试样用硝酸加压消解(测总砷),或用盐酸(1+1)溶液在60 ℃浸取(测无机砷)。以硫脲溶液作为预还原剂,以硼氢化钾溶液作为还原剂,利用原子荧光光谱法测定中药材中砷的含量。分析中采用载气及屏蔽气的流量依次为400 mL·min-1及900 mL·min-1。砷(Ⅲ)的荧光强度与其质量浓度在80.0 μg·L-1以内呈线性关系,方法的检出限(3s/k)为31 ng·L-1。应用此法对中药材样品进行分析,样品中总砷测定值在139~372 ng·g-1之间,加标回收率在89.0%~93.3%之间;无机砷测定值在41~103 ng·g-1之间,加标回收率在86.0%~92.0%之间。

AFS was applied to the determination of arsenic in Chinese traditional medicines. The sample was digested with HNO3 under pressure (for total As), and extracted with HCl (1+1) at 60 ℃ (for inorganic As). Thiourea solution was added to the sample solution as pre-reductant and KBH4 solution as reductant. Flow-rates of 400 mL·min-1 for carrier gas and 900 mL·min-1 for shielding gas were taken in the analysis. Linear relationship between values of fluorescence intensity and mass concentration of As(Ⅲ) found was in the range within 80.0 μg·L-1, with detection limit (3s/k) of 31 ng·L-1. The proposed method was applied to the analysis of samples of Chinese traditional medicines. Values of total As found were in the range of 139-372 ng·g-1 and of inorganic As in the range of 41-103 ng·g-1. Values of recovery found were in the ranges of 89.0%-93.3% for total As and 86.0%-92.0% for inorganic As.