Abstract:A method for the determination of 16 mineral elements, such as K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr and Pb in walnut was developed by total reflection X-ray fluorescence (TXRF) with constant pressure digestion. The optimized temperature and time of the constant pressure digestion were 180 ℃ and 4 h, respectively. The certified reference material (CRM, GBW10026) was digested and determined. And the lower limit of detection (LLD) and the limit of determination (LDM) of different element in walnut were calculated. calculated to be 0.001~0.045 mg/L and 0.003~0.144 mg/kg, respectively. TXRF analytical results showed that the 16 mineral elements in the CRM consistent were within the standard value ranges. This method showed advantages in lower cost of the pretreatment equipment, easy operation, less sample consumption and low detection limit. The contents of 16 mineral elements in walnut determined by this method showed little difference with the results by ICP-MS. The relative standard deviations (RSD) of TXRF were lower than 3.9%.
