A Novle Quinoline Hydrazone-Based Fluorescent Probe for Sequential Determination of Cu2+/Glyphosate and Its Applications

A novel quinoline hydrazone-based fluorescent probe L was designed and synthesized using quinoline-2-carboxylic acid and 7-(diethylamino)coumarin-3-carbaldehyde as raw materials. The spectral properties of probe L were studied by UV-Vis/fluorescence spectrophotometry. The results showed that probe L had obvious ON-OFF fluorescence response to Cu2+ in the tetrahydrofuran (THF)/H2O [V:V=3:7, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES) 10 mmol/ L, pH=7.4] solution, and it displayed efficiency, high specificity and sensitivity. Job's plot and high resolution mass spectrometry showed that the stoichiometry of L-Cu2+ complex was estimated to be 1:1. Meanwhile, complex L-Cu2+ showed high selectivity and good anti-interference ability towards glyphosate through the significant fluorescence enhancement, and the detection limit of complex L-Cu2+ to glyphosate could reach 5.6x10(-8) mol/L (9.5x10(-3) mg/L). In addition, complex LCu2+ was able to sense glyphosate by "naked-eye" according to the color change, and applied to glyphosate detection in the actual water samples.