抄録
As one of studies on the application of microbiological assay method for sulfate using E. coli B (H), determination of sulfur content in orange leaves was examined. Preparation of sample solution was as follows : Dried orange leaves were subjected to combustion in the presence of Mg (NO3)2·6H2O as an oxidizing agent at 800°for 1 hr. The residue was dissolved in 3 N HCl, neutralized with 3 N KOH, and the solution was passed through a column of Amberlite IR-120 (H+form). The effluent was used for the microbiological assay, and the results obtained were as follows : 1) It was possible to determine sulfur content in orange leaves by microbiological assay method using Mg (NO3)2·6H2O as an oxidizing agent. 2) This microbiological method gave small standard deviation (σ=3.8%) and accurate recovery (98.1-101.5%). 3) This proposed microbiological method will make it possible to determine sulfur content in orange leaves with the amount of a sample less than that in the gravimetric method.
