Selenium Surveillance: A New Option for China to Examine Selenium Contents in Major Sources of the Chinese Diet

China continues to face severe health effects from selenium overconsumption and underconsumption. To monitor the intake of selenium from foods, we collected 12 kinds of food samples representing major sources of food from 14 provinces in China. We treated samples with nitrate and hydrogen peroxide in microwave digestion. Using Y 89 as the internal standard, we determined selenium contents in foods with inductively coupled plasma mass spectrometry (ICP‐MS). Detection limit of the method was 0.03 ng/mL; the linear range was between 0‐500 ng/mL; and the linear coefficient(r) was better than 0.9995. We evaluated precision and accuracy of testing by analyzing NIST 1568a and 1566b standardized reference materials. On average, selenium contents are 0.02‐0.1 mg/kg among milk products, below 0.1 mg/kg among cereals, beans, tubers, vegetables and fruits, sugar, alcoholic and non‐alcoholic beverages, 0.10‐0.13 mg/k among meats, 0.25‐0.50 mg/kg among eggs, 0.6‐1.2 mg/kg among animal kidney and liver. Selenium contents vary widely among sea foods from 0.1‐1.2 mg/kg. Selenium contents differ significantly among food produced in different regions and are linked with earlier research on the health effects of selenium. This suggests monitoring of major sources of selenium may be a useful marker for identifying early emerging high or low selenium intake patterns in different regions.