高效液相色谱-电感耦合等离子体串联质谱法同时测定土壤中的阿散酸、洛克沙胂及其降解产物

Simultaneous Determination of p-Arsanilic Acid,Roxarsone and Their Degradation Products in Soils by HPLC-ICP-MS/MS

建立了高效液相色谱-电感耦合等离子体串联质谱(HPLC-ICP-MS/MS)同时测定土壤中阿散酸(p-ASA)、洛克沙胂(ROX)及其降解产物无机砷(i-As)(亚砷酸(As(Ⅲ))和砷酸(As(Ⅴ)))、一甲基砷(MMA)和二甲基砷(DMA)等5种砷形态的分析方法。以0.1 mol/L NaH 2PO4-0.1 mol/L H 3PO 4(体积比9∶1)为提取剂,液固比为50 mL/g,样品经微波辅助提取(80℃,30 min)后,采用Hamilton PRP-X100阴离子交换柱(250 mm×4.1 mm,10μm),以60 mmol/L(NH 4)2HPO 4-5%甲醇(pH 6.0)和水为流动相进行梯度洗脱,在15 min内实现了5种砷形态的良好分离。在优化条件下,各砷形态在0~500μg/L范围内线性良好(r^2≥0.9991),检出限为0.043~0.080μg/kg(以As计),相对标准偏差为1.7%~3.8%。将该方法用于分析3种土壤样品,各砷形态的加标回收率为71.6%~106%。该方法简单、快速、准确、可靠,适用于土壤中阿散酸、洛克沙胂和常规砷形态的检测。

A high performance liquid chromatography-inductively coupled plasma-tandem mass spectrometry(HPLC-ICP-MS/MS)was developed for the simultaneous determination of six arsenic species,i.e.p-arsanilic acid(p-ASA),roxarsone(ROX)and their degradation products arsenite(As(Ⅲ))and arsenate(As(Ⅴ))(inorganic arsenic),monomethylated arsenic(MMA)and dimethylated arsenic(DMA)in soils.The soil samples were extracted with 0.1 mol/L NaH 2PO4-0.1 mol/L H 3PO4(9∶1,by volume)as extraction solvent at a liquid-to-solid ratio of 50 mL/g,by microwave-assisted extraction at 80℃for 30 min.Five arsenic species in the extracts were well separated within 15 min on a Hamilton PRP-X100 anion exchange column(250 mm×4.1 mm,10μm)using 60 mmol/L(NH 4)2HPO4 containing 5%methanol(pH 6.0)and water as mobile phases by gradient elution.Under the optimized conditions,there were good linear relationships for the analytes in the concentration range of 0-500μg/L with their correlation coefficients(r 2)not less than 0.9991.The limits of detection were 0.043-0.080μg/kg for the analytes,and the relative standard deviations ranged from 1.7%to 3.8%.The method was applied in the analysis of three soil samples,and recoveries for the analytes were in the ranges of 71.6%-106%.The developed method is simple,rapid,accurate and reliable,and is suitable for the determination of arsenic species in soils.