Highly sensitive and selective determination of cupric ions by using N,N'-bis(salicylidene)-o-phenylenediamine as fluorescent chemosensor and related applications.

A sensitive and selective copper(II) fluorescence Schiff base chemical sensor receptor 1 (short for N,N'-bis(salicylidene)-o-phenylenediamine) has been prepared. The fluorescence of receptor 1 in pH 8.2 phosphate buffer solution can be dramatically quenched by Cu(2+), whereas it is nearly unaffected by other metal ions. Based on this, a sensitive and selective fluorescent quenching method for Cu(2+) detection has been established. Under the optimum conditions, a good linear relation exists between the quenching efficiency (F0/F) and the concentration of Cu(2+) in the range of 1.0 × 10(-7)-2.5 × 10(-6) mol L(-1). The detection limit (3σ) for Cu(2+) determination is 2.0 × 10(-8) mol L(-1). The present method has been successfully used for quantification of Cu(2+) in soybean milk powder. Furthermore, the fluorescence switch property of the system was explored, and the system might be applied for determination of glutathione and construction of molecular logic gate.