An Improved Analytical Method for the Analysis of Reactive Dyes by High Performance Liquid Chromatography

Abstract

High Performance Liquid Chromatography or HPLC is a technique that is commonly used for the analysis of many different compounds. For the analysis of reactive dyes, ion-pair chromatography (IPC) is often implemented, but previous methods in the literature are a decade old and have not allowed for the analysis of highly complex dyes such as Reactive Blue 21, a copper pthlalocyanine reactive dye.

In this work, IPC of reactive dyes is improved by examining a variety of different factors. Factors examined were ion-pair reagents and column stationary phases. Gradient adjustments, including gradient elution, curve, and time were examined to improve the analysis of Reactive Blue 21. Reactive Blue 21 is further examined through hydrolysis and two dyeings, exhaust dyeing and pad batch. A proposed grouping of peaks, referring to the structure of Reactive Blue 21, is given from the hydrolysis experiment, and the peaks are comparable to those shown in the two dyeings. Tetrabutylammonium bromide (TBAB), an ion pair reagent, along with the Atlantis C18 column provided the best analysis for the reactive dyes studied. For Reactive Blue 21, decreasing the slope of the gradient curve greatly increased the number of peaks resolved. Subsequently, these peaks could be ascribed to the hydroxyethylsulfone (HES), vinyl sulfone (VS), or sulfatoethylsulfone (SES) forms of the dye based on the rate of change of peak percent area shown in the hydrolysis and dyeing experiments.