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

Abstract

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 = F_SANCAX − F_Cu-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.