Optode Membrane for Detecting a Wide Range of Water Content in Organic Solvents

Abstract

To develop an optode membrane with a high sensitivity and a wide detection range, a photoinduced electron transfer fluorescence dye (FWSA) possessing an acrylate moiety was synthesized and covalently immobilized on a 2‐hydroxyethyl methacrylate‐based network polymer matrix. The prepared membranes displayed the fluorescence “turn‐on” detection of water over a wider operating sensing range. The sensitivity of the optode membrane was influenced by the crosslinker. The sensitivity of the membrane M1 using dimethacrylamidated poly(dimethylsiloxane) (AMPS) as a crosslinker was superior to that of M2 and M3 membranes using tetra‐ or triethylene glycol dimethacrylate. As the water content was increased from 0 to 80% in water‐miscible organic solvents, the M1 membrane showed a gradual fluorescence enhancement. The sensing performance of the M1 membrane was evaluated for aqueous methanol, ethanol, acetone, and dimethyl sulfoxide solutions in terms of the detection range, response time, reproducibility, and stability.