摘要
用硝酸根电极同时测定肉制品中硝酸盐和亚硝酸盐含量。以0.1mol/l硫酸钠作为总离子强度调节剂,在pH3.4±0.1,硝酸根电极在硝酸钠4.0—30μg/ml浓度范围内呈良好的能斯特应答。一次标准加入法定量。在酸性条件下,用过氧化氢氧化提取液中NO_2^-,测得NO_3^-总量,然后用差减法求得NO_2^-含量。用本法测定了13种市售肉制品中硝酸盐和亚硝酸盐含量。变异系数2.31%—9.83%,回收率95.0%—108.4%。用NO_3^-和镉柱还原法,NO_2^-和萘乙二胺比色法进行了对照,结果无显著性差异(α0.05)。
The determination of nitrate and nitrite in meat produets by I. S. E. is investigated. The chloride in the sample isolate is precipited with silver sulfate. Aluminium sulfate, orthoboric acid and sulfoamidic acid and sulfoamidic acid are are added to eliminate the interference of organic acid anion and nitrate in the filtrate. 0.1 mol. sodium sulfate is used as T. I. S. A. B. At pH 3.4±O.1. the response of nitrate electrode is line up to 4.0-30 NaNO-3 μg/ml. On the other hand, hitrite in the isolate is oxided with hydrogen peroxid at acidic condition. Then the nitrite is determined by different methods. The concentration of nitarite and nitrite inthirteen meat products is determined by applying the standard addition method. The precision and recovery of this method are within 2.31%—9.83% and 95.0%—108.4% respectively.
