Characterization of acidic dyes using Euclidean distance measurements of variables derived from high-performance liquid chromatography–visible multi-wavelength detection data

Abstract

A multi-wavelength analytical procedure is described for identifying the structural features of <100 ng of acidic monoazo dyes using data generated by high-performance liquid chromatography with ultraviolet (UV)–visible diode-array multi-wavelength detection. From a single chromatographic analysis at least 14 variables, including absorbance ratio, peak purity parameters, complementary chromaticity coordinates, UV–visible λ_max values and retention time data can be determined for an eluted dye. By employing a group centroid Euclidean distance measurement (GCEDM) multivariate analytical procedure, these dyes can be classified based on similarities in their chemical structures. The procedure was evaluated by using a group of test dyes and other classes of acidic dyes. The advantages of using GCEDM in preference to either principal component analysis or cluster analysis for obtaining structural information are discussed.