Spectrophotometric determination of paracetamol using Hydrogel based semi solid-liquid dispersive microextraction

A simple, fast and inexpensive method based on dispersive liquid-liquid microextraction (DLLME) and dispersive solid-phase extraction (DSPE) has been developed for preconcentration and spectrophotometric determination of paracetamol (PC) using pH-sensitive hydrogel (HG). In this study we demonstrate a novel microextraction technique, entitled “semi solid-liquid dispersive microextraction” which can be successfully used for preconcentration of analytes of interest from aqueous samples. The procedure involves the oxidation of paracetamol by Fe(III) and a subsequent reaction with ferricyanide in the presence of HCl to yield Prussian Blue (PB) complex. In the extraction step, appropriate amounts of poly(styrene-alt-maleic anhydride), as a pH-sensitive hyrogel, was injected into the aqueous solution, so a cloudy solution was formed. Organic and inorganic compounds having the potential to interact with polymer particles could be extracted into the organic phase. For our case PB complex could be extracted to the cloudy phase. After centrifugating, the hydrogel-rich phase was sedimented at the bottom of centrifuge tube. The absorbance of the sedimented phase diluted in methanol was measured at the absorption maximum of 733 nm (λmax of PB in hydrogel). The absorbance was linear to paracetamol concentration in the range of 0.01-0.5 μg mL-1 with a correlation coefficient of 0.995.