氢化物发生-原子荧光光谱法测定大蒜中砷和硒

HG-AFS Determination of Arsenic and Selenium in Garlic

采用氢化物发生-原子荧光光谱法测定大蒜中砷和硒。样品经硝酸和高氯酸消解,在盐酸(5+95)溶液中,加入溶于50g·L^(-1)氢氧化钠溶液的20g·L^(-1)硼氢化钾溶液,使其与溶液中砷及硒离子反应生成氢化物。分析中采用载气流量依次为800mL·min^(-1),600mL·min^(-1),屏蔽气的流量均为1000mL·min^(-1)。试样溶液中加入硫脲-抗坏血酸混合溶液作为还原剂。于仪器中引入试样溶液0.5mL,按选定的工作条件操作。砷及硒的质量浓度分别在0.04～0.40,1.00～10.0μg·L^(-1)范围内与其荧光强度呈线性关系,方法的检出限(3s/k)砷为0.017μg·L^(-1),硒为0.314μg·L^(-1)。分别加入两元素的标准溶液作回收试验,测得砷和硒的回收率分别在95.3%～104.4%和94.7%～105.2%之间。

HG-AFS was applied to the determination of arsenic and selenium in garlic.Hydrides of As and Se ions were generated from HCl（5＋95） solution by reacting with 20 g·L^（-1） KBH_4 solution（dissolved in 50 g·L^（-1） NaOH solution）.Flow-rates of carrier gas of 800 mL·min^（-1） for As and 600 mL·min^（-1） for Se,and flow-rate of shielding gas of 1 000 mL·min^（-1） were taken in the analysis.Mixed solution of thiourea and ascorbic acid was added to the sample solution as reductant.An aliquot of 0.5 mL of sample solution was introduced and operated under the prescribed working condition of the instrument.Linear relationships between the fluorescence intensity and mass concentration of As and Se were found in the ranges of 0.04-0.40 and 1.00-10.0μg·L^（-1）,with detection limits （3s/k） of 0.017μg·L^（-1） and 0.314μg·L^（-1） respectively.Recovery was tested by addition of standard solutions, giving values of recovery in the ranges of 95.3%-104.4%for As and 94.7%-105.2%for Se.