Frustrated magnetic structure of TmAgGe

Physical properties of the compound TmAgGe have been investigated by means of magnetometric, transport, calorimetric as well as neutron diffraction measurements. The compound crystallizes in the hexagonal ZrNiAl-type crystal structure. The reported results indicate that the sample exhibits an antiferromagnetic ordering below . The low temperature behavior of the magnetic susceptibility and the specific heat is in good agreement with the spin-wave theory with linear dispersion relation. In addition, the magnetic structure of TmAgGe was determined by means of neutron diffraction measurements. The Tm moments are equal to 6.44(10) μ_B at 1.5 K and form a non-collinear magnetic structure within the basal plane. To describe this structure three different propagation vectors: , and are required. Such a spin arrangement is analyzed on the basis of group theory.     

含氟基团对液晶垂直排列的作用

实验发现双酚A双肉桂酸酯和六氟双酚A双肉桂酸酯单体在线偏振紫外光作用下发生光交联,形成的薄膜对液晶分子的排列效果截然不同,分别诱导液晶分子沿面平行排列和垂直排列.红外光谱分析表明光交联的类型均为[2+2]环加成反应.利用原子力显微镜观察薄膜表面,没有发现明显的各向异性拓扑分布.通过测量非含氟和含氟两种交联膜的表面能大小,发现氟的引入使薄膜的表面能降低,同时表面能中的极性作用明显降低.实验结果表明,氟基团的引入导致液晶分子垂直排列.本文探讨了这种垂直排列的原因.     

An immunoassay for bisphenol A based on direct hapten conjugation to the polystyrene surface of microtiter plates

Based on direct hapten coated format a competitive indirect enzyme-linked immunosorbent assay (ciELISA) for bisphenol A (BPA) was developed. Polystyrene surface was modified by 3-Aminopropyltriethoxysilane (APTES) to produce amino groups after H₂SO₄/HNO₃-pre-treatment. 4,4-bis (4-hydroxyphenyl) valeric acid (BVA) which is analogue of BPA, was successfully immobilized on the surface of microtiter plates by N,N′-dicyclohexylcarbodiimide (DCC) method. The essential steps of the assay were optimized, especially blocking procedure which is key step to prevent unspecific binding of antibody. The results indicated that compared with hapten-protein coated format (IC₅₀ = 176.67 ng ml⁻¹, LOD = 15.90 ng ml⁻¹), the direct hapten coated format (IC₅₀ = 23.50 ng ml⁻¹, LOD = 0.27 ng ml⁻¹) could improve assay sensitivity and the detection ranges were 2.30 ng∼157.60 ng ml⁻¹ with good signal reproducibility (P value > 0.05) after careful optimization of assay conditions. Tap water samples and seawater samples were spiked with a known amount of BPA and measured by ciELISA. The average recoveries were between 70 and 142%. As far as we are aware this is the most sensitive ELISA for BPA yet reported.     

Sensitive Voltammetric Determination of Bisphenol A Based on a Glassy Carbon Electrode Modified with Copper Oxide‐Zinc Oxide Decorated on Graphene Oxide

A highly sensitive and selective chemical sensor was prepared based on metallic copper‐copper oxides and zinc oxide decorated graphene oxide modified glassy carbon electrode (Cu?Zn/GO/GCE) through an easily electrochemical method for the quantification of bisphenol A (BPA). The composite electrode was characterized via scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of BPA in Britton‐Robinson (BR) buffer solution (pH 7.1) was examined using cyclic voltammetry (CV). Under optimized conditions, the square wave voltammetry (SWV) response of Cu?Zn/GO/GCE towards BPA indicates two linear relationships within concentrations (3.0 nmol L^?1?0.1 μmol L^?1 and 0.35 μmol L^?1?20.0 μmol L^?) and has a low detection limit (0.88 nmol L^?1). The proposed electrochemical sensor based on Cu?Zn/GO/GCE is both time and cost effective, has good reproducibility, high selectivity as well as stability for BPA determination. The developed composite electrode was used to detect BPA in various samples including baby feeding bottle, pacifier, water bottle and food storage container and satisfactory results were obtained with high recoveries.     

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

Degradation of endocrine disruptor bisphenol A by ultrasound-assisted electrochemical oxidation in water

Micropollutants are becoming an increasing problem for the environment and wastewater treatment. One example is Bisphenol A (BPA), an endocrinic disruptor, which is widely used in plastic production. Due to its endocrine disrupting effects on aquatic (micro-)organisms and its ubiquity, in surface- and wastewater alike, adequate treatment techniques are necessary.In this study, the degradation of BPA by a sonoelectrochemical hybrid system was investigated, using a low frequency (24 kHz) ultrasound horn and two boron doped diamond electrodes. It was found that by the combination of the individual processes, i.e. ultrasound and electrochemical oxidation, more than 90% of BPA could be removed within 30 min at an initial concentration of 1 mg L⁻¹. Moreover, synergistic effects were discovered and a considerable improvement compared to the individual processes could be achieved by using a potential of 5 V, whereas synergistic effects were absent at a potential of 10 V. This study provides investigation of ultrasound amplitude, potential and electrode positioning on BPA degradation. The reaction was found to follow pseudo first order kinetics with a rate constant of 0.089 min⁻¹. Samples were analysed by high pressure liquid chromatography (HPLC) using a diode array detector. Moreover, the presence and distribution of hydroxyl radicals within the reactor was visualized by using sonochemiluminescence.     

双酚A在壳聚糖-FC-134-碳纳米管修饰电极上的电化学行为及其测定

采用十二烷基硫酸钠(SDS)与全氟辛基磺酰季碘化物FC-134作为碳纳米管的复合分散剂,制备了壳聚糖-碳纳米管修饰电极(MFC/GCE)。研究了环境激素双酚A在pH 8.0磷酸盐缓冲溶液中的电化学行为,并探讨了其电极过程机理。峰电位为0.450 V,峰电流与其浓度在2.5×10-7~1.0×10-4mol/L范围内呈线性关系,检出限为1.0×10-8mol/L。该法用于环境水样中双酚A含量的测定并与荧光法对照,测定结果吻合。     

含有脂肪族侧链的聚醚醚酮的合成、表征及结构与性能关系

以苯酚和含有不同链长的长链脂肪酮作为原料, 制备了与双酚A结构相似的双酚单体, 并与4, 4'-二氟二苯酮共聚, 合成了几种含有不同长度脂肪族侧链结构的聚醚醚酮类(PEEKs)聚合物. 利用元素分析和核磁共振氢谱(1H NMR)对所合成的双酚单体进行了表征, 并用红外光谱(FTIR)\, 示差量热扫描仪(DSC)、热失重分析仪(TGA)和电子拉力机对所合成的聚合物结构和性能的关系进行了研究.     

分散液-液微萃取/高效液相色谱法测定水样中的痕量双酚A

建立了分散液-液微萃取与高效液相色谱联用技术测定水样中痕量双酚A(BPA)的方法. 通过对实验条件的筛选及优化, 得到最佳条件: 22.5 μL氯苯作萃取剂、0.5 mL丙酮作分散剂、0 min静止萃取时间、调节pH 3.2左右、10%离子强度及9 mL水样体积. 此条件下方法的线性范围为0.5~100 μg/L(R2=0.9941), 检出限为0.10 μg/L. 在BPA质量浓度为1 μg/L条件下, 方法回收率为87.8%~111.0%, 相对标准偏差8.3%(n=5), 富集倍数范围1905~2527. 对添加不同BPA浓度的自来水、地表水及回用中水进行分析, 回收率分别为(108±11.1)%, (107±13.2)%及(81.2±6.2)%(n=3). 在既定的色谱条件下, BPA的测定不受乙炔基雌二醇、雌二醇、雌三醇、雌酮和壬基酚等雌激素的干扰.     

基于儿茶酚交替共聚物的干湿态双高效胶黏剂材料

以多巴胺(DA)和双酚A型环氧树脂(BAER)进行氨基-环氧点击化学反应,合成了儿茶酚功能化交替共聚物聚(多巴胺-alt-双酚A型环氧)[P(DA-a-BAER)].以FeCl₃为交联剂,研究了交联剂用量对聚合物在干态及水下环境中黏接性能的影响.结果表明,该聚合物可以在干态及水下环境中对多种基材进行黏接.以不锈钢基材为例,在干态条件下,当Fe³⁺与儿茶酚基团的摩尔比为1:3时,黏接强度最高,为(3.03±0.68)MPa;在水下环境中,当Fe³⁺与儿茶酚基团的摩尔比为1:6时,黏接强度最高,为(0.65±0.10) MPa.拉曼光谱(Raman)和紫外-可见光吸收光谱(UV-Vis)分析结果表明,Fe³⁺与儿茶酚基团可通过配位交联和氧化交联的方式增大胶体强度,从而提高黏接强度.