Determination of Rosmarinic acid in plant extracts using a modified sensor based on magnetic imprinted polymeric nanostructures

Abstract

In this work, a modified carbon paste electrode (CPE) was designed and fabricated base on magnetic functionalized molecularly imprinted polymer (MMIP) nanostructure for selective determination of Rosmarinic acid (RA) in some plant extracts. The MMIP nanostructure functionalized with –NH2 group (Fe3O4@SiO2@NH2) was prepared by surface imprinting approach and then used as modifier for destruction of modified sensor. According to sample characterization, nano-sized functionalized MMIP particles (i.e. Fe3O4@SiO2@NH2) with super-paramagnetic behavior was confirmed. The magnetization saturation value of Fe3O4@SiO2@NH2 sample was decreased from 43 emug−1 to 9 emug−1 after MIP coating. In addition, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used for study the electrochemical behavior and determination of RA on the modified CPE. Based on the results, the modified sensor has good sensitivity and selectivity for the detection of RA in the presence of other species compared to unmodified electrodes. Under optimum conditions, two linear concentration ranges (0.1−100 μM and 100−500 μM) with a low detection limit (0.085 μM), and a good precision were obtained. Finally, applicability of the designed sensor was examined for determination of RA in four plant extracts including Salvia officinalis, Zataria multiflora, Mentha longifolia, and Rosmarinus officinalis, successfully.