微波消解-液相色谱-原子荧光光谱联用(LC-AFS)法测定稻米样品中砷形态

建立了稻米中4种砷元素形态的液相色谱-原子荧光光谱联用法(LC-AFS),样品用0.15mol/L的硝酸溶液微波提取50min,提取液经离心分离后,采用Hamilton PRP-X100色谱柱,45mmol/L KH2PO4-5mmol/L Na2HPO4缓冲液为流动相,砷形态4个组分能够在7min内达到基线分离,且无需调pH。优化了氢化物发生条件,使用了更低浓度的载流和还原剂。方法学实验结果表明,各组分在2~10ng/mL范围内线性关系良好,相关系数为0.9988~0.9998,各组分的检出限分别为0.29 ng/mL、0.47 ng/mL、0.62 ng/mL和1.16 ng/mL；各组分峰面积的相对标准偏差均低于3.11%；加标回收率为85.3%～112.8%；对稻米标准物质的分析测定结果表明该方法定值准确。最后,与GB 5009.11-2014中使用的提取及测量条件进行对比,表明该方具备法快速、环保、高效的特点。

Speciation Analysis of Arsenic in Rice Samples by Microwave Extraction Coupled with HighPerformance Liquid Chromatography-Atomic Fluorescence Spectrometry

A method of high performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) was established for the determination of four arsenic speciation in rice. The sample was extracted by microwave with 0.15mol/L nitric acid solution for 50 min. After centrifugation, the extraction were separated by Hamilton PRP-X100 column using 45mmol/L KH2PO4-5mmol/L Na2HPO4 buffer as the mobile phase, and the four components of arsenic form could be separated from the baseline in 7min. And the pH value of mobile phase was no need to adjust. The conditions of hydride generation were optimized, and the lower concentration of carrier current and reducing agent were used. The evaluation of method was researched. Good linear ranges of the four arsenic forms were obtained ranging from 2 ng/mL to 10 ng/mL, and the correlation coefficients were between 0.9988 and 0.9998. The limits of detection for the four compounds were 0.29, 0.47, 0.62 and 1.16 ng/mL, respectively. The relative standard deviations (RSD) of peak area for the four arsenic forms were less than 3.11%. The spiked recoveries of the four compounds were in the range of 85.3%~112.8%. The rice standard material was analyzed, and the accurate test results were obversed. Finally, the comparison with extraction and measuring conditions used in GB 5009.11-2014 showed that the method were fast,environmental and high efficiency.