Determination method of total selenium, inorganic selenium and organic selenium content of yeast selenium

Abstract

The invention discloses a method for determining the content of yeast selenium total selenium, inorganic selenium and organic selenium. After the sample is heated and digested by acid, the selenium in the sample is uniformly reduced to tetravalent selenium in the hydrochloric acid medium, and the tetravalent selenium reacts with 2,3-diaminonaphthalene (DAN) under slightly acidic conditions to form kohlrabi selenium. , extracted with cyclohexane. Fluorescence intensity was measured with a fluorescence photometer to calculate the selenium content in the sample. The determination of total selenium uses 3 mL mixed acid, which greatly reduces the amount of mixed acid; digestion and extraction are carried out in a water bath in a capped round bottom flask, which can avoid the pollution of the laboratory environment by strong redox acid, and can also Prevent the volatilization loss of selenium and obtain a higher recovery rate; cancel the use of cresyl red indicator, avoid the interference of the sample on the judgment of the color change of the indicator, and also reduce the interference of the indicator to the liquid to be tested. The determination time of total selenium and inorganic selenium is greatly shortened, and the digestion of total selenium and the extraction of inorganic selenium can be completed in about one hour at the same time.

Description

technical field

[0001] The invention relates to a method for determining the content of selenium in yeast selenium, especially the content of organic selenium. Background technique

[0002] In 1974, the US Food and Drug Administration (FDA) began to allow selenium to be added to livestock, poultry and pig feed. So far, the research and application of inorganic selenium and organic selenium have entered a wider field (Ullrey, 1992). One of the most economical sources of organic Se is the enrichment of inorganic Se by yeast (Neve, 1998). Yeast can absorb carbon, nitrogen, phosphorus, sulfur and minerals as well as trace elements, because selenium and sulfur are congener elements with similar physical and chemical properties, making them replace sulfur in yeast cell biosynthesis reactions (Jian Zheng, 2003), selenium-enriched yeast is a microbial fermentation product produced by adding inorganic selenium such as sodium selenite during yeast culture to convert it into organic ...

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