建立了一种酶法检测食品中柠檬酸含量的快速检测方法.将6UL-苹果酸脱氢酶、9.13 U L-乳酸脱氢酶、0.5 mg烟酰胺腺嘌呤二核苷酸、2 mg硫酸镁、3.783 mg海藻糖、5mg聚乙二醇6000在0.2 mL 0.082 g/mL双甘肽质量浓度下-60℃冷冻5h,室温条件下抽真空18h得到试剂Ⅰ,0.468U柠檬酸裂解酶在0.2 mL水体系冷冻干燥得到试剂Ⅱ.结果表明,该方法标准曲线线性关系良好,相关系数R2=0.995,线性范围1～80 μg/L;灵敏度0.25 mg/L;检测限0.5 mg/L;各样品回收率均在90％～110％.该试剂盒方法可以在20 min实现样品中柠檬酸的快速检测,方法灵敏度高、特异性高、快速简便,适合于食品生产企业对食品中的柠檬酸进行快速检测及对食品的质量和品质进行评价.

本试验建立了一种超高效液相色谱—电喷雾串联质谱测定鸡肉中金刚烷胺的分析方法.以甲醇1％三氯乙酸作提取剂,采用超声波辅助溶剂萃取法萃取鸡肉中金刚烷胺,萃取液用MCX固相萃取柱进行净化浓缩.以BEH C18色谱柱为分离柱,在正离子模式下以电喷雾电离串联质谱仪进行测定.对质谱和色谱条件、提取剂的种类、超声提取时间、固相萃取柱及洗脱液的种类进行了优化,在0.1～20.0 ng/mL范围内线性关系良好(r=0.9998).样品在5.0、10.0和20.0μg/kg添加水平的回收率为89.7％～101.4％,相对标准偏差(RSD)小于7.0％;方法的检测限为0.07 μg/kg,定量限为0.23 μg/kg.本方法灵敏度高、准确度高,能满足公司及相应鸡肉行业的客户进行鸡肉中金刚烷胺残留量的快速、高灵敏检测分析.本试验还根据金刚烷胺在动物体内的代谢动力学成功制备了浓度为11.16和7.18mg/kg的金刚烷胺阳性鸡肉样品,为研发金刚烷胺ELISA试剂盒提供了相应的阳性样品.

<正>苏丹红是一种人工合成的偶氮类染色剂,有Ⅰ、Ⅱ、Ⅲ、Ⅳ号[1]。苏丹红不是一种食品添加剂,但是由于其着色效果好、颜色比较鲜艳,被许多食品厂商作为食品添加剂加入食品中来增加食品的颜色。国际癌症研究机构将苏丹红归为三类致癌物质,但苏丹红的代谢产物却属于二级致癌物质。还有研究表明,苏丹红能诱发癌细胞的产生,可能会使肝部

A novel method was developed for the determination of ranitidine by high performance liquid chromatography(HPLC) with chemiluminescence(CL) detection.The chromatographic separation was performed on a Hypersil BDS-C18 column(i.d.: 250 mm×4.6 mm,particle size: 5 μm,pore size: 100) with an isocratic mobile phase consisting of methanol and 0.02 mol/L KH2PO4(pH 3.0)(volume ratio 35:65) at a flow rate of 1.0 mL/min.The detection was based on the chemiluminescence reaction of ranitidine with acidic potassium permanganate(KMnO4) and tris(2,2(-bipyridyl)ruthenium(III),which was immobilized on the cationic ion-exchange resin.Under optimum conditions,the linear range for ranitidine was 2.0×10-4～4.0×10-2 mg/mL with the detection limit of 67 ng/mL(3σ).The relative standard deviation(RSD) was 2.2%(n=11) for 2.0 μg/mL ranitidine.Ranitidine in the serum samples was analyzed by the proposed method with satisfactory results.

A new molecularly imprinted polymer (MIP)–chemiluminescence (CL) method has been developed for detection of proline. The molecularly imprinted polymer microspheres were synthesized using precipitation polymerization with hydroxyproline, a structural analogue, as the template. Polymer microspheres were immobilized in microtiter plates (96 wells) which selectively adsorbed the analyte (dansyl-proline). After washing, the bound fraction was quantified based on peroxyoxalate chemiluminescence (PO-CL) reaction enhanced by imidazole. The cavity of MIP synthesized with hydroxyproline as template is smaller, which can avoid non-specific adsorption and lead to enhancement of specificity, response speed and sensitivity when recognizing dansyl-proline. Under the optimum conditions, the relative CL intensity has a linear relationship with the concentration of proline in the range of 1 × 10−6 mol L−1 to 4 × 10−5 mol L−1, with a limit of detection 3 × 10−7 mol L−1 (3σ). The relative standard deviation (R.S.D.) for proline (1 × 10−6 mol L−1, n = 7) was 3.7%. The MIP–CL method can become a useful analytical technology for determination of proline in real sample.

A novel enzyme reactor was prepared using calcium alginate fiber (CAF) and amine-modified nanosized mesoporous silica (AMNMS) as a support. Combination of the adsorption of the enzyme on AMNMS with the cage effect of the polymer greatly increases the catalytic activity and the stability of the immobilized enzyme. It was shown that the lifetime, stability, and catalytic activity of the enzyme reactor were greatly improved by incorporating AMNMS into CAF to efficiently encapsulate the enzyme. Glucose oxidase was chosen as a model enzyme to explore the possibility of using CAF–AMNMS as a matrix for enzyme immobilization in the design of a chemiluminescence (CL) flow-through biosensor. The sensitivity of the flow-through biosensor combined with a novel luminol-diperiodatonickelate CL system was higher than for other reported CL biosensors. The proposed biosensor exhibits short response time, easy operation, long lifetime, high catalytic activity, high sensitivity, and simple assembly.

羟脯氨酸(Hydroxyproline,HYP)是一种非必需氨基酸,主要存在于胶原组织中,是构成胶原的重要成分之一,作为胶原蛋白中的特异性氨基酸,可以反映机体中胶原蛋白含量的变化,而胶原蛋白含量变化又与许多疾病有关,如烧伤、创伤后的修复、骨质疏松、肝硬化、肺纤维化、肾纤维化、肿瘤等,因此测定血液中游离羟脯氨酸含量有重要临床意义.

A new molecularly imprinted polymer (MIP)-chemiluminescence (CL) detection approach towards recognition of dansyl-glycine (Gly) is presented. The polymer microspheres were synthesized using precipitation polymerization with glycine as template and immobilized in microtiter plates (96 wells) using poly(vinyl alcohol) (PVA) as glue. The analyte (dansyl-glycine) was selectively adsorbed on the MIP microspheres. After washing, the bound fraction was quantified based on a dansyl-glycine-bis(2,4,6-trichlorophenyl) oxalate (TCPO)-H2O2 chemiluminescence reaction enhanced by imidazole. The chemiluminescence intensity has a linear relationship with the concentration of glycine in the range of 0.2 similar to 60 mu mol/L, with the limit of detection (LOD) being 0.07 mu mol/L (3 sigma). The relative standard deviation (RSD) for 11 parallel measurements of glycine (1 mu mol/L) was 3.3%. The cavity of MIP synthesized with glycine as template is smaller, which can avoid non-specific adsorption and lead to enhancement of specificity, response speed and sensitivity when recognizing dansyl-glycine.