微波萃取-原子荧光光谱法测定稻米中砷化学形态

采用微波萃取、高效液相色谱-氢化物发生-原子荧光光谱法联用技术建立了稻米中了三价砷As(Ⅲ)、五价砷As(V)、一甲基砷酸(MMA)、二甲基砷酸(DMA)等4种形态砷的分析方法。结果表明,稻米中4种形态砷的加标回收率为80%～110%,批内及批间相对标准偏差为0.3%～4.8%,方法检出限为1.6~4.0μg/kg。将该方法应用于实际样品的测定,分析结果显示,稻米样品中含有一定量的三价砷As(Ⅲ)和少量的二甲基砷酸(DMA),其形态之和已接近我国国标中关于稻米产品中砷限量标准的规定。

Speciation analysis of Arsenic in rice by microwave extraction-atomic fluorescence spectrometry

A method was developed for simultaneously determination of four arsenic speciation including As(Ⅲ),As(V),monomethylarsinic acid(MMA) and dimethylarsinic acid(DMA) in rice.Arsenic speciation in samples were extracted with microwave extraction,and then detected by high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry(HPLC-HG-AFS).The recoveries of four arsenic speciation were 80%～110% with RSD of 0.3%～4.8%,and detection limits were 1.6～4.0 μg/kg.The method was then applied to detect of rice samples randomly purchased from markets.The analytical results showed that the main arsenic speciation were As(Ⅲ) and low DMA in rice.The amount of arsenic concentrations was close to rice limit of China National Standards.