Quantification of free and total bisphenol A and bisphenol B in human urine by dispersive liquid-liquid microextraction (DLLME) and heart-cutting multidimensional gas chromatography-mass spectrometry (MD-GC/MS)

A novel method combining dispersive liquid-liquid microextraction (DLLME) and heart-cutting multidimensional gas chromatography coupled to mass spectrometry was developed for the determination of free and total bisphenol A (BPA) and bisphenol B (BPB) in human urine samples. The DLLME procedure combines extraction, derivatization and concentration of the analytes into one step. Several important variables influencing the extraction efficiency and selectivity such as nature and volume of extractive and dispersive solvents as well as the amount of acetylating reagent were investigated. The temperature and time to hydrolyze BPA and BPB conjugates with a β-glucuronidase and sulfatase enzyme preparation were also studied. Under the optimized conditions good efficiency extraction (71-93%) and acceptable total DLLME yields (56-77%) were obtained for both analytes. Matrix-matched calibration curves were linear with correlation coefficients higher than 0.996 in the range level 0.1-5 μg/l, and the relative standard deviations (%RSD) were lower than 20% (n = 6). The limits of detection were 0.03 and 0.05 μg/l for BPA and BPB, respectively. The applicability of the proposed method for determining urinary free and total BPA and BPB was assessed by analyzing the human urine of a group of 20 volunteers. Free BPA was detected in 45% of the sample whereas total BPA was detected in 85% of the samples at concentrations ranging between 0.39 and 4.99 μg/l. BPB was detected in conjugated form in two samples.     

Determination of bisphenol A in human breast milk by HPLC with column-switching and fluorescence detection

A highly sensitive HPLC method was developed for the determination of xenoestrogenic compound, bisphenol A (BPA) in human breast milk samples. After a two-step liquid-liquid extraction, BPA was derivatized with fluorescent labeling reagent, 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl). The excess fluorescent reagent could be removed effectively using a column-switching system. The separation of DIB-BPA from endogenous materials in milk was carried out on two C(18) columns and fluorescence intensity was monitored at 475 nm with the excitation of 350 nm. A good linearity (r = 0.994) was observed of BPA in the concentration range of 0.2-5.0 ng mL(-1) in breast milk, and the detection limit was 0.11 ng mL(-1) at a signal-to-noise ratio of 3. Intra- and inter-day precision (RSD, %) were less than 8.7 and 10.4, respectively. Twenty-three breast milk samples of healthy lactating women were analyzed for the BPA concentration; the mean value was 0.61 +/- 0.20 ng mL(-1), with no correlation to the lipid content of milk samples.     

Measurement of bisphenol A in human serum by gas chromatography/mass spectrometry

The purpose of this study is to establish an easy and accurate method for the determination of bisphenol A (BPA) in the human serum. The samples were applied to the C₁₈ solid phase extraction (SPE) column for clean up of samples. The BPA is conjugated with tetrabutylammonium hydrogen sulfate as the counter ion in alkali solution. The ion paired BPA is moves from the aqueous phase to the organic phase as an ion paired extraction. BPA extracted from human serum were derivatized with pentafluorobenzyl bromide (PFBBr). The derivative was analyzed by gas chromatography (GC)/mass spectrometry (MS) using negative chemical ionization (NCI). The instrumental detection limit of BPA was 5 pg/ml (10 fg). The instrumental response between 0.01 and 100 pg/ml of BPA standards was linear (r²=0.998). The recovery of BPA spiked into human serum was 101.0±4.63 (1 pg/ml) and 100.9±3.75 (10 pg/ml), respectively. The concentration of BPA in the human serum from 20 individuals was 0.54 pg/ml.     

Investigation of diazo‐derivatization of bisphenol A and its applicability for quantitation in food safety inspections using high‐performance liquid chromatography

Bisphenol A (BPA) is a common additive in food packaging materials, and many methods have been discovered to limit BPA for the sake of food safety. This study aims to find a more sensitive quantification method for BPA. It was determined that a diazo derivative of BPA could be obtained when reacted with a stable and inexpensive reagent, p‐methylaniline, exhibiting an increased response in the ultraviolet spectrum than that of nonreacted BPA. Based on this discovery, an accurate method of BPA quantitation was established using a precolumn derivatization HPLC method. The results of this study showed the low limit of detection and the limit of quantitation for BPA were 3.6 and 10.9 pg/mL on‐column, respectively. This method is proven to have much higher sensitivity and a lower limit of detection than direct HPLC determination methods. This method is robust, easily handled, sensitive and cost‐effective for the quantitation of BPA. In addition, the broad application of this method to determine BPA content in plastic bottled drinking water, distilled water, tap water, milk, Sprite and grape juice was demonstrated in this paper.     

Efficient access to bisphenol A metabolites: Synthesis of monocatechol,mono-o-quinone,dicatechol, and di-o-quinone of bisphenol A

2-Iodoxybenzoic acid (IBX) oxidation of bisphenol A (BPA) is described. The selective production of either the mono-o-quinone or the di-o-quinone can be controlled by IBX stoichiometry. Isolated yields of quinone were greater than 80%. Previous synthesis of BPA-di-o-quinone using a large excess of Fremy’s salt produced only trace amounts of product. In addition to o-quinone products, both mono- and dicatechols of BPA can synthesize in high yield and isolated without chromatography. The more stable catechols can be quantitatively converted back to o-quinones using silver oxide oxidation in either acetone or DMF. These one-pot reactions provide access to four different BPA metabolites in high yield and significant scale.     

Synthesis and characterization of polycyclic structures and linear polycarbonate copolymers from a bisphenol A dimer

An o,o′‐methylene‐bridged bisphenol A (BPA) dimer 2 was synthesized by a one‐step reaction between formalin and excess BPA in the presence of a cation exchange resin in a polar aprotic solvent. Novel oligomeric polycyclic structures were synthesized by the reaction of reactive difunctional halides, methyl phosphonic dichloride, phenyl phosphonic dichloride, and dimethyl dichlorosilane with the BPA dimer under high‐dilution conditions. The yields of the polycyclics were quite high. NMR and matrix‐assisted laser desorption ionization–time of flight mass spectrometry (MALDI–TOF MS) were very useful in the characterization of the dimer and its oligomeric polycyclic analogs. These polycyclics can potentially be used as precursors for advanced thermosetting materials. A series of polycarbonate copolymers of BPA were synthesized by solution polycondensation of the methylene bridged dimer of BPA with triphosgene. Alternatively, the co‐polycarbonate containing crosslinkable moieties was synthesized by in‐situ polymerization of BPA and BPA dimer with triphosgene. The copolymers were characterized by GPC. TG/DTA and DSC were used to investigate the thermal properties of the co‐polycarbonates. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 927–935, 1999     

Concentration of bisphenol A in thermal paper

Abstract

Bisphenol A (BPA) is widely used as a color developer in thermal paper. Thermal paper is ubiquitous in daily life due to its use in cash register receipts, so opportunities for human contact abound. For this study, 10 blank cash register receipts were obtained from businesses in suburban Boston. BPA was extracted and analysis of concentration was performed using gas chromatograph/flame ionization detector. In some receipts, BPA was not detected but in others it was as high as 19 mg for a 12-inch long receipt, which is in line with concentrations indicated in patents. This study is intended to highlight the potential for human exposure to BPA as well as the ease with which exposure may be reduced through the use of BPA-free thermal paper.     

土壤悬浮液中双酚A的光降解研究

实验研究了双酚A在土壤表面的吸附特征及在土壤悬浮液中的光降解.研究结果表明,双酚A在土壤表面的吸附为单分子的化学吸附,用Langmuir模型或Freundlich模型拟合时相关性较好.在高压汞灯(λ=300nm)照射下,双酚A在土壤悬浮液中能快速降解,降解速度随酸度的增大而加快.在此体系中双酚A光降解动力学遵循Langmuir-Hinshelwood(H-L)方程,在土壤量不超过10g/L的条件下,降解率随土壤量增加而增加,加入腐殖酸可以促进双酚A的光解,同时增大光照强度有利于双酚A的降解.     

Development and validation of an HPLC method for the determination of endocrine disruptors bisphenol A and benzophenone in thermochromic printing inks

The endocrine disruptors bisphenol A (BPA) and benzophenone (BFN) could be important ingredients in thermochromic printing inks in significant amounts. Due to patent protection and use of the inks, manufacturers are not obliged to state their precise chemical composition. These substances in increasingly used thermochromic printing inks present a hazard for human health and environment in the case of inappropriate application and waste disposal. In this work we enabled identification of the inks that contain these hazardous substances by developing a new method for the analysis of BPA and BFN in thermochromic printing inks. The method is based on the reversed-phase liquid chromatography (LC) with UV detection at 226 and 254?nm. Ultrasound-assisted sample extraction in methanol was proven to be the most suitable and effective among several other solvents. The method was completely validated with satisfactory results. The specificity of the method was proven by the additional LC–tandem mass spectrometry analysis. A representative group of 15 ink samples from various manufacturers, curing and printing modes was analyzed. BPA was found in three samples with mass fractions of about 2% while BFN was found in two samples with mass fractions of 0.34 and 0.66%.     

Development and validation of an LC‐MS/MS method for simultaneous quantitative analysis of free and conjugated bisphenol A in human urine

Bisphenol A (BPA) is an environmental endocrine‐disrupting chemicals that is widely used in common consumer products. There is an increasing concern regarding human exposure to BPA owing to the potential adverse effects associated with its estrogenic activity. For assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and selective analytical method, especially one that can detect low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography–tandem mass spectrometry method for simultaneous quantification of free BPA and BPA β‐d ‐glucuronide (BPA‐gluc) concentrations in human urine with only a single injection. Calibration curves were linear over a concentration range of 1–100 ng/mL for BPA and 10–1000 ng/mL for BPA‐gluc. The levels of the analytes were determined quantitatively with HPLC/ESI‐MS/MS by using negative electrospray ionization in the select ion monitoring mode and a pentaflouraphenyl propyl column. The validated method was applied to the analysis of spot urine specimens collected from randomly selected healthy human subjects. Copyright © 2013 John Wiley & Sons, Ltd.     

基于碳量子点修饰硅胶荧光法测定塑料制品中的双酚A

制备了碳量子点修饰的硅胶SiO2@CDs.在盐酸介质中KBrO3能够氧化碳量子点使其荧光发射峰减弱,而双酚A(BPA)对此氧化猝灭有明显抑制作用,据此建立了荧光法测定痕量双酚A的新方法,线性范围是20~500μg·L-1,检出限3σ为5.2μg·L-1.本文作者将该方法成功用于塑料制品中双酚A的测定,回收率在95%~104%之间.     

Depolymerization of Poly（bisphenol A carbonate） in Subcritical and Supercritical Toluene

The depolymerization of poly(bisphenol A carbonate)(PC) in subcritical and supercritical toluene was studied. The experimental parameters, which influence the depolymerization reaction such as temperature (570-633 K), pressure (4.0-7.0 MPa), reaction time (5-60 min), and toluene to PC weight ratio (3.0-11.0), were investigated, and the reaction products were determined by GC, GC/MS and FT-IR spectrometer. It was found that the main product of the depolymerization reaction was bisphenol A(BPA). BPA accounted for over 55.7% of the depolymerization products at reaction temperature 613 K, pressure 5.0-6.0 MPa, reaction time 15 min and toluene/PC weight ratio of around 7.0.     

Simultaneous identification and quantification of bisphenol A and 12 bisphenol analogues in environmental samples using precolumn derivatization and ultra high performance liquid chromatography with tandem mass spectrometry

A method for the identification and quantification of bisphenol A and 12 bisphenol analogues in river water and sediment samples combining liquid–liquid extraction, precolumn derivatization, and ultra high‐performance liquid chromatography coupled with tandem mass spectrometry was developed and validated. Analytes were extracted from the river water sample using a liquid–liquid extraction method. Dansyl chloride was selected as a derivatization reagent. Derivatization reaction conditions affecting production of the dansyl derivatives were tested and optimized. All the derivatized target compounds were well separated and eluted in 10 min. Dansyl chloride labeled compounds were analyzed using a high‐resolution mass spectrometer with electrospray ionization in the positive mode, and the results were confirmed and quantified in the parallel reaction monitoring mode. The method validation results showed a satisfactory level of sensitivity. Linearity was assessed using matrix‐matched standard calibration, and good correlation coefficients were obtained. The limits of quantification for the analytes ranged from 0.005 to 0.02 ng/mL in river water and from 0.15 to 0.80 ng/g in sediment. Good reproducibility of the method in terms of intra‐ and interday precision was achieved, yielding relative standard deviations of less than 10.1 and 11.6%, respectively. Finally, this method was successfully applied to the analysis of real samples.     

Thermal properties of polycarbonate grade bisphenol A

Thermal properties of 4,4(2,2-propylidene)-diphenol, referred to as bisphenol A, or BPA, are discussed. Parameters of thermal transitions were measured by DSC. The commercial product crystallizes in -form crystals which melt at 157°C (onset) and 161°C (peak) with a heat of fusion 134.37 J g^–1. Supercooled BPA shows a glass transition at about 40°C. Almost identical results were obtained for samples recovered by different methods: flakes, pastilles and prills. Two new polymorphs, the and -forms were identified. The -form melts at 131°C with a heat of fusion of 104.9 J g^–1. The melting point of the -form was measured to be 138°C and its heat of fusion is 118.3 J g^–1. Thermal conductivity of crystalline BPA was measured.Dedicated to Professor Bernhard Wunderlich on the occasion of his 65th birthdayThe author wishes to acknowledge helpful discussions with Dr. C. W. Uzelmeier and Dr. R. L. June during the course of this work. Many thanks go to J. M. Olvera for her help in gathering the experimental data.     

纳米银增强化学发光法测定塑料中的双酚A

研究发现在碱性介质中,纳米银对luminol-KMnO4化学发光体系的发光信号具有强烈的增敏作用,而双酚A对该体系具有明显的抑制作用,据此结合流动注射技术,建立了流动注射化学发光分析法测定塑料中双酚A的方法。该方法测定双酚A的线性范围为8.0×10-11～1.0×10-8g.mL-1(0.9926)和1.0×10-8～8.0×10-8g.mL-1(0.9916),检出限(3σ)为6.5×10-11g.mL-1。对5.0×10-10g.mL-1和5.0×10-8g.mL-1双酚A平行测定11次,其相对标准偏差为1.4%和1.0%。对反应机理进行了讨论。该方法简单、快速、灵敏度高,用于塑料制品中双酚A的测定,回收率为97.0%～105.0%。     

Highly ordered molecularly imprinted mesoporous silica for selective removal of bisphenol A from wastewater

Selective removal of bisphenol A from wastewater is quite challenging primarily because of its low concentration and matrix complexity. To this end, according to the molecular structure of bisphenol A, we designed a functional monomer for the preparation of molecularly imprinted mesoporous silica using click chemistry reaction. The resultant bisphenol A imprinted mesoporous silica was characterized by transmission electron microscopy, small angle X‐ray diffraction, and N₂ adsorption–desorption experiments. The results indicated that the bisphenol A imprinted mesoporous silica possessed a highly ordered periodic hexagonal mesostructure with the Brunauer–Emmett–Teller surface area of 944.28 m²/g. The bisphenol A imprinted mesoporous silica showed fast adsorption kinetics and the saturated adsorption capacity reached up to 88.6 mg/g at pH 6.5, and with relative selectivity factors ranged from 1.06 to 3.20. The adsorption efficiency of the bisphenol A imprinted mesoporous silica was above 97.96% after five extraction/elution cycles. The bisphenol A imprinted mesoporous silica was further applied to the selective removal of bisphenol A from real wastewater samples and showed great promise in practical applications.     

Comparison of three cyclodextrins to optimize bisphenol A extraction from source water: Computational,spectroscopic, and analytical studies

Computationally and spectroscopically assisted analytical comparative investigation into the extraction of bisphenol A using three cyclodextrins, that is, α, β, and γ respectively, were performed. A simple, self-tailored μ-solid-phase extraction podium was used to extract bisphenol A from water samples, and high-performance liquid chromatography-ultraviolet was used for the qualitative and quantitative analysis of bisphenol A. Density functional theory first principle calculations, attenuated total reflectance Fourier-transform infrared spectroscopy and Fourier-transform Raman spectroscopy data supports the analytical selection of β-cyclodextrin as the adsorbent for bisphenol A extraction. Analytical optimization of various parameters including sample volume, sample pH, eluting solvent and its volume was performed to discover the most proper conditions for maximum extraction. Under the optimized conditions, a limit of detection value of 0.70 ng/ml and a limit of quantification value of 2.31 ng/ml was achieved with β-cyclodextrin, with recovery (%) values over 98.40–102.50 in real source water samples. Overall, well assisted by comprehensive computational and spectroscopic studies, a novel, simple, sensitive and economic analytical method was developed for the extraction of bisphenol A from source water using cyclodextrin.     

Synthesis and properties of a bisphenol A based phthalonitrile resin

A multiple aromatic ether linked phthalonitrile was synthesized and characterized. The oligomeric phthalonitrile monomer was prepared from the reaction of an excess amount of bisphenol A with 4,4′‐difluorobenzophenone in the presence of K₂CO₃ as the base in an N,N‐dimethylformamide/toluene solvent mixture, followed by end capping with 4‐nitrophthalonitrile in a two‐step, one‐pot reaction. The monomer properties were compared to those of the known resin 2,2‐bis[4‐(3,4‐dicyanophenoxy)phenyl]propane after being cured in the presence of bis[4‐(4‐aminophenoxy)phenyl]sulfone. Rheometric measurements and thermogravimetric analysis showed that the oligomeric phthalonitrile resin maintained good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long‐term oxidative stability. The ether‐linked phthalonitrile resin absorbed less than 2.5% water by weight after exposure to an aqueous environment for extended periods. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4136–4143, 2005     

Migration of pseudoestrogen bisphenol A from various types of paper with thermochromic prints to artificial sweat solutions

Abstract

Thermochromic inks, materials that change color at a certain temperature, are increasingly used on papers and other materials in the areas of design, commercials, and security printing. Pseudo-estrogen bisphenol A (BPA) may be one of their main compounds present in mass fractions of up to several percent. In this work, the mass fractions of BPA in thermochromic prints on seven types of paper were determined. Migration of BPA from the surface of the thermochromic print to artificial sweat solutions was investigated as well. Total amount of BPA in papers with thermochromic prints was determined by an HPLC-UV method with ultrasonic-assisted extraction in methanol developed and validated in this work. Total amount of BPA, which ranged from 0.126 to 0.778?mg/g, was compared with the amounts extracted under the same conditions in two artificial human sweat solutions, which differed in chemical composition, ionic strength, and pH-value. Mass fractions of BPA extracted with artificial sweat solutions were from 0.047 to 0.175?mg/g with respect to the mass of the paper. On average, the mass fraction of BPA was four times less when extracted with artificial sweat solutions than the maximal amount extracted with methanol. The amounts of extracted BPA raise a concern of health risk through dermal exposure to BPA from thermochromic prints on paper.     

分子印迹聚合物为涂层的吸附萃取搅拌棒在环境水样双酚A含量测定中的应用

以双酚A(BPA)为单体,利用整体材料“原位”聚合技术制备以分子印迹聚合物为涂层的吸附萃取搅拌棒(MIP-SBSE),然后与高效液相色谱(HPLC)-二极管阵列检测器联用,探讨其对环境水样BPA的选择萃取性能。优化萃取过程中吸附和解吸时间、解吸液种类以及基底pH值和离子强度对目标化合物的选择吸附性能。在最佳条件下,MIP-SBSE可对模板分子进行有效的选择吸附,线性范围为1.0～200 μg/L,检出限(S/N=3)和定量限(S/N=10)分别为0.28μg/L和0.94 μg/L。在实际水样分析中,具有良好的加标回收率,其值为96.0%～108.7%。研究结果表明,所建立的方法具有简便、灵敏和环境友好等特点。