液液萃取结合分散固相萃取-液相色谱串联质谱检测食品包装纸中的4-氨基偶氮苯

采用高效液相色谱-串联质谱法（LC-MS/MS）快速测定食品包装纸中偶氮染料释放的4-氨基偶氮苯.试样在0.5 mol/L氢氧化钠溶液的碱性环境下,用连二亚硫酸钠还原试样中的偶氮染料,用甲基叔丁基醚反萃取还原裂解产生的4-氨基偶氮苯,经氮吹、甲醇复溶后,用液相色谱-串联质谱进行测定,内标法定量.方法优化了色谱分离、质谱、液液萃取和分散固相萃取等条件.最优化条件下方法的检出限为0.13 mg/kg,定量限为0.42 mg/kg,加标回收率在90%~95%之间（添加水平分别为1、10、30 mg/kg）,相对标准偏差小于5%.     

温控离子液体分散液液微萃取结合高效液相色谱法检测脐橙中染色剂残留

建立了QuEChERS-温控离子液体分散液液微萃取结合高效液相色谱法快速检测脐橙中5种染色剂残留的分析方法。QuEChERS前处理步骤:样品用乙腈快速提取,NaCl和无水MgSO4除水后,经N-丙基乙二胺净化。温控离子液体分散液液微萃取步骤:QuEChERS前处理的净化液(1 mL)为分散剂,1-辛基-3-甲基咪唑六氟磷酸盐离子液体(60μL)为萃取剂,55℃水浴12 min,将目标物富集。用高效液相色谱-紫外检测器分析,检出样品用超高效液相色谱-串联质谱确证。在0.01和0.05 mg/kg的添加水平下,5种染色剂的平均回收率为70.3%~93.6%,相对标准偏差为3.5%~9.2%,定量限为1.1~2.8μg/kg。     

超声辅助分散液液微萃取-高效液相色谱法快速测定水样中的6种农药

为实现小体积环境水祥中不同农药的准确、快速、高灵敏测定,通过研究萃取剂、分散剂的种类、体积、盐浓度及超声时间对萃取效率的影响,结合分散液液微萃取与超声萃取技术,并与高效液相色谱联用,建立了快速测定环境水样中的吡虫啉、水胺硫磷、辛硫磷、毒死蜱、哒螨灵和阿维菌素6种农药的方法.在优化的萃取条件下,检测6种农药的线性范围为10～ 600 μg/L,检出限(S/N=3)为0.8～3.1 μg/L,相对标准偏差为4.7％～11.3％,富集倍数可达到58～187倍.本方法具有良好的线性、精密度和回收率,并具有较好的实用性.     

液-液-液微萃取-高效液相色谱法测定人尿液中的美沙酮

建立了液-液-液微萃取与高效液相色谱联用技术快速分析尿样中美沙酮的方法.对有机溶剂种类、体积、样品溶液的pH值、萃取时间、搅拌速度进行了优化.方法的线性范围为0.05～10 mg/L,检出限为0.025 mg/L,相对标准偏差小于5%.     

超声辅助分散液液微萃取/超高效液相色谱-串联质谱法检测水中多种磺胺类抗生素残留

建立了水中13种磺胺类抗生素的超声辅助分散液液微萃取/超高效液相色谱-串联质谱(UADLLME/UPLC-MS/MS)测定方法。以乙腈为分散剂,四氯乙烷为萃取剂,通过超声分散方式协同萃取水样中的目标化合物,采用C_(18)(色谱柱(100 mm×2.1 mm,1.7μm)分离,以乙腈-0.1%甲酸溶液为流动相,采用UPLC-MS/MS多反应监测模式(MRM)测定。优化了萃取剂和分散剂的类型和用量、萃取时间、氯化钠浓度和p H值等条件。在优化条件下,13种磺胺类抗生素在一定质量浓度范围内线性关系良好,相关系数均大于0.998,方法检出限(S/N=3)为0.6~2.4 ng/L;3个加标水平的平均回收率为80.3%~101.8%,相对标准偏差(RSD,n=5)为0.7%~4.5%。该方法前处理简单、环保、灵敏,适用于水样中多种磺胺类抗生素的测定。     

盐析辅助液液萃取/超高效液相色谱－串联质谱法测定含乳饮料中12种邻苯二甲酸酯

建立了基于盐析辅助液液萃取（SALLE）/超高效液相色谱－串联质谱（UPLC－MS/MS）技术检测含乳饮料中12种邻苯二甲酸酯的分析方法。样品采用乙腈提取,硫酸铵作为盐析剂,以苯基色谱柱分离,串联质谱正离子模式扫描,多反应监测模式检测。实验考察了萃取溶剂、盐析剂对萃取效率的影响。最优条件下,12种邻苯二甲酸酯在对应质量浓度范围内线性良好,相关系数（r2）不小于0.997,检出限为0.03 ~ 0.6 μg/kg,定量下限为0.1 ~ 2.0 μg/kg;4种加标浓度下的回收率为70.8% ~ 111%,相对标准偏差为0.30% ~ 7.2%。同时考察了不同温度及光照下聚对苯二甲酸乙二醇酯（PET）包装材质含乳饮料中邻苯二甲酸酯的迁移量,结果表明高温（80 ℃）下邻苯二甲酸二丁酯（DBP）迁移最为显著。该方法操作简捷、成本低、准确度高,可以满足含乳饮料中12种邻苯二甲酸酯的分析要求。     

UPLC-MS/MS对鳗鱼中26种喹诺酮类及磺胺类抗生素药物残留的快速测定

建立了快速测定鳗鱼中喹诺酮类和磺胺类抗生素药物残留量的超高效液相色谱-电喷雾串联质谱方法.采用乙腈-二氯甲烷混合溶剂提取样品中的残留物,经固相萃取小柱净化,以液相色谱-串联质谱仪测定,外标法定量.该法对喹诺酮类和磺胺类药物的线性范围为0 ～50 μg/kg,相关系数均大于0.990;在2.0、5.0、10、20 μg/kg 4个添加水平范围内的回收率为63% ～95%;相对标准偏差为1.0% ～10.0%.适用于鳗鱼中喹诺酮类和磺胺类药物残留的定量测定.     

超高效液相色谱-串联质谱法测定化妆品还原液内的4-氨基联苯

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)检测化妆品还原液中4-氨基联苯的方法.化妆品试样经过连二亚硫酸钠化学还原后,离心、PCX固相萃取小柱提取富集、净化,并经氨化甲醇洗脱、氮吹至近干,定容后通过UPLC-MS/MS仪检测,分离柱为Waters Acquity BEH C18柱;流动相为0.3％乙腈-甲酸水溶液;流速0.5mL/min.5种不同基质中4-氨基联苯在5～250 ng/mL浓度范围内呈良好的线性关系,线性回归系数r2均大于0.999,检测限均为1 ng/mL.5种不同基质中4-氨基联苯的回收率为80.9％～92.6％,相对标准偏差(RSD)为0.51％～3.76％(n=3).     

超声辅助乳化液液微萃取-气相色谱-质谱分析水中的人工合成麝香

将超声辅助乳化与液液微萃取技术结合,建立了水体中人工合成麝香的气相色谱-质谱分析方法.优化前处理条件,包括萃取剂、萃取剂体积、萃取时间、萃取温度及离子强度的选择.结果表明:在10 mL水样中,加入50 μL氯苯作为萃取剂,4 0 MHz超声10 min,混匀,以4000 r/min离心10 min,移取下层有机相进样分析,效果佳.样品的富集倍数可达200倍,8种人工合成麝香在0.005～0.4 μg/L范围内线性关系良好,相关系数均大于0.994;检出限为0.3～0.5 ng/L;水样中加标回收率为96.2％～102.9％;相对标准偏差为2.3％～4.1％.本方法灵敏、快速、准确,可满足环境水样中痕量人工合成麝香监测的质控要求.     

基于低共熔溶剂的分散液液微萃取/超高效液相色谱-串联质谱法测定马肉中非甾体抗炎药

采用氯化胆碱和苯酚合成低共熔溶剂(DES),以其为萃取剂建立了分散液液微萃取(DLLME)结合超高效液相色谱-串联质谱(UPLC-MS/MS)测定马肉中10种非甾体抗炎药的方法。优化了提取溶剂、萃取剂、分散剂和盐的加入量等条件,最佳萃取条件为：以氯化胆碱和苯酚(比例为1∶2)合成的低共熔溶剂为萃取剂,马肉样品经5 mL含10 mmol/L抗坏血酸的20 mmol/L醋酸铵缓冲液(乙酸调至pH 3.5)提取,加入1.0 g氯化钠、0.8 mL萃取剂和0.8 mL分散剂,旋涡混合1 min,离心后取上清液经超高效液相色谱-串联质谱测定,外标法定量。结果显示,10种非甾体抗炎药在各自质量浓度范围内呈良好线性关系,相关系数(r2)均大于0.996,检出限为0.05~2.0 μg/kg,定量下限为0.10~5.0 μg/kg,平均回收率为73.5%~94.6%,相对标准偏差(RSD)为1.1%~8.1%。该方法操作简单、准确高效、绿色环保,可用于马肉中非甾体抗炎药的测定。     

Speciation and Determination of Trace Amount of Inorganic Arsenic in Water,Environmental and Biological Samples

A new speciation and preconcentration method based on dispersive liquid‐liquid microextraction has been developed for trace amounts of As(III) and As(V) in urine and water samples. At pH 4, As(III) is complexed with ammoniumpyrrolidine dithiocarbamate and extracted into 1‐Hexyl‐3‐methylimidazolium hexafluorophosphate, as an ionic liquid (IL) and As(III) is determined by electrothermal atomic absorption spectrometery (ETAAS). Arsenic(V) in the mixing solution containing As(III) and As(V) was reduced by using KI and ascorbic acid in HCl solution and then the procedure was applied to determination of total arsenic. Arsenic(V) was calculated as the difference between the total arsenic content and As(III) content. The effect of various parameters on the recovery of the arsenic ions has been studied. Under the optimum conditions, the enrichment factor 135 was obtained. The proposed method was successfully applied to the determination of trace amounts of As(III) and As(V) in water and biological samples.     

甲壳型液晶高分子的构筑、自组装及其功能化

甲壳型液晶高分子的发展很大程度上依赖于聚合物自组装的发展,而各种可设计、可预测、可调控的自组装策略的涌现,将甲壳型液晶高分子研究推向前所未有的高度,同时也极大地丰富了高分子化学与物理的内容,提升了研究水准.研究表明,侧链"甲壳效应"在调控甲壳型液晶高分子有序结构等方面有着重要作用.本综述从甲壳型液晶高分子设计合成、液晶相态调控、嵌段共聚物自组装和功能化应用等方面,总结和评述了近年来该领域国内的最新研究进展.最后,本综述总结了甲壳型液晶高分子在发展中所面临的主要问题,并对其发展趋势进行了展望.     

GBS-307C型硅、锰、磷、铬、镍、铜等多元素自动分析仪的研制

为解决黑色金属材料中硅、锰、磷、铬、镍、铜、钼、钛、稀土、镁等元素含量（质量分数）的自动分析,设计了GBS-307C型多元素自动分析仪。该仪器根据流体力学原理自动定量加入和分取试液,常温显色法进行被测元素的化学反应,计算机完成仪器程序控制及工作曲线建立和数据处理等。用研制的分析仪对标准样品进行测定,测定结果与标准值相符合。     

液体橡皮泥:属性特征、制备策略及应用探索

液体橡皮泥是指空气环境中被颗粒包裹的以可塑性和复杂形状为特征的液体系统,目前已被成功应用于气体传感、蛋白质分析、光催化等领域,并展现出了很多独特优势。这是一种新兴的软物质体系,与被颗粒包裹的形状为类球形的液体弹珠组成相似,但打破了后者的形状单一性。本文从裸液滴和液体弹珠出发,通过对液体形状和颗粒堵塞问题的分析,梳理了液体橡皮泥技术的建立过程。随后,论述了国内外的研究进展,对不同种类液体橡皮泥的制备、特性及应用进行了概括和分析,重点讨论了单层纳米颗粒结构液体橡皮泥的系列研究。最后,围绕液体橡皮泥的概念内涵、制备方法、特性对比、功能应用等问题进行了总结和探讨,并就未来发展方向和研究思路提出了建议。     

Comparison of the performance of conventional, temperature-controlled, and ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography in analyzing pyrethroid pesticides in honey samples

This research paper presents a comparative study of the performance of conventional, ultrasound-assisted (UA), and temperature-controlled (TC) ionic liquid (IL) dispersive liquid-phase microextraction (IL-DLLME). Various parameters that affect extraction efficiency, such as type and volume of extraction and disperser solvent, centrifugation time, salt addition, effect of temperature on TC-IL-DLLME, and effect of sonication time on UA-IL-DLLME, were evaluated. UA-IL-DLLME was found to provide the best extraction efficiency. Under optimized conditions, great enrichment factors (506-515) and good recoveries (101.2-103.0%) were obtained by analyte extraction in real samples. The limit of detections (LODs) ranged from 0.21 to 0.38 μg L(-1). Good linearity was obtained in the range of 0.5-200 μg L(-1) for ethofenprox and tetramethrin, and 1-200 μg L(-1) for meperfluthrin and alpha-cypermethrin. Based on optimized conditions, the UA-IL-DLLME method was applied and combined with high-performance liquid chromatography with diode array detection (HPLC-DAD) to determine the presence of ethofenprox, tetramethrin, meperfluthrin, and alpha-cypermethrin in honey samples.     

Preparation and properties of highly birefringent liquid crystalline materials: styrene monomers with acetylenes,naphthyl, and isothiocyanate groups

Two new series of styrene monomers with different alkyl chain length were successfully synthesised. The chemical structures of synthetic intermediates and monomers were confirmed by Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. Their thermal stability, transition temperatures and phase sequences were investigated by polarised light microscopy, thermogravimetric analysis, differential scanning calorimetry and one-dimensional wide-angle X-ray diffraction. The birefringent and photoelectric properties, UV–vis and fluorescence spectroscopy were also measured using Abbe refractometer and fluorescent apparatus. The results indicated that all the monomers exhibited a liquid crystalline phase at higher temperature, high birefringence values between 0.4 and 0.7, and good photoluminescence properties. Optical anisotropy of homologous molecules was reduced with the increase of alkyl chain length due to the decrease of molecular polarisation. Moreover, a significant effect of the chemical structure on the photoluminescence properties was also found and discussed according to the length of π-conjugation.     

Design,synthesis, and characterisation of symmetrical bent-core liquid crystalline dimers with diacetylene spacer

Two new symmetrical bent-core liquid crystalline dimers (B-DA4 and B-DA12) bearing diacetylenes spacer and different terminal alkyl chains were successfully synthesised via Sonagashira coupling reaction. The molecular structures of these dimers were confirmed by ¹H nuclear magnetic resonance (NMR), Fourier transform-infrared spectroscopy (FT-IR), Raman spectroscopy, mass spectrometry, and elemental analysis. Their thermal stability and liquid crystalline properties were characterised by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarised light microscopy (PLM), and small-angle X-ray scattering (SAXS). Results showed that the diacetylene group may be thermal polymerised at about 260°C far from thermal decomposition. The dimers exhibited monotropic phase behaviour and typical layered-structure phase with long-range order on a length scale of about 6.3 nm was observed. The results mentioned above offer a promising opportunity to design polydiacetylene nanowires by thermal, UV irradiation, or scanning tunnelling microscope (STM) tip-induced polymerisation.     

Room-Temperature Laser Synthesis in Liquid of Oxide,Metal-Oxide Core-Shells,and Doped Oxide Nanoparticles

Although oxide nanoparticles are ubiquitous in science and technology, a multitude of compositions, phases, structures, and doping levels exist, each one requiring a variety of conditions for their synthesis and modification. Besides, experimental procedures are frequently dominated by high temperatures or pressures and by chemical contaminants or waste. In recent years, laser synthesis of colloids emerged as a versatile approach to access a library of clean oxide nanoparticles relying on only four main strategies running at room temperature and ambient pressure: laser ablation in liquid, laser fragmentation in liquid, laser melting in liquid and laser defect-engineering in liquid. Here, established laser-based methodologies are reviewed through the presentation of a panorama of oxide nanoparticles which include pure oxidic phases, as well as unconventional structures like defective or doped oxides, non-equilibrium compounds, metal-oxide core–shells and other anisotropic morphologies. So far, these materials showed several useful properties that are discussed with special emphasis on catalytic, biomedical and optical application. Yet, given the endless number of mixed compounds accessible by the laser-assisted methodologies, there is still a lot of room to expand the library of nano-crystals and to refine the control over products as well as to improve the understanding of the whole process of nanoparticle formation. To that end, this review aims to identify the perspectives and unique opportunities of laser-based synthesis and processing of colloids for future studies of oxide nanomaterial-oriented sciences.     

Low temperature polymerization of novel,monotropic liquid crystalline benzoxazines

Cationic ring opening polymerization at a lower temperature range/faster polymerization than ordinary benzoxazine resins has been achieved without added initiators or catalysts via liquid crystalline (LC) benzoxazine resins. Faster polymerization is observed even above the liquid crystal forming temperature. The FTIR spectra show that opening of the oxazine ring occurs even at 110 °C generating phenolic groups that auto‐catalyzed the cationic polymerization of the monomer increasing the rate of polymerization. The newly formed H‐bonds inhibit the formation of LC phases after polymerization. Some of the monomers show nematic LC transitions upon cooling. None of them showed LC transitions during the heating cycle, exhibiting monotropic LC phases. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5871–5881, 2009     

Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid–liquid microextraction combined with HPLC

A novel, simple, and rapid method is presented for the analysis of aflatoxin B₁, aflatoxin B₂, and ochratoxin A in rice samples by dispersive liquid–liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid–liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B₁ and B₂. Parameters affecting both extraction and dispersive liquid–liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06–0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9–112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China.