[Major, minor and trace-elemental contents analysis in northeast soybeans by ICP-AES]

Major, minor and trace elemental contents in northeast China soybeans were determined by using inductively coupled plasma atomic emission spectrometry (ICP-AES). Three different sample digestion methods including two wet digestions, HNO3-HClO4 and HNO3-H2SO4 and a dry ash method were compared. Owing to the high oil content in soybeans, long time is needed and access acid should be added with mixed acid digestion methods, which may result in higher sample blank. Therefore, the dry ask method would be more proper for the pre-treatment of soybean samples. Potassium and phosphorus are major elements in soybeans, so the effect of potassium and phosphorus on the other elements was investigated. Results showed that the potassium and phosphorus did not affect the determination of other trace elements. There are not significant differences in trace elemental contents for the eleven northeast China soybeans.