A highly selective and sensitive pyridylazo-2-naphthol-poly(acrylic acid) functionalized electrospun nanofber fuorescence ‘‘turn-off’’ chemosensory system for Ni2+

Abstract

A fluorescent nanofber probe for the determination of Ni2+ was developed via the electrospinning of a covalently functionalized pyridylazo-2-naphthol-poly(acrylic acid) polymer. Fluorescent nanofbers with diameters in the range 230–800 nm were produced with uniformly dispersed fuorophores. The excitation and emission fluorescence were at wavelengths 479 and 557 nm respectively, thereby exhibiting a good Stokes’ shift. This Ni2+ probe that employs fluorescence quenching in a solid receptor–fluorophore system exhibited a good correlation between the fluorescence intensity and nickel concentration up to 1.0 mg mL 1based on the Stern–Volmer mechanism. The probe achieved a detection limit (3d/S) of 0.07 ng mL 1and a precision, calculated as a relative standard deviation (RSD) of <4% (n ¼ 8). The concentration of Ni2+ in a certified reference material (SEP-3) was found to be 0.8986 mg mL 1, which is significantly comparable with the certified value of 0.898 mg mL 1. The accuracy of the determinations, expressed as a relative error between the certified and the observed values of certified reference groundwater was#0.1%. The versatility of the nanofber probe was demonstrated by affording simple, rapid and selective detection of Ni2+ in the presence of other competing metal ions by direct analysis, without employing any further sample handling steps