ABSTRACT
A new all-solid state electrode modified with poly ( o-aminophenol-co-o-phenylenediamine ) film was prepared by cyclic voltammetry.The electrochemical response of the electrode to various solutions in the available acidity range of 1.00 × 10-12-10.0 mol/L was studied by cyclic voltammetry.The results showed that the reduction peak potentials and the available acidity of solution showed good linear relationship in 3 stages of 1.00×10-10-0.10 mol/L, 0.10-2.00 mol/L and 2.00-10.0 mol/L respectively, and the regression equations were Epc=0.0456lgC(H+)-0.295, Epc=0.0803c(H+)-0.309, and Epc=0.0278c(H+)-0.188, respectively.There were similar responses in the solutions of H2 SO4 , HNO3 and HClO4 in the concentration range of 1.00-8.00 mol/L.The preparation method of electrode was simple, and the determination range of available acidity was as wide as 1.0 ×10-10-10.0 mol/L, which laid the foundation for the development of solid-state electrochemical sensors for determination of acidity of high acidity solution.
ABSTRACT
An electrochemical sensor has been developed for the selective determination of chlortetracycline ( CTC) using the molecularly imprinted technique. A molecular imprinted polymer ( MIP) on the surface of a glassy carbon electrode ( GCE ) was prepared by electropolymerization of o-aminophenol ( OAP ) in the presence of CTC in the sodium perchlorate ( NaClO4 ) solution using cyclic voltammetry ( CV ) . The electrochemical performance of the sensor was studied by using differential pulse voltammetry ( DPV ) . A linear relationship between the peak current difference and the CTC concentration was found in the range of 2. 0×10-8-6. 1×10-7 mol/L with the detection limit of 1. 5×10-8 mol/L (3σ). After regeneration by washing with the mixture of methanol and sulfuric acid, the sensor showed excellent reproducibility and good stability. The MIP electrode exhibited almost no response to chloramphenicol and penicillin, and very weak responses to tetracycline and oxytetracycline, proving a good selectivity. Recoveries of standard addition measured in the actual samples of milk and chicken meat were between 86 . 4% -96 . 9%. Compared with the reported methods, this sensor showed a low detection limit, simple operation without derivatization, rapid response and low cost.
ABSTRACT
The sensor of naringin(NG), a non-electroactive substance, was prepared based on the molecular imprinting technique.Using cyclic voltammetry technique (scan rate is 100 mV/s), the naringin imprinting sensitive film, poly-o-aminophenol was coated on the surface of a graphite electrode in the presence of naringin which was considered as the template, and characterized by SEM and X-ray reflective spectrophotometry (XRR).Using K_3Fe(CN)_6 as an electroactive marker, the electrochemical properties of the NG sensor were investigated by CV, electrochemical impedance spectroscopy (EIS), differential pulse voltammmetric and chronoamperometric.The results showed that the imprinted electrode was significantly different from the non imprinted electrode in morphologies and electrochemical properties, and a linear relationship between the peak current and the naringin concentration was found in the range of 6.0 × 10 ~(-5)-1.4 × 10 ~(-4) mol/L with a detec tion limit of 1.6 × 10 ~(-5) mol/L.Moreover, the imprinted electrode exhibited a good selectivity and rapid response to the naringin template molecules, as well as an excellent reproducibility(RSD = 1.8 %, n=5).