微波消解-双道原子荧光法测定天麻等5种药材中的硒和锗

Microwave digestion-dual channel atomic fluorescence spectrometry for determination of selenium and germanium in Chinese herbs

目的：用氢化物发生-原子荧光光谱法同时测定天麻、首乌、当归、沙参、黄连5种中药材中的硒和锗。方法：样品经硝酸-过氧化氢微波消解后,在磷酸介质中,以硫脲为预还原剂,采用双道原子荧光法进行中药材中硒和锗的测定。结果：在选定的最佳条件下,仪器对硒与锗的检出限分别为0.25 ng·mL-1和1.46 ng·mL-1,RSD分别为1.9%和2.9%,回收率分别为91.7%~97.2%和89.5~95.7%,RSD均小于5%。线性范围均为0~300 ng·mL-1。干扰离子Cr3＋、Cu2＋、Zn2＋、Co2＋对硒的影响最大,Pb2＋、Ni2＋对锗的干扰最大,因待测液中浓度并未达到干扰硒锗测定的程度,故不予考虑。结论：5种药材中硒的含量范围为533.1~1773 ng·g-1,其顺序为野生天麻〉黄连〉首乌〉当归〉沙参,沙参最低;锗的含量范围是253.9~842.5 ng·g-1,其顺序为野生天麻〉沙参〉当归〉首乌〉黄连,黄连最低。野生天麻样品中两元素的含量均高于其他栽培样品。

Objective： To simultaneously determine selenium and germanium in Gastrodiae Rhizoma,Polygoni Multiflori Radix,Angelicae Sinensis Radix,Adenophorae Radix and Coptidis Rhizoma by hydride generation-atomic fluorescence spectrometry. Methods： After samples were digested by nitric acid and hydrogen peroxide,selenium and germanium in five Chinese herbs were simultaneously determined in 5% H3PO4 by dual channel- atomic fluorescence spectrometry with thiourea as pre- reductant. Results： Under optimal conditions,the detection limits of selenium and germanium were 0. 25 ng· mL- 1and 1. 46 ng·mL- 1; RSDs were1. 9% and 2. 9%,respectively. The recoveries of Se and Ge were 91. 7%- 97. 2% and 89. 5%- 95. 7%,respectively,with RSD less than 5%. The interferences from Cr3 ＋,Cu2 ＋,Pb2 ＋,Ni2 ＋,Zn2 ＋,Co2 ＋were investigated in detail. It showed that Cr3 ＋,Cu2 ＋,Zn2 ＋and Co2 ＋had serious influence on Se and Pb2 ＋,Ni2 ＋affected Ge determination. Because the concentrations of the six selected ions did not reach the interference level,the influences of whidn can be ignored in this study. Conclusion： It was found that the contents of Se in the five samples were in the range of 533. 1- 1773 ng·g- 1,in the order of wild Gastrodiae Rhizoma 〉Coptidis Rhizoma 〉Polygoni Multiflori Radix 〉Angelicae Sinensis Radix 〉 Adenophorae Radix and the Ge range was 253. 9- 842. 5 ng·g- 1,following the order of wide Gastrodiae Rhizoma 〉 Adenophorae Radix 〉 Angelicae Sinensis Radix 〉 Polygoni Multiflori Radix 〉 Coptidis Rhizoma. The contents of both elements were higher in wild Gastrodiae Rhizoma than in the cultivated samples.