高效液相色谱-电感耦合等离子体质谱联用技术测定饲料中7种砷形态化合物

Derermination of seven arsenic species in feed by HPLC-ICP-MS

为建立高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)法测定饲料中亚砷酸盐As(Ⅲ)、砷酸盐As(V)、一甲基砷(MMA)、二甲基砷(DMA)、对氨基苯胂酸(p-ASA)、硝羟苯胂酸(ROX)和卡巴胂(Carbarsone)7种砷形态化合物。本实验采用甲醇-水溶液(1∶1,V/V)作为提取剂超声水浴提取样品,以Dionex Ion Pac AS7作为分析柱,(NH4)2CO3溶液作为流动相梯度洗脱,对饲料中的砷形态化合物进行分析测定。结果表明:7种砷形态化合物线性范围为1~300μg/L,线性相关系数(R2)均大于0.999,检出限为0.2~0.6μg/L,方法的重现性(RSD)均小于5%,加标回收率为82.3%~104.7%。通过对实际样品的检测,饲料中砷形态主要以含量极低的亚砷酸盐As(III)、砷酸盐As(V)和二甲基砷(DMA)存在,生猪饲料中存在添加高含量对氨基苯胂酸(p-ASA)的情况。

A s(Ⅲ),A s(Ⅴ),MMA,DMA,p-ASA,ROX and Carbarsone in feed were determined by high performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS).Ultrasonic water bath was used to pretreat the samples with methanol-water(1:1,F/V)as extraction agent.Dionex Ion Pac A S7 anion exchange column and(NH4)2CO3 solution was used to analyze arsenic species in feed.The results showed that the linear ranges for seven arsenic species were all between 1 and 300μg/L with linear coefficients more than 0.999,and the detection limits were between 0.2 and 0.6μg/L.The relatives standard deviations(RSD s)for the determination of seven species were less than 5%and the recoveries were between 82.3%and 104.7%.Through the analysis of actual samples,the low-level As(Ⅲ),As(Ⅴ)and DMA were checked out in feed,and a high content of p-ASA was also checked in swine feed.