金属キレート陽イオンによる陰イオンの溶媒抽出吸光光度定量(第27報) : デヒドロ酢酸の新しい比色定量法

抄録

A new spectrophotometric method is proposed for the determination of dehydroacetic acid (DHA). The present method is based on solvent extraction into nitrobenzene of the ionpair formed between tris (1, 10-phenanthroline) iron (II) and the anion of DHA. The maximum absorbance of the extract in the organic phase is at 516 mμ. In order to obtain optimum conditions for the determination of DHA, various factors were studied. The maximum and constant extraction is obtained in the range of pH 8.5∼13. Calibration curve was found to be linear for the range (2.4×10^-5∼2.88×10^-4M) of DHA concentration tested in aqueous solution. The effect of other food additives on this method was investigated. Saccharose, glycine, sodium citrate, starch, and sodium chloride do not interfere with the determination in a 10-to 100-fold molar excess. A small amount of saccharine sodium, salicylic acid, sodium cyclamate, and coloring matters gives a positive error. The proposed method has higher sensitivity and better accuracy.