离子色谱法同时测定海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐

Simultaneous Determination of Nitrate, Nitrite and Polyphosphates in Seafood by Ion Chromatography

建立超声辅助提取离子色谱法测定海产品中硝酸盐、亚硝酸盐和多聚磷酸盐(包括正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐)含量的方法,对样品中硝酸盐、亚硝酸盐和多聚磷酸盐的稳定性进行研究,并采用该法对典型海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐含量进行测定。结果表明:采用亲水性阴离子交换分离柱,KOH溶液为淋洗液作梯度淋洗,硝酸盐、亚硝酸盐和多聚磷酸盐的线性相关系数在0.998 1~0.999 8之间,回收率为79.2%~93.6%,相对标准偏差小于8.2%。经处理后的样品中,焦磷酸盐、三聚磷酸盐和三偏磷酸盐的总量在14 h内保持稳定。利用该法对东海地区典型海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐进行了测定,结果显示不同品种的海产品中硝酸盐、亚硝酸盐和多聚磷酸盐含量分布有较大差异,除其中一份虾制品中多聚磷酸盐含量超过5 g/kg外,其余均符合国家限量标准。

A method for determining nitrate, nitrite and polyphosphates including phosphate, pyrophosphate, triphosphate and trimetaphosphate in seafood using ion chromatography(IC) was proposed. The stability and contents of these compounds in seafood were also investigated. The separation was achieved on hydrophilic anion exchange column through gradient elution using potassium hydroxide as the elutant. The determination coefficients of the developed linear equations for these analytes were in the range of 0.998 1–0.999 8, and the recoveries of spiked samples ranged from 79.2% to 93.6%with RSD less than 8.2%. The total content of pyrophosphate, triphosphate and trimetaphosphate was stable within 14 h. This method has been successfully applied to the determination of pyrophosphate, triphosphate and trimetaphosphate in different kinds of seafood products from the East China Sea. The results showed that a wide variation in the contents of nitrate, nitrite and polyphosphates existed among different seafood products, and all residual contents met the national maximum allowable residue levels except that polyphosphates in one sample were more than 5 g/kg.