新鲜蔬菜硝酸盐含量测定的改进试粉法

 为适应新鲜蔬菜硝酸盐快速检测的需要, 在现有试粉法的基础上对硝酸盐测定的试粉法进行了改良研究。结果表明, 本研究建立的直接以去离子水浸提蔬菜匀浆, 混合试粉配方为柠檬酸∶一水硫酸锰∶无水对氨基苯磺酸∶N - 1 - 萘乙二胺盐酸盐∶细锌粉= 30∶4∶1.6∶0.8∶1, 其加入量为0.1 g的改进试粉法, 对于溶液中硝酸盐含量在0～20 mg/L范围时, 显色吸光值与硝酸盐含量呈现良好的线性关系, 相关系数达0.9999, 方法回收率在97.7%～104.5%之间, 相对标准偏差2.71%。用本改进试粉法测定11种蔬菜的硝酸盐含量与国标法测定结果的t检验具有一致性。

A Improved Testing Powder Method for Rapidly Determining Nitrate Content in Fresh Vegetable

A new improved approach of testing powder method for rapidly determining nitrate content in fresh vegetable was studied. The results showed that the absorbance value at 538 nm had a good linearitywith the nitrate content in the range 0 - 20 mg/L with the relationship coefficient 0.9999, the recovery 97.7 % - 104.5% , and RSD 2.71% , when the extracting solvent 2% HAc in current method was substituted by H₂O, the ratio of testing powder consisting of citric acid monohydrate, manganese sulfate monohydrate, P-aminobengene sulponie acid anhydrous, N₂ (1-naphthyl) ethylenedianine dihydrochloride and zinc powder was 30∶4∶1.6∶0.8∶1, and the quantity added was 0.1 g. The nitrate contents in eleven vegetable species determined by this method were not significantly different from those determined by the national standard test method.