淡水鱼中无机砷的液相色谱-原子荧光光谱测定法

目的建立液相色谱-原子荧光光谱法测定淡水鱼中无机砷[AS(Ⅲ),AS(Ⅴ)]的方法。方法准确称取鱼肉1.0 g,用0.15 mol/L硝酸于60℃超声提取40 min,加正己烷除去杂质后经0.45μm有机滤膜过滤及C18小柱净化。采用Hamilton PRP X-100阴离子交换柱(150 mm×4.1 mm,10μm)分离,磷酸氢二钠和磷酸二氢钾(pH=4.0)为流动相等梯度洗脱,流速1.3 ml/min,用原子荧光检测。保留时间定性,外标法定量。结果2种砷形态线性关系良好(r>0.999),方法检出限AS(Ⅲ)为0.017 mg/kg,AS(Ⅴ)为0.050 mg/kg。平均回收率为85.4%~103.8%,精密度为1.1%~3.4%。结论本方法操作简便、结果准确、精密度高,适用于同时检测淡水鱼中2种形态的无机砷AS(Ⅲ)和AS(Ⅴ)。

Determination of inorganic arsenic in freshwater fish by liquid chromatography-atomic fluorescence spectrometry

[Objective]To establish a method for the determination of inorganic arsenic [AS(Ⅲ),AS(Ⅴ)] in freshwater fish by liquid chromatography-atomic fluorescence spectrometry.[Methods]1.0 g of fish meat was accurately weighed and extracted with0.15 mol/L nitric acid at 60 ℃ for 40 min. After adding hexane,the mixture was filtered through 0.45μm organic membrane and purified by C18 cartridge,then separated by Hamilton PRP X-100 anion exchange column(150 mm ×4.1 mm,10 μm). The disodium hydrogen phosphate and potassium dihydrogen phosphate(pH=4.0) were used as mobile phase in flow-equal gradient elution at a flow rate of 1.3 ml/min,and atomic fluorescence detection was performed. The retention time was used for qualitative detection and external standard method was used for quantification.[Results]The linear relationships of the two arsenic species were good(r>0.999). The detection limit of AS(Ⅲ) and AS(Ⅴ) was 0.017 mg/kg and 0.050 mg/kg respectively.The average recovery was85.4%-103.8%,and the precision was 1.1%-3.4%.[Conclusion]This method is simple and accurate,with high precision. It is suitable for simultaneous detection of two forms of inorganic arsenic AS(Ⅲ) and AS(Ⅴ) in freshwater fish.