离子色谱法检测水产品中的硝酸盐与亚硝酸盐

Determination of Nitrate and Nitrite in Seafood by Ion Chromatography

利用免试剂离子色谱法建立测定水产品中硝酸盐和亚硝酸盐的检测方法。样品经搅碎,超声提取,75～80℃水浴加热,离心,减压过滤,再经OnGuardⅡRP柱除去微量的蛋白质和脂肪,稀释,0.22μm水系膜过滤器过滤后,进离子色谱系统。经KOH等浓度淋洗(KOH浓度为15 mmol/L,抑制电流为38 mA,流速为1 mL/min),IonPac AG11-HC(4 mm×50 mm)保护柱,IonPac AS11-HC(4 mm×250 mm)分离柱分离后,用抑制型电导检测器检测。本方法的相关性好,NO3-的相关系数为0.99914,NO2-的相关系数为0.99952,NO3-的检出限为0.0277 mg/kg,NO2-的检出限为0.0186 mg/kg。鲈鱼中这两种离子的加标回收率在60%～81%之间,RSD在5%内。本方法方便、快捷、安全,操作简便,对多种样品适应性好。

In this study,A reliable method was established to detect the concentration of nitrate and nitrite in seafood by reagent-free ion chromatography.Seafood samples were homogenized and ultrasonic extracted with the 75～80 ℃ water bath,and then centrifuged and vacuum filtrated.The small portion of protein and fat were removed by OnGuardⅡ RP column.Before injection to the ion chromatography system,the filtrate was multiple diluted and pushed through 0.22 μm membrane.Potassium hydroxide solution was used as the isocratic effluent,and separation was carried on an IonPacAS11-HC（4 mm×250 mm） analysis column with an IonPacAG11-HC（4 mm×50 mm） guard column,and suppressed conductivity detector was used.This method showed a good linearity,the correlation coefficient was 0.999.The detection limit of NO3-was 0.0277 mg/kg; the detection limit of NO2-was 0.0186mg/kg.The recoveries of the spiked fresh weever samples ranged from 60% to 81% and RSD was less than 5%.The results showed that the method was convenient,fast,safe and reliable.