Analysis of Selenium Contents in Selenium-rich Wine Grape and the Vinification Products Based on Hydride Generation Atomic Fluorescence Spectrometry

A new method was established for the determination of total selenium and inorganic selenium in wine grapes by hydride atomic fluorescence spectrometry (HG-AFS) and the changes of selenium contents were traced and analyzed in the wine grapes applied selenium-enriched foliar fertilizer and its vinification products. The sample was digested with HNO₃-HClO₄ (4+1) at 180℃,reduced with hydrochloric acid at 100℃,and then the total selenium was determined by HG-AFS. The sample was extracted with water,acidified,passed through Cleanert PCX cartridge,digested and reduced,and then the inorganic selenium was determined with the same way. Results showed that a good linearity (0.25~4 μg/L) was obtained with R² value of 0.9989;the detection limit was 2 μg/kg. The limit of quantification was 5 μg/kg. The recoveries of total selenium were 96.47%~97.39% and relative standard deviations were 1.76%~5.65%. The recoveries of inorganic selenium were 85.20%~88.91% and the standard deviations were 5.97%~21.45%. The tracing test showed that the total selenium content in the wine grapes applied selenium fertilizer increased 3 times with the content of 9.65~38.6 μg/kg by contrasting to the controls. The inorganic selenium was detected in neither wine grapes tested nor controls. After vinification,the selenium fraction in the wine residues,lees and wine,were 89.3%,8.7% and 2.0% respectively. Through applying selenium foliar fertilizer,the selenium in wine grapes significantly increased to the value required by criterion of selenium-enriched food. However,selenium was mainly lost with the separation of wine residue and lees during vinification,and only a small amount remained in the wine.