提高分光光度法测定乳粉亚硝酸盐回收率的研究

Study on Improving the Spectrophotometer Recovery of Nitrite in Milk Powder

依据《食品安全国家标准食品中亚硝酸盐与硝酸盐的测定》(GB 5009.33—2016)第二法分光光度法测定乳粉亚硝酸盐的加标回收率普遍偏低,影响测定结果准确性。本文通过探索、优化提取过程,发现每10 g样品称样量中各添加8 mL蛋白沉淀剂时,可以显著提高提取效率;且当称样量≥3 g时,称样量的减少可以有效降低乳粉中基质颜色对吸光度测定的影响,从而提高分光光度法测定乳粉中亚硝酸盐的回收率。

According to GB 5009.33—2016, the standard addition recovery rate of nitrite in milk powder determined by the second method of spectrophotometry is generally low, which affects the accuracy of determination results. By exploring and optimizing the extraction process, it was found that when 8 mL protein precipitant was added to each 10 g sample weight, the extraction efficiency could be significantly improved;and when the sample weight is ≥ 3 g, the reduction of the sample weight can effectively reduce the influence of the matrix color in the milk powder on the absorbance measurement, thereby improving the recovery rate of nitrite in the spectrophotometric determination of milk powder.