Highly Sensitive Water Detection Through Reversible Fluorescence Changes in a syn-Bimane Based Boronic Acid Derivative

Abstract

Reported herein is a fluorometric and colorimetric sensor for the presence of trace amounts of water in organic solvents, using <i>syn</i>-bimane based boronate ester <b>1</b>. This sensor responds to the presence of water with a highly sensitive turn-off fluorescence response, with detection limits as low as 0.018% water (v/v). Moreover, analogously high performance was observed when compound <b>1</b> was adsorbed on filter paper, with the paper-based sensor responding both to the presence of liquid water and to humid atmospheres. Reusability of the paper-based sensor up to 11 cycles was demonstrated, albeit with progressive decreases in the performance, and ¹H NMR and mass spectrometry analyses were used to explain the observed, hydrolysis-based sensor response.