A Novel Electrochemical Sensor Based on Plastic Antibodies for Vitamin D3 Detection in Real Samples

A highly sensitive voltammetric sensor for vitamin D3 is designed and build by the electropolymerization of molecularly imprinted polymer (MIP). Vitamin D3 selective MIP is synthesized by the electropolymerization of p-phenylenediamine–resorcinol mixture on the screen-printed carbon electrode (SPCE) surface in the presence of the vitamin D3 molecules. The electropolymerization of monomers made a film deposition on electrode surface which absolutely suppressed the reduction of ferricyanide. The removal of the vitamin D3 creates the cavities which caused noticeably increased ferricyanide signal, which was again suppressed after the rebinding of vitamin D3. It was shown that the decrease of the ferricyanide peak of the MIP electrode was affected linearly by vitamin D3 concentration. Various factors, by which the response current of the electrode is mainly affected, were studied and optimized. This sensor shows a linear response range of $1 \times 10^{-11}$ – $2 \times 10^{-9}$ M and lower detection limit of $1 \times 10^{\mathbf {-12}}$ M. The sensor was successfully applied for the detection of vitamin D3 in human plasma samples.