Simultaneous determination of parathion and p-nitrophenol in vegetable tissues by derivative spectrophotometry

A first derivative spectrophotometric method has been developedfor the determination of parathion and p-nitrophenol in vegetabletissues. Ethanol was used as solvent for extracting the compoundsfrom the tissues and subsequently the samples were evaluated against a vegetable tissue blank, directly by derivative spectrophotometry. The simultaneous determination of these compounds can be carried out using the zero-crossing approach for parathion at 253.0 nm and for p-nitrophenol at 273.1 nm. In the samples each analyte was determined in the presence of one another in the ranges between 4.9 to 3883.5 g g^-1 forparathion and 4.9 to 3285.3 g g^-1 for p-nitrophenol.The detection limits (3) were found to be 1.5 and 1.4 g g^-1 for parathion and p-nitrophenol, respectively. The relative standard deviations were in all instances less than1.8%. The proposed method was applied to the determination ofthe analytes in spiked leafs of corn. The results show a goodrecovery and they are in agreement with those obtained bypolarography.     

氧化淀粉等稀糊淀粉的流度及测定

介绍了淀粉工业中氧化淀粉等稀糊淀粉的流度测定及其意义。     

原子吸收法直接测量土壤中的汞含量

实验采用DMA-80自动测汞仪直接测定土壤中的汞含量,详细介绍了土壤样品中汞分析条件的选择,方法在0．4—400ng范围内,线性良好,其检出限为0．2ug／kg。     

HPLC测定川楝子不同采收期及不同部位中川楝素的含量

通过测定不同采收期和不同部位川楝子中川楝素的含量,为确定川楝子最佳采收期提供依据。采用高效液相色谱法,色谱柱Agilent Zorbax SB-C18（4.6mm×150mm,5μm）,流动相乙腈—水（28∶72）,流速1.0mL/min,检测波长210nm,柱温35℃。不同采收期川楝子中川楝素以1—2月间采收的含量最高;同一采收期的川楝子果核和果肉中川楝素含量最高,外果皮次之,种子中未检出川楝素。     

微型测定法测定白醋中的总酸度

利用微型滴定法测定白醋中的总酸度,并对常量实验和微型实验的测定结果进行了比较分析。结果两种方法无显著性差异,F检验、t检验均在允许范围内,微型实验的准确度和精密度均达到常量实验的测定水平,完全满足化学分析要求,并且有效地节省了实验试剂,大大降低了实验成本。     

高氯低COD值水样的无汞快速测定法

以硝酸银和硫酸铬钾代替硫酸汞来消除 COD 测定中的氯离子干扰,同时将重铬酸钾溶液的浓度降低为0.100 mol／L,并用硫磷混酸代替硫酸,该方法经过对标准样品和实际样品的测定,表现出对于测定氯离子含量低于25000 mg／L的高氯低 COD 值水样具有较好的准确度和精密度,同时可以实现银盐的回收再利用。     

Assessing inter-laboratory comparability and limits of determination for the analysis of cyclic volatile methyl siloxanes in whole Rainbow Trout (Oncorhynchus mykiss)

Cyclic volatile methyl siloxanes (cVMS) are high volume production chemicals used in a wide range of industrial and consumer products. Three cVMS compounds (D4, D5, and D6) have and are undergoing environmental risk evaluations in several countries and have been proposed for legal regulation in Canada. As interest in monitoring concentrations of these chemicals in the environment increase, there is a need to evaluate the analytical procedures for cVMS in biological matrices in order to assess the quality of data produced. The purpose of this study was to determine laboratory testing performance for measuring residues of D4, D5, and D6 in a standard set of fish homogenate samples and to estimate limits of determination for each substance. The samples sent to each laboratory consisted of homogenized whole body tissues of hatchery raised rainbow trout which were fed food fortified with D4, D5, and D6 (dosed) and trout that were fed standard food rations (control). The participants analyzed each sample using their analytical method of choice using their own standards and procedures for quantification and quality control. With a few exceptions, participating laboratories generated comparable results for D4, D5, and D6 in both the dosed and control samples having z-scores between 2 and −2. Method detection limits for the whole fish matrix were on average 2.4 ng g⁻¹ ww for D4, 2.3 ng g⁻¹ ww for D5, and 1.8 ng g⁻¹ ww for D6.     

搁置过夜的青菜汤中的亚硝酸盐氮

通过对搁置过夜的青菜汤中亚硝酸盐氮的测定,来说明搁置过夜的青菜汤不能再吃,以利于人体健康。     

近十年水中硫化物测定方法的进展

评述了１９８５～１９９６年间报道的水中硫化物方法概况，内容包括：水样的预处理方法，水样测定的分光光度法，电化学法，原子吸收光谱以及其他分析方法等。     

土壤中矿物油含量测定方法研究

建立了土壤中矿物油含量的分析方法。采集的土壤鲜样,采用无水硫酸钠进行化学干燥。用四氯化碳提取土壤中的油类物质,采用硅酸镁去除提取液中的动植物油等极性化合物后,使用红外分光测油仪测定提取液中的矿物油含量。此方法具有良好的线性关系,相关系数在0.9999以上。测定下限为1.85 mg/l,测定上限为100 mg/l,测量范围为9 mg/kg～500 mg/kg,方法的灵敏度为1.05。试剂空白加标回收率56%～83%,实际样品加标回收率在69%～74%之间。该法简便快速,灵敏准确,具有广泛的应用前景。