Comparison of three common pre-treatment methods for the determination of lead contents by GFAAS in Chinese health-care wines

摘要

Sample pre-treatment plays an important role in sample analysis, which directly affects the accuracy and reliability of the results. In this work we studied the influence of three common sample pre-treatment methods (direct injection, microwave digestion and wet digestion) on the determination of lead (Pb) content of Chinese health-care wines by graphite furnace atomic absorption spectro-metry (GFAAS). Six different brands of Chinese health wines were selected for the research. After each Chinese health-care wine was digested by three digestion methods, GFAAS was used to detect the Pb content of the samples. For the selected six different health-care wines, the results showed that the Pb content obtained by GFAAS with different pre-treatment methods were different. Microwave digestion had the best recovery, and was proposed to be applied to the pre-treatment of many kinds of health-care wines, while the direct injection method might be suitable only for health-care wine with lesser amounts of ingredients such as sugar. In the practical work, due to the complexity of the base composition of Chinese health-care wines, currently there is no relevant standard analysis method for the pre-treatment of Chinese health wines. According to the accuracies of the three chosen common pre-treatment methods, it was proposed that microwave digestion might be more suitable as a standard digestion method for the determination of Pb in Chinese health-care wines. This work could provide theoretical support for the further establishment of a standard analytical method for the determination of lead and other (heavy) metal elements in Chinese health wines by GFAAS and other methods.