高效液相色谱-动态反应池-电感耦合等离子体质谱法测定海产品中砷形态

Determination of arsenic species in seafood samples by HPLC-DRC-ICP-MS

目的建立HPLC-DRC-ICP-MS法准确测定海产品中砷甜菜碱(As B)、二甲基砷(DMA)、一甲基砷(MMA)和无机砷[As(Ⅲ)和As(V)]等砷形态的含量。方法海产品经1%硝酸溶液提取和HLB固相萃取柱净化后,经HPLC-DRC-ICP-MS法测定海产品中的砷形态。结果以Dionex Ion Pak AS19(4 mm×250 mm,10μm)柱为色谱分离柱,以10 mmol/L无水乙酸钠/3 mmol/L硝酸钾/10 mmol/L磷酸二氢钠/0.2 mmol/L乙二胺四乙酸二钠缓冲液(p H=10)为流动相,采用DRC(反应气为O2)模式下,该方法对砷形态的分离效果较好,且能有效地消除氯氩(Ar Cl+)对质谱信号的干扰,确保了测定方法的准确性。在最优条件下,海产品中As B、DMA、MMA和无机砷[As(Ⅲ)和As(V)]的方法检出限为0.003 7 mg/kg~0.006 7 mg/kg,加标回收率为87.5%~109.0%,相对标准偏差为1.4%~8.8%。结论该方法灵敏度高,准确度高和精密度好,适用于海产品中不同形态As的检测。

Objective To establish an accurate method for the determination of arsenobetaine( As B),dimethyl arsenic( DMA),monomethylated arsenic( MMA),inorganic arsenic [As( Ⅲ) and As( V) ]in seafood by HPLC-DRC-ICP-MS method. Methods Seafood samples were firstly extracted with 1% nitric acid,and then purified with HLB solid-phase extraction. Afterwards,HPLC-DRC-ICP-MS method was employed to determine the As species in seafood. Results Satisfactory chromatographic separation could be obtained when Dionex Ion Pak AS19( 4 mm × 250 mm,10 μm) was used as chromatographic column,and 10 mmol/L sodium acetate/3 mmol/L KNO3/10 mmol/L Na H2 PO4/0. 2 mmol/L EDTA buffer( p H =10) was used as mobile phase. Meanwhile,based on DRC mode( O2 as the reaction gas),the MS interferences resulted from Ar Cl+could be eliminated. Moreover,due to avoiding the entry of Ar Cl+into MS instrument under the DRC mode,not only matrix interference could be reduced,but also sensitivity and stability of the method could be improved. Under the optimal conditions,the detection limits of As B,DMA,MMA,inorganic arsenic [As( Ⅲ) and As( V) ]in seafood samples were within0. 0037 mg/kg-0. 0067 mg/kg,while the spiking recoveries and the relative standard deviations were within 87. 5%-109. 0%and 1. 4%-8. 8%,respectively. Conclusion The developed method is sensitive,accurate,and precise,and is suitable for the determination of arsenic species in seafood samples.