Comparative Study on Methods for Determination of Glutathione in Fermentation Liquor

Bacteriotome was collected from the bacteria-producing fermentation liquor of glutathione (GSH) by centrifugation,and the GSH was extracted from the bacteriotome by the method of freeze-thaw extraction,by the method of alcohol extraction and by the method of water extraction. Content of GSH in the extract,obtained by either of the 3 above mentioned methods,was then determined by the iodometric titration,the DTNB photometric method,and the HPLC method separately. A comparative study on the results found by the 3 methods was made,and it was shown that best accuracy and selectivety was achieved by the HPLC method,as the interferences from other co-existing anti-oxidants and sulfhydryl-containing compounds were effectively eliminated in this method,and most accurate results were obtained as compared with the other 2 methods. Results obtained by the DTNB photometric method were a little bit higher but quite closer to the results of the HPLC method,and the DTNB photometric method was found to be feasible for routine analysis in large scale production.