Separation and preconcentration of hemin from serum samples followed by voltammetric determination

Extra concentrations of hemin are toxic since it may intercalate in lipid membranes and catalyze the formation of hydroxyl radicals resulted in the lysis and death of the cell. So, we have proposed a novel green approach for the determination of hemin in biological samples. Due to the complexity of the matrix of these samples, an efficient extraction procedure has been also involved in the approach. An ammonium-based task-specific ionic liquid containing salicylate anion was synthesized and used for the extraction and pre-concentration of hemin trough a dispersive liquid phase microextraction. Hemin was extracted into a few micro liters of the ionic liquid and so, separated from the sample matrix. Differential pulse voltammetry followed the extraction process for the quantification of hemin in the IL-rich phase separated from the sample and placed on the surface of a glassy carbon electrode. In the presented approach, the ionic liquid was used as both the extracting solvent (due to its polarity and water-immiscibility) and the electrode modifying agent (due to its ionic structure). The peak current obtained from the electrochemical reduction of hemin was used as the analytical signal correlated to the concentration of hemin. Different experimental parameters affecting both the extraction and electrochemical processes were optimized. Under the optimized conditions, a linear concentration range of 0.020-2.60 μM with a detection limit of 3.16 × 10− 3 μM was obtained. The proposed methodology was successfully applied to the determination of hemin in a mouse serum sample indicating its applicability to complex media.