Determination of trace copper(II) by Triton X-100 sensitized fluorescence quenching of a novel calix[4]arene Schiff base derivative

Fluorescence quenching by copper(II) of a Schiff base derivative of p-tert-butylcalix[4]arene (SANCAX) in 0.1% polyethylene glycol tert-octylphenyl ether (Triton X-100) medium was investigated. The fluorescence of SANCAX is quenched by Cu2+ due to the formation of a weaker fluorescent inclusion complex (Cu-SANCAX). The fluorescence quenching (ΔF = FSANCAX − FCu-SANCAX) is sensitized in Triton X-100. Under optimal conditions, the linear range calibration curve for the determination of Cu2+ is 0.005–0.08 μg mL−1. The detection limit is 3.05 ng mL−1 with an RSD of 1.55% (n = 3, c = 0.05 μg mL−1). The SANCAX fluorescence quenching mechanism was investigated by the Benesi–Hildebrand method, fluorescence quantum yield, and IR. The method has been applied in the determination of trace Cu2+ in real samples with satisfactory results.