Rapid determination of 15 metallic elements in 2 kinds of coix seeds by inductively coupled plasma-mass spectrometry after closed-vessel microwave digestion

摘要

This paper presents an optimal method and verification process for measuring contents of 15 metal elements (boron, magnesium, aluminum, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, tin, antimony, and lead) in two kinds of coix seeds with microwave digestion-inductively coupled plasma-mass spectrometry. The results showed that microwave digestion-inductively coupled plasma-mass spectrometry was a simple and convenient method, which can accurately determine contents of 15 metal elements in coix seed, with detection limit ranging within 0.0016-7.02mg/L, and recovery rate varying within 96.00-104.87%. National primary standard substance-green onions (GBW10049 GSB-27) were adopted to verify accuracy and precision of such method. The two tested coix seeds (Xingren smaller coix seed and Yunnan bigger coix seed) both contain Mn, Zn, Ca, Mg, Fe in high content, wherein the Xingren smaller coix seed is richer in Al, Cr, Ni, Cu, and Mg as compared to Yunnan bigger coix seed. Contents of heavy metals such as Ni, Cr, Pb, Cd, Sn, and Sb are in line with GB 2762-2012 of limits of contaminants in foods. This method which can simultaneously determining 15 essential and nonessential elements in coix seed enjoys an acceptable analytical performance and is applicable for routine laboratory testing.