An Electrochemical Sensor Based on Molecularly Imprinted Polymer for Methyl Paraben Recognition and Detection

Esters of 4-hydroxybenzoic acid, known as parabens, are used as antimicrobial preservatives in cosmetic and pharmaceutical products. The presence of parabens in human body mostly originates from the topical implementation of personal care products. The adverse health effects of parabens include endocrine disruption, oxidative DNA damage, contact dermatitis, and allergenic reactions. In this study, surfaces of pencil graphite electrodes were modified by electropolymerization of p-phenylenediamine conducting polymer imprinted with methyl paraben (MP) to develop a sensor for MP detection. Electrochemical deposition was performed by cyclic voltammetry in a potential range of 0.0-0.8 V at a scan rate of 25 mV/s in 10 cycles. Polymer growth and template leach conditions were systematically investigated for determining optimal settings in developing the sensor. Under optimal working conditions, the differential pulse voltammetric current response of MP oxidation was linear in the range of 10-50000 mu M (R-2 = 0.9682) with a detection limit of 10 mu M (S/N ratio of 10). The molecularly imprinted polymer modified electrode showed an excellent selectivity and sensitivity towards MP compared to its structural analogues. The developed sensor was successfully applied to the detection of methyl paraben in four samples of pharmaceuticals and a personal care product.