A novel molecular imprinted polymer layer electrode for enhanced sensitivity electrochemical determination of the antidepressant fluoxetine

Fluoxetine is a selective serotonin re-uptake inhibitor (SSRI) drug, widely used to treat depression, nervous anorexia, autism and bulimia nervosa. The direct electrochemical behaviour of fluoxetine at a glassy carbon electrode (GCE) was studied in simple aqueous solution using voltammetric techniques. Subsequently, a novel molecular imprinted polymer (MIP) modified GCE was fabricated using itaconic acid and N, N-methylene-bis acrylamide as functional monomer and crosslinking agent, respectively, to produce a sensitive, selective fluoxetine sensor. Precipitation polymerization enabled drop coating of reproducible MIP layers on a GCE as a renewable affinity surface for fluoxetine detection. Initial baseline studies undertaken using CV and SWV allowed for rapid optimization of scan conditions and confirming the irreversible nature of the FXT reaction at a bare GCE but DPV finally allowed for the further and necessary high level sensitivity needed for assays. The binding efficiency and selectivity of the MIP affinity sites for fluoxetine were demonstrated using DPV and responses compared with a non-imprinted polymer layer (NIP). Conditions for MIP formation, loading and incubation were optimized to improve the analytical performance. Under optimized conditions, a linear fluoxetine calibration from 4.99 x 10(-7) to 3.38 x 10-5 mol L-1 was obtained, with detection and quantification limits of 3.33 x 10(-7) mol L-1 (115.01 mu g L-1) and 1.11 x 10(-6) mol L-1 (383.38 mu g L-1), respectively. The sensor was employed to analyse fluoxetine extracted from blood serum.