HPLC-ICP-MS测定中药中砷的形态

Determination of arsenic speciation in traditional chinese medicine using HPLCICP-MS

报道了高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术测定中药中砷的形态,采用阴离子交换柱,以0.2 mmol/L EDTA和2 mmol/LNaH2PO4的溶液为流动相,pH 6.0,流速为1.0 mL/min,成功分离了亚砷酸(AsⅢ)、砷酸(AsⅤ)、甲基砷(MMA)和二甲基砷(DMA)。检出限分别为0.67μg/L(AsⅢ),0.85μg/L(DMA),0.43μg/L(MMA),0.70μg/L(AsⅤ)。中药样品经过(1+1)甲醇和水的溶液超声提取,离心、过滤、氮气吹干甲醇,超纯水定容。样品加标平均萃取回收率分别为:92.8%(AsⅢ),108%(DMA),104%(MMA),101%(AsⅤ),相对标准偏差(RSD,n=7)均小于10%。

Separation of 4 arsenic species as arsenite （As Ⅲ ）, dimethylaronic acid （DMA）, monomethylarsonic acid （MMA）, and arsenate （AsV） on a single column was achieved by anion-exchange high performance liquid chromatography （HPLC） and element-selective detections were provided by inductively coupled plasma spectrometry （ICP- MS）. The optimized mobile phase composition was 2.0 mmol/L sodium dihydrogen phosphate, 0.2 mmol/L EDTA at pH 6.0. The limits of detection （LOD） were 0.67, 0.85, 0.43, 0.70μg/L respectively. The influence of mobile phase pH and its composition on the separation efficiency was studied. Samples of traditional Chinese medicine （TCM） were extracted by sonication three times with methanol-water mixture （1 to 1, v/v）. The combined extracts were then centrifuged and filtered before being dried with nitrogen. Average spiked recoveries for arsenite, DMA, MMA and arsenate were 92.8, 108, 104, 101% respectively, for TCM samples. Relative standard deviations （ n = 7） were below 10%.