Aspects of the analytical chemistry of basic dyestuffs

The existing basic dye procedures for the quantitative determination of anions have been critically reviewed and criteria for successful application of these dyes established. The solution chemistry of Brilliant green has been studied in some detail and the extraction criteria established by reference to model systems. Procedures have been established for the determination of perrhenate, perchlorate, tetra-chloroaurate (III), hexachloroantimonate (V) and tetrachloro-thallate (III) with Brilliant green. In addition, the systems of tetrachlorogallate (III), tetrabromoindate (III), and dicyanoargentate (I) have been investigated. The analysis and purification of basic dyestuffs has been studied and the literature reviewed. Quantitative procedures, including semi-micro Kjeldahl nitrogen determinations, titanium (III) chloride reduction, non-aqueous potentiometric titrimetry, and precipitation by 12-tungstosilicic acid have been experimentally investigated. A comparative study of these methods was undertaken and the relevance of the purity values obtained by each method critically discussed. Other dye systems were investigated, including Safranine 0 and Sevron Red GL, and procedures evolved for antimony in steel and gold, respectively. The criteria for an ideal dye for use in highly acidic solutions are discussed and Flaviduline 0, and Phenazinduline 0 synthesized in an attempt to produce a suitable species. In the light of the experimental work carried out, and in view of the present extent of theoretical explanations of these systems, the nature of the ion association extraction processes has been discussed along with some possible future developments.