Modeling the Dichromatic Behavior of Bromophenol Blue to Enhance the Analytical Performance of pH Colorimetric Sensor Arrays

The dichromatism of Bromophenol blue (BPB) was investigated by varying its concentration in the absence and presence of surfactant. A model of the indicator behavior was carried out, justifying the experimental shapes of the sigmoidal profiles of the hue (H) coordinate. The model applied to the solution was compared with the performance of colorimetric sensor arrays (CSAs) with increasing BPB concentrations. The H shape and the prediction errors of the CSAs were very similar to those predicted. The experimental results enable the changing of the slope of the calibration profiles, at will, by varying only the BPB concentration.