Highly sensitive determination of tetrabromobisphenol A and bisphenol A in environmental water samples by solid-phase extraction and liquid chromatography-tandem mass spectrometry

Review of the environmental occurrence, analytical techniques, degradation and toxicity of TBBPA and its derivatives

BFRs (brominated flame retardants) are a class of compounds that are added to or applied to polymeric materials to avoid or reduce the spread of fire. Tetrabromobisphenol A (TBBPA) is one of the known BFR used many in industries today. Due to its wide application as an additive flame retardant in commodities, TBBPA has become a common indoor contaminant. Recent researches have raised concerns about the possible hazardous effect of exposure to TBBPA and its derivatives in humans and wildlife. This review gives a thorough assessment of the literature on TBBPA and its derivatives, as well as environmental levels and human exposure. Several analytical techniques/methods have been developed for sensitive and accurate analysis of TBBPA and its derivatives in different compartments. These chemicals have been detected in practically every environmental compartment globally, making them a ubiquitous pollutant. TBBPA may be subject to adsorption, biological degradation or photolysis, photolysis after being released into the environment. Treatment of TBBPA-containing waste, as well as manufacturing and usage regulations, can limit the release of these chemicals to the environment and the health hazards associated with its exposure. Several methods have been successfully employed for the treatment of TBBPA including but not limited to adsorption, ozonation, oxidation and anaerobic degradation. Previous studies have shown that TBBPA and its derivative cause a lot of toxic effects. Diet and dust ingestion and have been identified as the main routes of TBBPA exposure in the general population, according to human exposure studies. Toddlers are more vulnerable than adults to be exposed to indoor dust through inadvertent ingestion. Furthermore, TBBP-A exposure can occur during pregnancy and through breast milk. This review will go a long way in closing up the knowledge gap on the silent and over ignored deadly effects of TBBPA and its derivatives and their attendant consequences.

Metal-organic framework-101 grafted with amino groups as solid-phase extraction adsorbent coupled with liquid chromatography for the determination of phenoxycarboxylic acids in environmental samples

Metal-Organic Framework (MOF) MIL-101 and three amino-modified MIL-101s were synthesized and used as adsorbents for solid-phase extraction of trace-level polar phenoxycarboxylic acids (PCAs) from environmental water samples for quantification by liquid chromatography. The four MOFs were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, N₂ adsorption-desorption isotherm, pore structure analysis and powder X-ray diffraction analysis. Parameters which play important roles in the process of solid phase extraction were optimized. MIL-101-ethylenediamine (ED) was chosen as the optimum adsorbent for the extraction of PCAs due to electron donation of alkyl groups in aliphatic amino groups and the smaller steric hindrance. The extraction efficiency using MIL-101-ED compacted column was compared with three commercial columns and the influence of humic acid (HA) on extraction was investigated. The merits of newly-built SPE-LC method based on MIL-101-ED are as follows: (a) low limits of detection (0.052-0.160 ng mL^-1), (b) wide linear ranges (0.5-1000 ng mL^-1), (c) good repeatabilities (1.33-3.35%) and reproducibilities (2.51-3.49%) and (d) excludability of HA. This method has been applied to the determination of PCAs in environmental water samples successfully.

A Zr(IV)-based porphyrinic metal-organic framework as a solid-phase sorbent for extraction of sulfonamides prior to their quantitation by LC-MS

A porphyrinic metal-organic framework (PCN-224) was fabricated and used as an adsorbent for solid-phase extraction of ultratrace levels of polar sulfonamide antibiotics from food and drinking waters. The PCN-224 was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and powder X-ray diffraction analyses. Parameters affecting the extraction efficiency were optimized. The sulfonamides were quantified by liquid chromatography-tandem mass spectrometry. Figures of merit include (a) low limits of detection (0.07-0.47 ng·L^-1), (b) wide linear ranges (0.5-2000 ng·L^-1), and (c) good repeatabilities (2.8%-6.7%) and reproducibilities (1.7%-5.1%). The method was successfully applied to the determination of sulfonamides in food and drinking water samples. Graphical abstract A Zr(IV)-based porphyrinic metal-organic framework (PCN-224) was synthesized from a Zr₆ cluster and the H₂TCPP ligand. It was used for solid-phase extraction of sulfonamides from food and drinking water samples coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination.

Environmental occurrence, analysis and human exposure to the flame retardant tetrabromobisphenol-A (TBBP-A)-A review

TBBP-A is a high production volume chemical applied widely as a flame retardant in printed circuit boards. Recent studies have raised concern over potential harmful implications of TBBP-A exposure in human and wildlife, leading to its classification under group 2A "Probably carcinogenic to humans" by the International Agency for Research on Cancer. This article provides a comprehensive review of the available literature on TBBP-A analysis, environmental levels and human exposure. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been identified as the method of choice for robust, accurate and sensitive analysis of TBBP-A in different matrices. TBBP-A has been detected in almost all environmental compartments all over the world, rendering it a ubiquitous contaminant. Human exposure studies revealed dust ingestion and diet as the major pathways of TBBP-A exposure in the general population. Toddlers are likely to be more exposed than adults via accidental indoor dust ingestion. Moreover, exposure to TBBP-A may occur prenatally and via breast milk. There are no current restrictions on the production of TBBP-A in the EU or worldwide. However, more research is required to characterise human exposure to TBBP-A in and around production facilities, as well as in e-waste recycling regions.

Preparation and use of maize tassels' activated carbon for the adsorption of phenolic compounds in environmental waste water samples

The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC) × GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solid-phase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84-98.49%, 80.75-97.11%, and 78.27-97.08% for BPA, o-NTP, and PCP, respectively). The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.

Simultaneous extraction of bisphenol A and tetrabromobisphenol A from milk by microwave-assisted ionic liquid microextraction

A rapid, simple and efficient method was first applied to the simultaneous analysis of BPA and TBBPA in commercial milk.

Biomonitoring method for bisphenol A in human urine by ultra-high-performance liquid chromatography-tandem mass spectrometry

An ultra-high-performance liquid chromatography-tandem mass spectrometry method for the measurement of total bisphenol A in human urine was developed and validated. The method utilized liquid/liquid extraction with 1-chlorobutane and a human urine aliquot size of 800μL. Chromatography was performed on an Acquity UPLC(®) system with a Kinetex(®) Phenyl-Hexyl column. Mass spectrometric analysis was with negative electrospray ionization on a Quattro Premier XE™. The surrogate matrix method was used for the preparation of calibration standards in synthetic urine due to the presence of BPA in control human urine. The validated calibration range was 0.75-20ng/mL with a limit of detection of 0.1ng/mL. The internal standard was d16-bisphenol A. Method validation utilized quality control samples at three concentrations in both synthetic urine and human urine. Bisphenol A mono-glucuronide was fortified in synthetic urine in each analytical run to monitor the enzymatic conversion of the glucuronide conjugate to BPA by β-glucuronidase. Validated method parameters included linearity, accuracy, precision, integrity of dilution, selectivity, re-injection reproducibility, recovery/matrix effect, solution stability, and matrix stability in human urine. Acceptance criteria for analytical standards and QCs were ±20% of nominal concentration. Matrix stability in human urine was validated after 24h at ambient temperature, after three freeze/thaw cycles, and after frozen storage at -20°C and -80°C for up to 218 days. The method has been applied to the analysis of over 1750 human urine samples from a biomonitoring study. The median and mean urine BPA concentrations were 2.71ng/mL and 4.75ng/mL, respectively.

Biotin-streptavidin enzyme-linked immunosorbent assay for detecting Tetrabromobisphenol A in electronic waste

Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant. A sensitive and selective indirect competitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (BA-ELISA) was developed for detecting TBBPA. The optimal hapten of TBBPA was 2-(2,6-dibromo-4-(2-(3,5-dibromo-4-hydroxyphenly)propan-2-yl)) acetic acid. Several physiochemical factors that influence assay performance, such as optimal coupling concentration of immunogen and antibody, organic solvent, ionic strength, and pH, were studied and optimized. The limit of detection (IC10) was 0.027 ng/mL and the median inhibitory concentration (IC50) was 0.58 ng/mL. The BA-ELISA was highly selective, with low cross-reactivity with TBBPA analogs. Finally, the assay was used to detect TBBPA in electronic waste samples. The results are consistent with those using liquid chromatography, which proves that the proposed immunoassay is accurate and receptive. This BA-ELISA method is suitable for the rapid and sensitive screening of TBBPA in environmental monitoring.

Molecularly imprinted electrochemical sensor based on a reduced graphene modified carbon electrode for tetrabromobisphenol A detection

A simple strategy for the indirect detection of 3,3',5,5'-tetrabromobisphenol A (TBBPA) was developed with a surface imprinted sensor based on an electrochemical reduced graphene modified carbon electrode. The preparation procedure of imprinted electrode and the response mechanism of the imprinted electrode toward TBBPA are discussed in detail. The electrochemical characteristics of the imprinted sensor were investigated using cyclic voltammetry and their morphologies were characterized using scanning electron microscopy. The indirect detection for TBBPA was successfully implemented by monitoring the peak current of Fe(CN)6(3-/4-)-TBBPA complex. The response currents of the imprinted sensor exhibited a linear relationship toward the TBBPA concentration range from 0.5 to 4.5 nM with a detection limit of 0.23 nM (S/N = 3). The fabricated electrochemical imprinted sensor was successfully applied to the detection of TBBPA in rain and lake water samples using the standard addition method. With the advantages of high sensitivity and simple operation, the determination methodology is a promising candidate for TBBPA detection in real water samples.

Quantitation of tetrabromobisphenol-A from dust sampled on consumer electronics by dispersed liquid-liquid microextraction

Tetrabromobisphenol-A (TBBPA) is a brominated flame retardant used worldwide. Despite its widespread use, there are few data concerning environmental concentrations of TBBPA. Thus, the objective of this work was to optimize an ultrasound-assisted dispersed liquid-liquid microextraction (DLLME) method to analyze swabbed surfaces of consumer electronics to determine TBBPA concentrations. Upon sample preparation with DLLME, TBBPA was derivatized with acetic anhydride and then analyzed by gas chromatography-mass spectrometry (GC/MS). Using a (13)C12-TBBPA internal standard to improve precision and quantitation, a recovery study was performed. At concentrations of 250-1000 ng/mL, recoveries were 104-106%. Sample preparation with solid phase extraction had comparable recoveries, although overall, improved analyte recovery and precision were achieved with DLLME. In a small survey study, TBBPA concentrations in dust collected from 100 cm(2) areas on electronic surfaces (monitor, microwave, refrigerator, and TV) were determined to range from less than the LOQ to 523 ng/mL.

Application of ozone for the removal of bisphenol A from water and wastewater--a review

The extensive use of Bisphenol A (BPA) in the plastics industry has led to increasing reports of its presence in the aquatic environment, with concentrations of ng L(-1) to μg L(-1). Various advanced oxidation processes, including ozonation, have been shown to effectively degrade BPA. This paper reviews the current advancements in using ozone to remove BPA from water and wastewater. Most of the published work on the oxidation of BPA by ozone has focused on the efficiency of BPA removal in terms of the disappearance of BPA, and the effect of various operational parameters such as ozone feed rate, contact time and pH; some information is available on the estrogenic activity of the treated water. Due to increasing operational reliability and cost effectiveness, there is great potential for industrial scale application of ozone for the treatment of BPA. However, there is a significant lack of information on the formation of oxidation by-products and their toxicities, particularly in more complex matrices such as wastewater, and further investigation is needed for a better understanding of the environmental fate of BPA.

Online in-tube microextractor coupled with UV-Vis spectrophotometer for bisphenol A detection

A simple and high extraction efficiency online in-tube microextractor (ITME) was developed for bisphenol A (BPA) detection in water samples. The ITME was fabricated by a stepwise electrodeposition of polyaniline, polyethylene glycol and polydimethylsiloxane composite (CPANI) inside a silico-steel tube. The obtained ITME coupled with UV-Vis detection at 278 nm was investigated. By this method, the extraction and pre-concentration of BPA in water were carried out in a single step. Under optimum conditions, the system provided a linear dynamic range of 0.1 to 100 μM with a limit of detection of 20 nM (S/N ≥3). A single in-tube microextractor had a good stability of more than 60 consecutive injections for 10.0 μM BPA with a relative standard deviation of less than 4%. Moreover, a good tube-to-tube reproducibility and precision were obtained. The system was applied to detect BPA in water samples from six brands of baby bottles and the results showed good agreement with those obtained from the conventional GC-MS method. Acceptable percentage recoveries from the spiked water samples were obtained, ranging from 83-102% for this new method compared with 73-107% for the GC-MS standard method. This new in-tube CPANI microextractor provided an excellent extraction efficiency and a good reproducibility. In addition, it can also be easily applied for the analysis of other polar organic compounds contaminated in water sample.

Quantum dots capped with dummy molecularly imprinted film as luminescent sensor for the determination of tetrabromobisphenol A in water and soils

Molecularly imprinted film with diphenolic acid (DPA) as dummy template molecule has been grafted on the surface of Mn-doped ZnS quantum dots (QDs) to develop a selective and sensitive sensor for rapid determination of tetrabromobisphenol A (TBBPA) in water and soils. The obtained DPA-MIP-QDs sensor has distinguished selectivity and high binding affinity to TBBPA. The fluorescence quenching fractions of the sensor presented a satisfactory linearity with the concentrations of TBBPA in the range of 0.1-100 μM, and its limit of detection can reach 0.015 μM. The sensor has been successfully applied to determine the TBBPA in water and soil samples, and the average recoveries of the TBBPA at various spiking levels ranged from 80.2% to 96.5% with relative standard deviation below 8.0%. The results provided a clue to develop sensors for rapid determination of hazardous materials from complex matrixes.

Measurement of bisphenol A, bisphenol A ß-D-glucuronide, genistein, and genistein 4'-ß-D-glucuronide via SPE and HPLC-MS/MS

Bisphenol A (BPA) is a synthetic industrial reactant used in the production of polycarbonate plastics, and genistein is a natural phytoestrogen abundant in the soybean. Current studies investigating the endocrine-disrupting effects of concomitant exposures to BPA and genistein have warranted the development of an analytical method for the simultaneous measurement of BPA and genistein, as well as their primary metabolites, bisphenol A ß-D-glucuronide (BPA gluc) and genistein 4'-ß-D-glucuronide (genistein gluc), respectively. All four analytes were extracted from rat plasma via solid phase extraction (SPE). Three SPE cartridges and four elution schemes were tested. Plasma extraction using Bond Elut Plexa cartridges with sequential addition of ethyl acetate, methanol, and acetonitrile yielded optimal average recoveries of 98.1 ± 1.8% BPA, 94.9 ± 8.0% genistein, 91.4 ± 6.1% BPA gluc, and 103 ± 6.1% genistein gluc. Identification and quantification of the four analytes were performed by a validated HPLC-MS/MS method using electrospray ionization and selective reaction monitoring. This novel analytical method should be applicable to the measurement of BPA, genistein, BPA gluc, and genistein gluc in urine, cultures, and tissue following in vivo exposures. While reports of the determination of BPA and genistein independently exist, the simultaneous optimized extraction and detection of BPA, genistein, BPA gluc, and genistein gluc have not previously been reported.