Comparison of ICP-MS and Two Other Analytical Methods for Determination of Selenium Content in Cordyceps Militaris

Samples were digested by microwave digestion. The selenium content in selenium enriched Cordyceps militaris was determined by ICP-MS method, HPLC/fluorometric method, and 3,3-diaminobenzidine method separately. And the detection conditions, the lowest detection limit and the relative standard deviation (RSD) of the three determination methods were compared. The detection conditions of the three methods for the detection of selenium content in selenium enriched Cordyceps militaris were established. It was showed that the lowest detection limit of ICP-MS method, HPLC/fluorometric method, and 3,3-diaminobenzidine method was 0.260 7, 0.182 1 and 10.485 9 mu g . L-1 respectively, and this means that the lowest detection limit of ICP-MS method was the lowest and that of 3,3-diaminobenzidine method was the highest. For the same sample the relative standard deviation (RSD) of ICP-MS method was the lowest and the RSD of 3,3-diaminobenzidine method was the highest. It was recommended that selenium content is determined by ICP-MS and HPLC/fluorometric method when the selenium in the sample is very low and by 3,3-diaminobenzidine method when the content is rather high.