摘要
采用在线透析和在线镉柱还原-流动注射光度法测定乳品中的硝酸盐和亚硝酸盐。乳品与温热的氯化铵缓冲液混合,通过离心和快速冷却除去脂肪,通过在线透析除去蛋白质和残余的脂肪。方法基于测定亚硝酸盐与4-对氨基苯磺酰胺、N-(1-萘基)乙二胺盐酸盐形成偶氮染料的吸光度,硝酸盐经镀铜的镉柱还原为亚硝酸盐,得到硝酸盐与亚硝酸盐含量的总和。在20.0～2000.0μg/LN的浓度范围内,硝酸盐和亚硝酸盐均可获得良好的线性(r≥0.999)。此方法的检出限低,硝酸盐和亚硝酸盐的检出限分别为4.4μg/LN、2.3μg/LN,相对标准偏差分别为2.0%～5.8%、0.2%～3.5%,样品测定频率分别为40样/h、60样/h,实际乳制品的加标回收率分别为94%～101%、91%～107%。此方法简单快捷,对于实际乳制品的测定结果令人满意。
Using on-line dialysis and cadmium reduction flow injection analysis method to determine nitrate and nitrite in milk products.A test portion was mixed with a warm extraction ammonium buffer solution.Fat was separated by centrifuging and rapid cooling.on-line dialysis was used to remove protein and remaining fat.The method was based on absorbance measurement of azo dye obtained by the reaction of nitrite with N-（1 naphthyl） ethylenediamine dihydrochloride and sulfanilamide.Nitrate was reduced to nitrite in a copperized cadmium column to obtain the concentration of nitrite plus nitrate.Linear calibration curves was obtained for the concentration range was 20.0～2000.0 μg/L N（r≥0.999） for both of nitrate and nitrite.The proposed method had low detection limit of nitrate was 4.4 μg/L N and of nitrite was 2.3 μg/L N.The relative standard deviation was 2.0%～5.8% and 0.2%～3.5% with the sample throughput of was 40 samples/h and 60 samples/h for nitrate and nitrite respectively.Nitrate and nitrite were determined in the real samples of various milk products with the recovery of nitrate was 94%～101% and of nitrate was 91%～107%.The method was simple,rapid and has been used to the determination of nitrate and nitrite in milk products with satisfactory results.
出处
《食品科技》
CAS
北大核心
2010年第7期296-299,共4页
Food Science and Technology
基金
国家科技部"十五"科技攻关项目(2004BA210A05)
