Hydroxyazo dyes as metal ion indicators

Abstract

Introduction Discovery and early investigation Use of Eriochrome Black T as a metal ion indicator 3 Preparation of a Pure Form of Eriochrome Black T. . Attempts to purify commercial samples of the dye Preliminary study of the magnesium dye compound at pH 8 by the log-ratio method 18 Synthesis of Eriochrome Slack T 23 Procedure for the preparation of a pure form of Eriochrome Black T 28 Conclusions 31 Analysis and Characterization of Eriochrome Black T Crystals Elemental analysis Detection and determination of dime t lay lamine from the crystalline dye 33 Determination of neutralization equivalent. . 35 Determination of moisture content 39 Summary of analytical results 40 Conclusions Free Acid Form of Eriochrome Black T Preparation of the free sulfonic acid Study of the free dye acid Eriochrome Black T and Its Calcium and Magnesium Derivatives Apparatus and materials Acid dissociation constants of Eriochrome Black T ..«.a 45 Beer's law study of the purified dye and the molar extinction coefficient 55 Log-ratio study of the calcium and magnesium. compounds of Eriochrome Black T