液相色谱-氢化物发生/原子荧光法测定啤酒中砷的形态

Determination of Arsenic Species in Beer Samples by Liquid Chromatography-Hydride Generation Atomic Fluorescence Spectrometry

采用液相色谱-氢化物发生/原子荧光(LC-HG/AFS)联用技术测定了啤酒中砷的形态。优化了氢化物发生的实验条件,当以10%的盐酸为载流,3.5%的KBH4为还原剂,流量为500mL/min的氩气作为载气时,取得了较好的信号强度;以20mmol/LKH2PO4-K2HPO4(pH=6.0,流速1mL/min)为流动相,在Hamilton PRP-X100阴离子柱中,成功分离了亚砷酸(As(Ⅲ))、二甲基胂酸钠(DMA)、一甲基砷酸二钠(MMA)和砷酸As(Ⅴ)四种砷的化合物,洗脱时间依次为2.80min、3.90min 5.38min和12.01min,检测限分别是0.8μg/L、2.1μg/L、0.8μg/L和1.6μg/L。4种砷的化合物在0～200μg/L范围线性良好,其加标回收率范围在91.4%～104.4%之间。该法具有简便、快速、灵敏的特点。

Based on the hydride generation—atomic fluorescence spectrometry detection and liquid chromatography separation,an analytical method for arsenic speciation in beers was developed.Four arsenic species,i.e.,arsenite As（Ⅲ）, dimethylarsinic acid（DMA）,monomethylarsonic acid（MMA） and arsenate As（Ⅴ） were separated by anion-exchange chromatography with isocratic elution using 20 mmol/L KH2PO4/K2HPO4 as the mobile phase with the flow rate of 1 mL/min.The elution time were 2.80,3.90,5.42 and 12.01 min for As（Ⅲ）,DMA,MMA and As（Ⅴ）,respectively.Potassium borohydride（3.5%,m/V） and hydrochloric acid（10%,m/V） were used as the reduction agents and the argon with a flow rate of 500 mL/min was used as the carrier gas to deliver the volatiled species.The detection limits of the As（Ⅲ）,DMA,MMA and As（Ⅴ） were 0.8 μg/L,1.6 μg/L,0.8 μg/L,2.1 μg/L,respectively.The linear response for the four arsenic species were obtained in the range of the 0~200 μg/L,and the recovery values were between 91.4%~104.4%.The developed method is simple,rapid and sensitive,and suitable for arsenic speication in beer sample.