A novel coumarin based fluorescent sensor for high-sensitive detection of Cu2+and water as well as applications in food and environmental analysis

A novel fluorescent sensor (SZ) based on coumarin was designed and synthesized for the detection of Cu2+ in DMSO/H2O solution (9/1, v/v, pH = 7.4, HEPES = 10 mM) and water in organic solvents. The sensor exhibited a low detection limit of 9.6 x 10- 8 mol/L and a short response time (30 s) for Cu2+ in DMSO/H2O solution. SZ showed a red-shift in emission wavelength in more polar solvents and demonstrated high sensitivity in detecting water in various solvents including tetrahydrofuran, acetone, ethanol, methanol and acetonitrile with the lowest detection limit in ethanol as low as 0.0035 % (v/v). The mechanism for water detection by SZ was identified to be polarity dependent. Moreover, SZ was effectively employed for detecting alcohol content in Chinese Baijiu, as well as water content in sugar and salt samples. Notably, SZ has the capability to determine Cu2+ in soil and environmental water samples, showing a wide range of potential applications.