离子色谱-等离子体质谱联用测定热泉水样的砷形态

Simultaneous determination of arsenic species in hot spring water using IC-ICP-MS

利用阴离子色谱与六极碰撞等离子体质谱联用的方法,在线同时测定水样的4种砷形态(As(Ⅴ),As(Ⅲ),MMA,DMA),并用于实际样品-热泉水中砷形态的测定。使用K2HPO4-KH2PO4为淋洗液等度淋洗,用Hamilton PRP-X100阴离子色谱柱分离,4种砷形态在7 min之内完全分离。调节淋洗液中K2HPO4与KH2PO4的比例可以优化峰的分离。地下水(含热泉水)基质、样品及淋洗液中的Cl-对砷形态的分离测定没有影响,淋洗液中的盐份在样品锥和截取锥上的积累对测定的影响很小。检出限分别为As(Ⅴ)0.23μg/L,As(Ⅲ)0.30μg/L,MMA 0.26μg/L,DMA 0.54μg/L。

The simultaneous determination of four arsenic species （As（ Ⅴ ）, As（ Ⅲ ）, MMA and DMA） was carried out by coupling an anion exchange column to a hexapole collision inductively coupled plasma mass spectrometer. This method was successfully applied to the determination of arsenic species in hot spring water in Yurman province, China. Using an isocratic elution （eluant K2 HPO4-KH2 PO4 ）, the four arsenic species were separated on a Hamilton PRPX100 anion exchange column in 7 rain. The separation of the peaks of arsenic species could be optimized through adjusting the K2HPO4-KH2PO4 ratio of the eluant. The analysis was not interfered by ground water （including hot spring water） matrix as well as Cl^- in both samples and eluant, The effect of the precipitation of salt on the cones of the ICPMS on the stability of this method can be neglected. The detection limits were 0.23 μg/L for As（ Ⅴ ）, 0.30 μg/L for As（ Ⅲ ）, 0.26 μg/L for MMA and 0.45 μg/L for DMA respectively.