Migration of di‐(2‐ethylhexyl)adipate (DEHA) and acetyl tributyl citrate (ATBC) plasticizers from PVC film into the food stimulant of isooctane

Chemical migration from food packing is influenced by several factors such as nature of chemicals, complexity of food, temperature, packing material used and properties of the migrating substances. Chemical compounds that are incorporated within polymeric packaging materials may interact with food components during processing or storage and migrate into the food by jeopardizing the food safety. This migration is higher if food remains in contact with packing material for extended time. Polyvinyl chloride (PVC) film such as di‐(2‐ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC) are still widely used as a food packing material due to its flexibility, transparency and low water permeability. The present study covers the main migration phenomena of both plasticizers (di‐(2‐ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC)) from PVC‐film into isooctane food stimulant using a direct gas chromatographic method. An exposure period of 48 h at 30 °C and 4 °C was used. The obtained results showed DEHA levels ranging of 7.2 mg/dm² while, no ATBC migration from PVC‐film was observed. Results are discussed in relation to EU legislation proposed upper limit for DEHA specific migration (18 mg/L or 3 mg/dm²) and overall migration limit (OM) of 10 mg/dm².     

加速溶剂萃取-GC-MS/MS法测定食品接触材料中双酚A、双酚F及其衍生物的残留量

建立了加速溶剂萃取-气相相色谱-串联质谱法测定食品接触材料(婴儿奶瓶)中双酚A、双酚F及其衍生物残留量的分析方法。样品用二氯甲烷作提取剂,用加速溶剂萃取仪进行了提取,经乙酸酐衍生化,用气相色谱-串联质谱仪进行了定性、定量分析。结果表明:BPA,BPF,BADGE,BFDG 4种化合物的回收率范围在78.9%～101.1%之间,相对标准偏差小于10%,线性关系良好,方法的检出限分别为0.2,0.1,5,5 ng/g,该方法简便、快速、灵敏度高、重复性好。     

Aminolated and Thiolated PEG‐Covered Gold Nanoparticles with High Stability and Antiaggregation for Lateral Flow Detection of Bisphenol A

The few lateral flow assays (LFAs) established for detecting the endocrine disrupting chemical bisphenol A (BPA) have employed citrate‐stabilized gold nanoparticles (GNPs), which have inevitable limitations and instability issues. To address these limitations, a more stable and more sensitive biosensor is developed by designing strategies for modifying the surfaces of GNPs with polyethylene glycol and then testing their effectiveness and sensitivity toward BPA in an LFA. Without the application of any enhancement strategy, this modified BPA LFA can achieve a naked‐eye limit of detection (LOD) of 0.8 ng mL^?1, which is 12.5 times better than the LOD of regular BPA LFAs, and a quantitative LOD of 0.472 ng mL^?1. This modified LFA has the potential to be applied to the detection of various antigens.     

Energy transfer in and fluorescence studies of the Eu-Tb doped BPA-phen system

To enhance the red emission efficiency of Eu³⁺ complexes, [Eu/Tb_x(BPA)₃phen] (BPA?=?bisphenol A, phen?=?1,10-phenanthroline) is designed and synthesized. The complexes are characterized fully and their luminescence properties are evaluated. Co-fluorescence is detected in the Eu/Tb_x(BPA)₃phen complexes, and the existence of Tb³⁺ enhances the luminescence intensity of the central Eu³⁺ because of the intramolecular energy transfer from the ⁵D₄ level of Tb³⁺ to the ⁵D₀ level of Eu³⁺. The luminescence intensity of europium ions at 615?nm is the highest for Eu/Tb₁(BPA)₃phen. To improve the thermal stabilities and mechanical properties of pure complexes, Eu/Tb₁(BPA)₃phen/PAN (PAN?=?polyacrylonitrile) is used to fabricate fibres by electrospinning. Compared with Eu/Tb₁(BPA)₃phen (τ?=?1.1087?ms), the fibres have a longer fluorescence lifetime of 1.533?ms. The fibres also retain a high quantum yield of 47.16%. Thus, the flexible luminescent fibres have potential applications in many fields.     

食品接触材料中双酚类物质迁移检测方法研究

选用去离子水、3%乙酸溶液、10%乙醇溶液和精制橄榄油作为4种食品模拟物,开展了食品接触材料中双酚A,双酚A二甘氨酸醚、双酚F二甘氨酸醚及其衍生物等9种双酚类物质迁移检测方法研究。目标分析物采用反相液相色谱柱分离,荧光检测器进行检测。水基食品模拟物(去离子水、3%乙酸溶液、10%乙醇溶液)中的目标分析物可直接进样,精制橄榄油中的目标分析物依次通过正己烷和甲醇乙腈混合液(体积比1∶1)萃取后进样。结果表明:目标分析物含量在0.008～4mg/L范围内,线性度在0.993以上,相对标准偏差小于15%,方法检测限在0.0011～0.0052mg/L之间。     

Enhanced TiO2 photocatalytic degradation of bisphenol E by beta-cyclodextrin in suspended solutions

Enhancement of beta-cyclodextrin (beta-CD) on TiO(2) photocatalytic degradation of bisphenol E (BPE, bis(4-hydroxyphenyl)ethane) was investigated under a 250 W metal halide lamp (lambda> or =365 nm) in this work. In the system of photocatalytic degradation of BPE, the photodegradation rate of BPE in aqueous solutions containing beta-CD and TiO(2) was obviously faster than that in aqueous solutions containing only TiO(2). After 40 min of irradiation, beta-CD could increase the photodegradation efficiency by about 26% for 10 mg l(-1) BPE in the UV-vis/TiO(2) system and the photodegradation of 2.5-20.0 mg l(-1) BPE in aqueous solutions was found to follow pseudo-first-order law and the adsorption constant and the reaction rate constant of BPE in the system containing beta-CD and TiO(2) are obviously higher than those in the system containing only TiO(2), the influence factors on photodegradation of BPE were studied and described in details, such as beta-CD concentration, pH, BPE initial concentration and gas medium. The formation of CO(2) as a result of mineralization of BPE was observed during the photodegradation process. After 120 min of irradiation, the mineralization efficiency of BPE reached 61% in the presence of beta-CD, whereas mineralization efficiency was only 23% in the absence of beta-CD. The enhancement of photodegradation of BPE could be dependent on the enhancement of adsorption of BPE on TiO(2) surface and moderate inclusion-depth of BPE in the beta-CD cavity.     

Voltammetric detection of bisphenol a by a chitosan-graphene composite modified carbon ionic liquid electrode

In this paper 1-ethyl-3-methylimidazolium tetrafluoroborate based carbon ionic liquid electrode (CILE) was fabricated and further modified with chitosan (CTS) and graphene (GR) composite film. The fabricated CTS-GR/CILE was further used for the investigation on the electrochemical behavior of bisphenol A (BPA) by cyclic voltammetry and differential pulse voltammetry. A well-defined anodic peak appeared at 0.436 V in 0.1 mol/L pH 8.0 Britton-Robinson buffer solution, which was attributed to the electrooxidation of BPA on the modified electrode. The electrochemical parameters of BPA on the modified electrode were calculated with the results of the charge transfer coefficient (α) as 0.662 and the apparent heterogeneous electron transfer rate constant (k_s) as 1.36 s^− 1. Under the optimal conditions, a linear relationship between the oxidation peak current of BPA and its concentration can be obtained in the range from 0.1 μmol/L to 800.0 μmol/L with the limit of detection as 2.64 × 10^− 8 mol/L (3σ). The CTS-GR/CILE was applied to the detection of BPA content in plastic products with satisfactory results.     

Box–Behnken design directed optimization for sensitivity assessment of anti-platelet drugs

Optimization of electrospray ionization (ESI) parameters is routinely carried out by one factor at a time (OFAT) or auto-tune software (ATS). Design of experiments (DOE) approach has been reported to be an excellent alternative to OFAT or ATS. Box–Behnken Design (BBD) was successfully used to optimize ESI parameters like nebulizing gas flow rate, desolvation line temperature, heat block temperature, and drying gas flow rate for [M?+?H]⁺ intensity of Clopidogrel bisulfate (CLP) and Ticlopidine (TLP). BBD model was found to be significant with p?<?.0001 for both CLP and TLP. The predicted and optimized (OL) ESI parameters were used for chromatographic analysis and were compared against three levels of ESI parameters, i.e. low level (LL), medium level (ML), and high level (HL). The OL ESI parameters were subjected to chromatographic analysis and its mean peak area was significantly higher than mean peak area for LL, ML, and HL ESI in case of CLP and TLP (p?<?.001). However, no significant difference was observed between the mean peak area for ML and OL of TLP. Thus, BBD can be considered with 29 trials to optimize four mass spectrometric parameters. The liquid chromatographic parameters percentage of methanol, percentage of formic acid and flow rate were also optimized using BBD. However, the optimized method did not significantly influence the peak response over the non-optimized method.     

食品罐内涂膜中有害化学物质的迁移与检测

食品罐内涂膜中有害化学物质主要有双酚A、双酚A二缩水甘油醚、双酚F、双酚F二缩水甘油醚、酚醛清漆甘油醚及其衍生物等,国际上对这些有害化学物质的使用做出了相关限定。常用的食品罐检测前处理方法有液-液萃取法、固相萃取法以及固相微萃取法等,食品罐内涂膜中有害化学物质的检测方法主要有高效液相色谱法、气相色谱-质谱法和酶联免疫法。针对食品罐内涂膜有害物质迁移的研究还存在有害物质毒性机理不健全和检测方法不完善等问题,寻找一种精确、简便且可同时检测多种有害物质的方法,并加强对有害化学物质迁移模型的建立是该领域的研究方向。     

Nonfullerene Tandem Organic Solar Cells with High Performance of 14.11%

Fabricating solar cells with tandem structure is an efficient way to broaden the photon response range without further increasing the thermalization loss in the system. In this work, a tandem organic solar cell (TOSC) based on highly efficient nonfullerene acceptors (NFAs) with series connection type is demonstrated. To meet the different demands of front and rear sub‐cells, two NFAs named F‐M and NOBDT with a whole absorption range from 300 to 900 nm are designed, when blended with wide bandgap polymer poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T) and narrow bandgap polymer PTB7‐Th, respectively, the PBDB‐T: F‐M system exhibits a high V_oc of 0.98 V and the PTB7‐Th: NOBDT system shows a remarkable J_sc of 19.16 mA cm^?2, which demonstrate their potential in the TOSCs. With the guidance of optical simulation, by systematically optimizing the thickness of each layer in the TOSC, an outstanding power conversion efficiency of 14.11%, with a V_oc of 1.71 V, a J_sc of 11.72 mA cm^?2, and a satisfactory fill factor of 0.70 is achieved; this result is one of the top efficiencies reported to date in the field of organic solar cells.     

双酚F环氧树脂的改性研究

合成了双酚F/间苯二酚共聚型环氧树脂、二甲基二酚羟基有机烷氧基硅烷,并考察了双酚F/间苯二酚共聚型环氧树脂的性能以及不同二甲基二酚羟基有机烷氧基硅烷用量对双酚F环氧树脂固化物性能的影响.结果发现:改性后的树脂粘度降低,其固化物的耐热性提高,力学性能得到显著改善.     

Thermal behavior of some organic/inorganic composites based on epoxy resin and calcium carbonate obtained from conch shell of Rapana thomasiana

Thermal behavior of some diglycidyl ether of bisphenol A/p-aminobenzoic acid systems with calcium carbonate as a filler were studied. The kinetics parameters of the curing reactions were estimated using the variable peak exotherm method of Kissinger and Ozawa. The most probable kinetic model and the kinetic parameters of the degradation process were also estimated. The energies of crosslinking reactions are situated in the range of 46–57 kJ mol^?1 for the first exotherm and between 68 and 72 kJ mol^?1 for the second exotherm. The cured resins have a good thermal stability and the activation energies of degradation reactions are situated in the range of 178–218 kJ mol^?1.     

氰酸酯/环氧树脂共混物热分解动力学

利用动态TGA方法研究了双酚A二缩水甘油醚环氧树脂和酚醛环氧树脂与双酚A二氰酸酯的两类共混物的热稳定性。用Coats-Redfern研究了不同配比共混物的热分解动力学。结果表明,氰酸酯含量大的双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物具有两阶段分解机理,而环氧含量大的双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物具有均一的热分解活化能;相比较而言,酚醛环氧树脂/双酚A二氰酸酯共混物的分解活化能基本上不随温度和组成变化。从后期失重温度和活化能看,酚醛环氧树脂/双酚A二氰酸酯共混物具有比双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物更高的热稳定性。     

Synthesis and properties of novel photosensitive poly(arylene ether sulfone) containing chalcone moiety in the main chain

A new series of photosensitive poly(arylene ether sulfone)s containing chalcone moiety in the main chain were synthesized from 4,4′-dihydroxychalcone (4DHC), 4,4′-difluorodiphenylsulfone (DFDPS) and bisphenol A (BPA). This series of polymers were characterized by ¹H NMR, FT-IR, UV spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The polymers were stable up to 400 °C, which indicates that the polymers possess good thermal properties. The polymers were found to be soluble in polar solvents and chlorinated solvents. However, the polymers were insoluble in hydrocarbons and in hydroxyl group-containing solvents. After the irradiation of UV light, the thin polymer film was crosslinked to give an insoluble film in the absence of a photoinitiator or sensitizers. The rate of photocrosslinking was also examined and discussed.     

Simultaneous determination of 4-nonylphenol and bisphenol A in sewage sludge

An analytical method has been developed for simultaneous extraction and determination of two estrogenic active agents, 4-nonylphenol (4-NP) and bisphenol A (BPA), in activated sewage sludge and anaerobically stabilized sewage sludge. Both compounds were determined by GC/MS in freeze-dried sewage sludge samples that had been spiked with these compounds in order to indicate different contamination levels. Extractive steam distillation, Soxhlet extraction, supercritical fluid extraction (SFE), and accelerated solvent extraction (ASE) were applied, and the results were compared. ASE under use of ethyl acetate/formic acid and an extraction temperature of 170 degrees C provided the most efficient extraction procedure for simultaneous extraction and the only reliable extraction results. Analyses of the phenolic compounds were performed by capillary column gas chromatography/mass spectrometry (GC/MS), operating in selected ion monitoring (SIM) mode after an aluminum oxide column-cleanup step prior to acetylation. The observed recovery rates under optimized conditions-ASE with ethyl acetate/formic acid-for 4-NP in spiked activated sewage sludge samples (spiking levels: 51, 88, or 554 microg/g on dry weight basis (dwb)) were 90, 107, or 101%. BPA (spiking levels: 50, 87, or 474 microg/g dwb) was found with recovery rates of 70, 105, or 101%, respectively. For anaerobically stabilized sewage sludge, recoveries for 4-NP (spiking levels: 40, 66, or 196 microg/g dwb) were 97, 95, or 101% and 90, 95, or 101% for BPA (spiking levels: 41, 67, or 474 microg/g dwb), respectively.     

On-line nano-HPLC/ESI QTOF MS and tandem MS for separation, detection, and structural elucidation of human erythrocytes neutral glycosphingolipid mixture

A superior approach involving nano-high-performance liquid chromatography (nano-HPLC) in on-line conjunction to electrospray ionization quadrupole time-of-flight mass spectrometry (ESI QTOF MS) and tandem MS for screening and structural characterization of complex mixtures of neutral glycosphingolipids (GSLs) is here described. Neutral GSLs purified from human erythrocytes were efficiently separated according to the differences in carbohydrate chain length by an optimized nano-HPLC protocol and flow-through detected by ESI QTOF MS at the low femtomole level. Additionally, GSL species were accurately distinguished from the accompanying lipids in the mixture, thus permitting the determination of detailed structural characteristics by data-dependent analysis for identification of GSL constitution within single experiments. An alternative nano-HPLC/ESI QTOF MS approach was designed for dissection of unsaturation/saturation degree of the ceramide moieties defining the hydrophobic portion of GSLs and subsequent localization by nano-HPLC/ESI QTOF MS/MS of the -CH=CH- within the ceramide regions. The method is fast, highly sensitive, and high-throughput amenable and is highlighted as a new and valuable analytical dimension in glycolipidomics.     

Estrogenic activity of chemicals for dental and similar use in vitro

The estrogenic activities of chemicals for dental and similar use were tested by a reporter gene assay (yeast two-hybrid system) and an estrogen/estrogen receptor (ER-) competition binding assay (fluorescence polarization system). Among the 10 chemicals [bisphenol-A (BPA), bis-2-hydroxypropyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dibutyl phthalate (DBP), n-butyl benzyl phthalate (BBP), n-butyl phthalyl n-butyl glycolate (BPBG), di-2-ethylhexyl phthalate (DEHP), and di-2-ethylhexyl adipate (DOA)], which were diluted with DMSO to concentrations ranging from 5 × 10^-7 to 5 × 10^-3M, and 17-estradiol (E2) as a positive control, BPA and BBP showed estrogenic activity in these two assays, while the remaining eight chemicals did not at the concentrations tested. Additional data, together with in vivo and epidemiological examinations, are required. Such investigations should also provide information on the validity of these methods for testing the estrogenic activity of chemicals.     

食品金属罐用涂层中双酚 A 的快速定性分析方法

介绍了一种可以快速鉴定食品金属包装用涂料中双酚A的方法。通过分析样品的红外吸收光谱图,比对双酚A结构中特有的5种官能团的特征峰,即可判断出该涂料是否以双酚A为原材料进行加工。该方法快速、简便、准确,符合包装涂料使用者对原材料的定性鉴定要求。     

可见光驱动RGO/g-C3N4活化过硫酸盐降解水中双酚A

光催化氧化法能够高效去除水体中的持久性有机污染物, 在污水净化领域展现出广阔的应用前景。本研究分别以尿素和双氰胺为原料, 采用冷干辅助热聚合法制备了还原性氧化物石墨烯/氮化碳(RGO/g-C₃N₄)二元可见光催化剂, 并对样品的形貌结构和光学性能进行了分析表征。结果表明, 二维层状g-C₃N₄与RGO在异质结界面上紧密的结合在一起。同时以内分泌干扰物双酚A (BPA)为降解污染物, 研究了不同催化剂在可见光下活化过硫酸盐去除BPA的活性。光催化实验结果显示, 在可见光(λ>420 nm)照射下, 加入氧化剂过硫酸盐(PS)作为电子受体, 有效地增强了光催化剂可见光降解BPA的活性。以尿素为原料制备的RGO/g-C₃N₄催化剂在40 min内几乎完全去除溶液中的BPA。经过5次循环反应后, 可见光照射40 min, 该催化剂对BPA的去除率仍能达到80%以上, 表现出良好的稳定性。     

金属有机框架材料MIL-53(Al)-F127对双酚A的吸附性能

采用一步溶剂热法制备具有介孔结构金属有机框架材料MIL-53(Al)-F127，用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、傅里叶红外变换光谱仪(FTIR)、全自动比表面积及孔隙度分析仪(BET)等手段表征其形貌和结构，探究其对双酚A(BPA)的吸附性能并与微孔结构的MIL-53(Al)对比，研究了吸附剂的含量、pH以及温度对其吸附性能的影响。结果表明，介孔结构金属有机框架材料MIL-53(Al)-F127对双酚A具有良好的吸附性能；在pH值为6、温度为30℃条件下MIL-53(Al)-F127在20 min左右达到最大平衡吸附量为27.2 mg/g，去除率达到92%。其吸附动力学模型拟合结果，符合准二级动力学曲线。