Alginate-based hydrogel fiber as a restricted access material for microextraction of drugs in biological samples

A novel lab-made alginate-based hydrogel device was successfully prepared and applied as a sorption material for the solid-phase microextraction of drugs (fluoxetine and its metabolite, norfluoxetine) in human plasma, with subsequent determination by high performance liquid chromatography–fluorescence detection (HPLC-FD). When supported in a polypropylene hollow fiber, the alginate was able to extract the analytes and functioned as a restricted access material, excluding >95 % of proteins from the biological matrix. The results indicate the potential use of this phase/device for quantitative drugs extraction from biological matrices at concentrations compatible with those typical in the literature (0.5 μg mL−1), and with satisfactory precision (13.4 % for fluoxetine and 6.2 % for norfluoxetine). Such outcomes, promoted by a simple and inexpensive material, open a new perspective of exploration of hydrogels as the sorption phase in biological matrices, a concept previously unexplored in the literature.