Potentiometric and Spectrophotometric Flow Injection Determination of Variamine Blue

Original Paper

Abstract

Simple, rapid, and sensitive potentiometric and spectrophotometric methods were developed for flow injection determination of variamine blue (VB) dye. Novel variamine blue carbon paste electrodes (VB-CPEs) were constructed and characterized for flow injection potentiometric determination of VB. The fabricated electrodes work satisfactorily in the concentration range from 10^-6 to 10^-2 M and sampling through output 60 sample h^-1. The proposed spectrophotometric method was based oxidation on oxidation of VB with potassium persulfate, forming a deep violet blue colored quinonedimine species with an absorption maximum at 550 nm. FIA parameters such as reagent concentration, flow rate, sample volume and length of reaction coil were optimized to achieve the highest sensitivity, and sample output, with the advantage of accuracy and automation feasibility. Calibration graphs were linear in the concentration range from 4.6 to 80.0 µg VB and sampling through output 40 sample h^-1.