氧化活性炭前处理——海米中亚硝酸盐的光度法测定

利用氨基苯磺酸-N-(1-萘)乙二胺光度法,按一般前处理法测定海米中微量亚硝酸盐,标准偏差大,回收率低。本文将试样沉淀蛋白质后用过氧化氢氧化的活性炭处理,并控制试液pH值大于12.5,既能脱色和排除干扰NO_2~-测定的物质以及Cu~(2+)、Pb~(2+)、Ag~+、Hg~(2+)、Bi~(3+)、Fe(3+)等的影响,又能使活性炭不吸附NO_2~-,且使回收率提高到95％以上。8次试样测定结果的相时标准偏差为3.9％。

The Pretreatment of Sample with Oxidised Active Carbon Spectrophotometric Determination of Nitrite in Dried Shrimps

A method is proposed for the determination of micro amounts of nitrite. The pretreatment of sample are used for active carbon that is preprocessed with perhydrol and the sample solution are con-troled above pH 12.5. Under this condition not Only interferences of organic matters and several cations can be eliminated but also nitrite is not absorbed by oxidised active carbon. The method has beea successfully applied to the determination of nitrite in dried shrimps by spectrophotometry. The relative standard deviation is 3.9%. The mean recovery is over 95%.