Fabrication of a fluorescent nanoprobe for determination of sulfadiazine after its dispersive solid-phase extraction using magnetic nanocomposite sorbent

A sensitive and non-toxic fluorescent nanoprobe has been designed for the determination of sulfadiazine. Sul-fadiazine was separated and preconcentrated by dispersive solid-phase extraction based on the magnetic nanocomposite sorbent of oxidized nanocellulose/polyethyleneimine/nitrogen graphene quantum dots. The quantification of sulfadiazine was based on the decrease in the fluorescence of Ag2S@L-cysteine quantum dots. In optimal conditions, the fluorescence of Ag2S@L-cysteine quantum dots linearly decreases with the increase of sulfadiazine concentration within the range of 2.0-40.0 & mu;g L-1. A limit of detection (LOD) of 0.41 & mu;g L-1 and intra-and inter-day precision of 2.1%, and 4.3%, respectively, at the sulfadiazine concentration of 8.0 & mu;g L-1 (RSD%, n = 7) were obtained. The maximum sorption capacity of the magnetic nanocomposite sorbent for sulfadiazine was found to be 39.0 mg g-1. The proposed procedure was successfully used to extract and quantify sulfadiazine from a variety of samples.