A new robust, deep eutectic-based floating organic droplets microextraction method for determination of lead in a portable syringe system directly couple with FAAS.

In the present method, a novel and simple portable in situ deep eutectic-based floating organic droplets dispersive liquid-liquid microextraction method was developed for lead in real food and water samples by a portable microsampling syringe system directly couple with FAAS (DES-µSS). Choline chloride-decanoic acid (ChCl: Decanoic acid (1:1)) was used as a green hydrophobic deep eutectic-based floating organic droplets dispersive liquid-liquid microextraction of lead complex (Pb-2,9 dimethyl-4,7-diphenyl-1,10-phenanthroline) from real aqueous samples. The aqueous solution containing DES was rapidly 10 times sucked up/down by using a micro pipette tip syringe system to properly mix the extraction solvent in the aqueous medium. The whole solution was sucked into the micro pipette tip syringe system and placed in an ice bath for 5 min until decanoic base DES solidify into fine droplets. The solidify metal complex enriched (Pb-2,9 dimethyl-4,7-diphenyl-1,10-phenanthroline) was fine droplets was separated by simply press manually the plunger syringe system inside to expel the lower aqueous to the beaker. The different variables were screened out statistically by using multivariate optimization. Under these optimal conditions, good responses were obtained in the concentration ranges of 2.5-100 µg L. The relative standard deviation (RSD) and enhancement factor were found to be 4.2% and 150, respectively. The limit of detection (LOD) of the proposed method was found to be 0.086 µg L. The t-test was used to check the validity of the proposed method while using CRM samples. It was observed that calculated t value 0.50 less than the t (2.91) at 95% confidence interval which indicating no significant difference between finding and certified values (p > 0.05). The relative % recovery is > 95%, indicated high validity and accuracy of the present method. The method was used to quantify the trace levels of lead in real water and food samples under optimized conditions.