental toxicity presents a serious concern to human health and an effective high-throughput method for its detection is desirable. In this paper, water-soluble quantum dots (QDs) have been conjugated covalently with BPA antibodies and the conjugate has been utilized in a competitive fluorescence-linked immunoassay (FLISA). Cd-doped ZnO QDs were functionalized with poly(amidoamine) (PAMAM) dendrimers, as evidenced by ultraviolet absorption spectrum and fluorescence emission spectra analyses, and this led to their successful transfer into aqueous solution. Biological mass spectrometry demonstrated that the bisphenol A antibodies were successfully coupled to the water-soluble QDs, and the structures of these conjugates kept intact. The FLISA method allowed for BPA determination in a linear working range of 20.8-330.3 ng mL(-1) with the limit of detection (LOD) of 13.1 ng mL(-1). The recoveries of BPA from water samples were from 85.92% to 109.62%. In conclusion, a rapid and sensitive FLISA was developed by utilizing novel QD coupling method and validated for use in aqueous samples.