微波消解-石墨炉原子吸收分光光度法测定防风中的砷和铅

Determination of arsenic and lead in Saposhnikovia divaricata by microwave digestion-graphite furnace atomic absorption spectrometry

目的测定中药防风中砷和铅的含量。方法将防风干燥后粉碎过200目筛备用。取约0.5g样品加入5 m L硝酸浸泡过夜。次日补加2 m L硝酸、1 m L双氧水后放入微波消解仪内消解5 min,将剩余溶液加热至约1 m L后用二次水定容于25 m L容量瓶中用作测试溶液,同法作一空白对照组。采用石墨炉原子吸收光谱法测定其中重金属砷和铅的含量。结果微波消解方式采用阶梯升温(100℃,150℃,180℃),升温速率为8℃·min^(-1)。在此条件下测得铅的检出限分别为0.201 ng/m L,相对标准偏差为1.1%~2.1%(n=10),回收率为90.2%~94.3%;砷的检出限0.0138 ng/m L,相对标准偏差为1.5%~1.9%(n=10),回收率为95.2%~103.0%。结论本方法具有简便快捷,精密度和准确度较好的特点,适用于防风中重金属铅和砷的痕量检测。

Objective To ta. Methods Saposhniko determine the content of arsenic and lead in Saposhnikovia divaricavia divaricata was crushed and filtered through 200 mesh filter. About 0. 5 g sample was soaked in 5 mL nitric acid overnight. The next day 2 mL nitric acid and 1 mL hydrogen peroxide were added and heated for 5 min by microwave digestion, the remaining solution was heated to about 1 mL and transferred to 25 mL volumetric flask as a test solution, with the same method of blank control group. Content of arsenic and lead were determined by graphite furnace atomic absorption （GFAAS）. Results Step heating method was adopted （100 ℃, 150 ℃, 180℃ ）, the heating rate was 8 ℃ . min-1, the detection limits were 0. 201 ng/mL for lead and 0. 0138 ng/mL for arsenic respectively. The relative standard deviations for lead were between 1.1% and 2. 1% and for arsenic between 1.5% and 1.9% ; the recoveries of lead were between 90. 2% and 94. 3% and for arsenic were between 95.2% and 103.0%. Conclusion The method is convenient and rapid with good precision and accuracy, which is fit for the determination of arsenic and lead in Saposhnikovia divaricata.