Electrosynthesis of polypyrrole on steel fiber for solid-phase microextraction of citalopram in serum

A solid-phase microextraction (SPME) technique using steel fiber coated with polypyrrole (PPY) was developed for UV-Vis determination of citalopram in blood serum. The coating was prepared using a three-electrode electrochemical system from an acetonitrile/aqueous (ACN/H2O) oxalic acid solution containing 0.01 M of pyrrole monomer by applying a potential range (0-1.3 V) for 25 min. In order to obtain an efficient film of PPY, experimental parameters related to the coating process were optimized, specifically deposition potential, concentration of monomer, and number of cycles. The effects of various parameters on the efficiency of the SPME process such as extraction time, stirring speed, adsorption and desorption temperature, desorption solvent, and pH of desorption solution were also studied. The coating was stable and adhered to the surface of the steel fiber. The method was linear over about three orders of magnitude with an average correlation coefficient of 0.97. Spiking of blank samples with 0.2 mu g/mL citalopram afforded a recovery of 84% with a precision of 10.2%. A limit of detection of 0.046 mu g/mL (based on S/N = 3) was obtained in the linear dynamic range of 0.046-2.0 mu g/mL. The proposed method was applied to monitor citalopram in serum samples.