Construction of a sensitive and selective sensor for morphine using chitosan coated Fe3O4 magnetic nanoparticle as a modifier

A simple and sensitive sensor based on carbon paste electrode (CPE) modified by chitosan-coated magnetic nanoparticle (CMNP) was developed for the electrochemical determination of morphine (MO). The proposed sensor was characterized with scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrooxidation of MO was studied on modified carbon paste electrode using cyclic voltammetry, chronoamperometry and differential pulse voltammetry as diagnostic techniques. The oxidation peak potential of morphine on the CMNP/CPE appeared at 380mV which was accompanied with smaller overpotential and increase in oxidation peak current compared to that obtained on the bare carbon paste electrode (CPE). Under optimum conditions the sensor provides two linear DPV responses in the range of 10–2000nM and 2–720μM for MO with a detection limit of 3nM. The proposed sensor was successfully applied for monitoring of MO in serum and urine samples and satisfactory results were obtained. [Display omitted] •A sensitive and selective voltammetric sensor for MO by using a carbon paste electrode modified with CMNP was introduced.•CMNP as a new modifier facilitates the charge transfer of MO oxidation process.•The proposed sensor was used successfully for MO determination in biological fluids such as serum and urine samples.•This sensor is fabricated easily and has good stability and high sensitivity.