Determination of Multiple Mineral Elements in Chia Seeds by Microwave Digestion Combined with ICP-OES and ICP-MS

To establish the determination method of 16 mineral elements(K,Na,Ca,Mg,Fe,Mn,Zn,Cu,P,B,Pb,Cd,As,Cr,Al,Ni),the samples were digested by microwave. The contents of K,Na,Ca,Mg,Fe,Mn,Zn,Cu,P and B were determined by ICP-OES and the contents of Pb,Cd,As,Cr,Al and Ni were determined by ICP-MS. The results showed that the detection limit of ICP-OES was 0.00850~0.10200 mg/L and the limit of quantitation was 0.0283~0.3400 mg/L. The detection limit of ICP-MS was 0.00471~0.11330 mg/L and the limit of quantitation was 0.0157~0.3777 mg/L. The linear correlation coefficients were r>0.999,the recovery rate was more than 90.4%~99.8%,and the relative standard deviation was 0~4.1%. The accuracy of the method was evaluated by the national standard materials rice(GBW10045(GSB-1)and wheat(GBW10011(GSB-2)and showed that it was within the standard value range. The results showed that there were abundant P,K,Ca and Mg in Chia seeds,among which the content of P was the highest,6860 μg/g,followed by Ca 4085 μg/g,K 2798 μg/g and Mg 2515 μg/g. And the contents of Fe,Zn,Al,Mn,Cu,Na and B(from high to low)of 5~100 μg/g. At the same time,the harmful elements Pb,Cd,Cr and Ni of heavy metals were detected. Among them,the content of Pb met the limit requirements of national food safety standard GB 2762-2017,and As could not be detected. The method was simple,convenient,efficient and accurate. It was suitable for the determination of many chemical elements in plant samples such as chia seeds.