Application of an ionic-liquid combined with ultrasonic-assisted dispersion ofgold nanoparticles for micro-solid phase extraction of unmetabolized pyridoxine and folic acid in biological fluids prior to high-performance liquid chromatography

Abstract

In this study, a facile and efficient protocol was suggested for the synthesis of gold nanoparticles (Au NPs) and their subsequent transfer to aqueous solution by the application of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, following vigorous shaking with ultrasonic waves. The produced sorbent was applied for the micro-solid phase extraction of pyridoxine and folic acid from biological samples. This combination is associated with a high extraction efficiency for the preconcentration and determination of pyridoxine and folic acid in biological samples. The dependency of the extraction efficiency on traditional parameters like the extraction time, sample pH, volume of the ionic liquid, amount of Au NPs, sample volume, salting effect, desorption time and eluent volume was optimized using an experimental design combined with response surface methodology. Under optimized conditions, the suggested method shows a high linear range (20–500 ng mL⁻¹) with limits of detection (LODs) of 3.4 and 4.8 ng mL⁻¹ for pyridoxine and folic acid, respectively. The precision values (RSDs, n = 5) were 2.5 and 3.3% at a concentration level of 50 ng mL⁻¹ for both species, while the validated method was successfully used for pyridoxine and folic acid quantification with relative recoveries in the acceptable range of 83–104% and RSDs less than 4.1%.