Application of standard addition method in the determination of powder samples by LA-ICP-MS

The application of standard addition method in the determination of powder samples by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was studied by the solid-solid mixing sample preparation method. Taking precious metals in automobile exhaust catalyst as the target, silica gel (DMT) with 2, 4-dimercapto1,3, 5-triazine functional group was selected to adsorb different contents of precious metals, and then mixed with automobile exhaust catalyst to press the mixed powder into disc. Intensity of each element was measured by LA-ICP-MS, and the content of precious metal in the automobile exhaust catalyst was calculated by standard addition method. The selection of silica gel with different functional groups, the influence of pH value on the adsorption of precious metals, and the influence of sample preparation methods on the uniformity of the sample were discussed. Results showed that the optimal pH value for adsorption of precious metals was 3. 85, and the uniformity and repeatability of grinding samples were better. This method was used in the determination of certified reference materials for the analysis of automobile exhaust catalysts, and the results are consistent with the certified values. © 2021, Youke Publishing Co.,Ltd. All rights reserved.