基于聚硫堇膜对DNA杂交的直接电化学检测

In this work, the application of a conducting polymer, poly（thionine）, modified electrode as matrix to DNA immobilization as well as transducer to label-free DNA hybridization detection was introduced. The electropolymerization of thionine onto electrode surface was carried out by a simple two-step method, which involved a preanodization of glassy carbon electrode at a constant positive potential in thionine solution following cyclic voltammetry scans in the solution. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity potential domain of poly（thionine）. The resulting poly（thionine） modified electrode showed a good stability and electroactivity in aqueous media during a near neutral pH range. Additionally, the pendant amino groups on the poly（thionine） chains enabled poly（thionine） modified electrode to immobilize phosphate group terminated DNA probe via covalent linkage. Hybridization process induced a clear decrease in poly（thionine） redox current, which was corresponding to the decrease in poly（thionine） electroactivity after double stranded DNA was formed on the polymer film. The detection limit of this electrochemical DNA hybridization sensor was 1.0 × 10^-10mol/L. Compared with complementary sequence, the hybridization signal values of 1-base mismatched and 3-base mismatched samples were 63.9% and 9.2%, respectively.     

饮用水中9种痕量亚硝胺类化合物的分析方法研究

建立了9种亚硝胺类化合物(NDMA,NMEA,NDEA,NDPA,NDBA,NPiP,NPyr,NMor,NDphA)的SPE-UPLC-MS检测方法.优化了流动相、离子源、萃取柱、样品保存条件、样品保存时间5个条件,实验结果表明:流动相使用0.1％(V/V)的甲酸水和甲醇,仪器响应最好;活性炭萃取柱萃取除NDPhA的8种物质,使用大气压电离源(APCI)测定;HLB萃取柱萃取NDphA,使用电喷雾电离源(ESI)测定;样品使用硫代硫酸钠进行脱氯保存;样品在7d之内进行测定.对纯水、地表水、出厂水中的9种亚硝胺化合物进行加标测定,回收率范围为72.0％～128.9％,精密度范围为0.7％ ～20％.     

电感耦合等离子体质谱法测定包装材料中10种有毒元素

建立电感耦合等离子体质谱法测定包装材料中铬,镍,铜,锌、砷、硒、钼、镉、汞、铅10种有毒元素的方法。以硝酸和过氧化氢为消解试剂,采用微波消解法消解样品,在选定的仪器工作条件下进行测定。汞的质量浓度在1～10μg/L范围内,其它9种元素的质量浓度在1～100μg/L范围内与质谱响应值具有良好的线性关系,相关系数均不小于0.999 7,方法检出限为0.000 3～0.027 6 mg/kg。塑料和纸质包装材料样品中10种元素测定结果的相对标准偏差为1.10%～4.44%(n=7),样品加标回收率为85.17%～106.16%。该方法适用于包装材料中多种元素的同时测定。