Colorimetric chemosensor for spermine based on pyrocatechol violet and anionic phenylboronic acid in aqueous solution

Abstract

A new sensing method for colorimetric detection of spermine has been developed using a simple mixture of anionic pyrocatechol violet (PV) and 3-carboxyphenylboronic acid (CPB) in a neutral aqueous solution. In the absence of spermine, the boronate ester between PV and CPB formed to a small extent, resulting in slight spectral and insignificant color changes. The addition of spermine to the mixture caused solution color change from yellow to reddish-brown with a bathochromic shift in absorption spectra by the boronate ester formation between PV and CPB against the electrostatic repulsive interactions, while basic amino acids and other amines induced no or minimal color and spectral changes. The detection limit was determined to be 6.24 μM for spermine, which was within the critical concentration for cancer diagnosis. The mixture was demonstrated as a novel colorimetric chemosensor for spermine with high sensitivity and sensitivity. This present study can contribute to the facile method for colorimetric detection of cationic analytes by mixing anionic catechol dyes and similarly charged boronic derivatives.