Separation and preconcentration system based on silver nanoparticles assisted ionic liquidmicroextraction for determination of zinc in water and food samples by stopped-flow injection spectrofluorimetry

For the first time, silver nanoparticles assisted in situ solvent formation microextraction (AgNPs-ISFME) was combined with stoppedflow injection spectrofluorimetry (SFIS) for the determination of zinc. In the proposed approach, thiamine was oxidized with zinc (II) to form hydrophobic and highly fluorescent thiochrome (TC), which wassubsequently extracted into ionic liquid as an extractant phase. A small amount of an ion-pairing agent was added to the sample solution containinga water-miscible ionic liquid to form a hydrophobic ionic liquid. After centrifuging, phase separation was performed and the enriched analyte wasdetermined by SFIS. AgNPs-ISFME is an efficient method for separation and preconcentration of metal ions from aqueous solutions with high ionicstrength. The variables affecting the analytical performance were studied and optimized. Under optimum experimental conditions, the proposedmethod provided a limit of detection (LOD) of 0.035 μg L-1 and a relative standard deviation (RSD) of 2.5%. Finally, the proposed method was successfully applied to zinc determination in water and food samples

Keywords:

In situ solvent formation microextraction , Stopped-flow injection spectrofluorimetry , Ionic liquid , Zinc