Immobilized Sorption-Colorimetric Microprobes for Chemical Analysis

Abstract

Here, we propose a concept of immobilized sorption-colorimetric microprobes for preconcentration and sensing of colored analytical forms. Individual particles of sorbents distributed over a small area of 1 mm × 1 mm and attached to an easy-to-made strip with an adhesive layer were considered as the probes producing colorimetric responses through preconcentration of colored analytical forms. These responses were then directly recorded with a scanner at 1200 dpi, separated from a background, and processed to obtain information about the amounts of analytes. The food dyes Fast Green FCF, and Ponceau-4R were used as the proof-of-concept colored analytes. The microprobes based on silica modified with quaternary ammonium bases and on alumina were studied. Some features of the analytes’ adsorption by the probes and their scanometric sensing were found. It was shown that the proposed method is applicable for the determination of 1–7 mg L−1 of the dyes.