液相色谱-原子荧光光谱法测定沉积物中4种砷形态

Determination of Four Arsenic Forms in Sediments by Liquid Chromatography Atomic Fluorescence Spectroscopy

基于液相色谱–原子荧光光谱联用技术,建立了同时快速分析沉积物中AS(Ⅲ)、DMA、MMA及AS(Ⅴ)4种砷不同形态的方法。对提取剂进行优化,结果表明,1.0 mol/L磷酸和0.5 mol/L抗坏血酸10 mL提取砷不同形态效果较好;对提取方法进行优化,结果表明,80℃微波提取30 min提取率较高;对比提取液净化前后样品回收率发现,C_(18)固相柱可以避免目标化合物吸附损失;4种不同形态砷在一定线性范围内相关性良好,相关系数均大于0.999,方法检出限为0.018~0.083 mg/kg;样品加标回收率为70.5%~95.9%,相对标准偏差(RSD,n=6)为3.2%~9.0%;沉积物样品中以无机砷为主,AS(Ⅴ)的含量高于AS(Ⅲ)含量;该方法检出限、精密度和准确度均满足分析要求,为保障水环境质量安全提供了技术支撑。

A method for simultaneous and rapid analysis of four different forms of arsenic in sediments,namely AS(III),DMA,MMA,and AS(V),was established based on liquid chromatography atomic fluorescence spectroscopy.The optimization of the extraction agent showed that 1.0 mol/L phosphoric acid and 0.5 mol/L ascorbic acid 10 mL were effective in extracting different forms of arsenic.The extraction method was optimized,and the results showed that the extraction rate was higher after 30 min of microwave extraction at 80℃.Comparing the recovery rates of samples before and after purification with the extraction solution,it was found that the C_(18) solid-phase column can avoid the adsorption loss of the target compound.Four different forms of arsenic had good correlation within a certain linear range,with correlation coefficients greater than 0.999.The detection limit of the method was from 0.018 to 0.083 mg/kg.The recovery rate of sample spiking was from 70.5%to 95.9%,and the relative standard deviation(RSD,n=6)was from 3.2%to 9.0%.The actual sediment samples were mainly composed of inorganic arsenic,and the content of AS(Ⅴ)was higher than that of AS(Ⅲ).The detection limit,precision,and accuracy of this method all meeted the analysis requirements,which could provide technical support for ensuring water environment quality and safety.