Abstract:In the present study, a new biosensor based on lipase from Candida rugosa (CRL) was developed for amlodipine besylate drug (AMD) with biodegradable material using a mixture of polyaniline iron oxide and gelatin. Polyaniline/Fe 2 O 3 (PANI@Fe 2 O 3 ) was prepared by a chemical polymerization method in a medium of ammonium persulfate as an oxidant and characterized by employing Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and Ultra-violet (UV) spectroscopy. The purified enzyme was entrapped in the biocomposite matrix film with the aid of a glutaraldehyde cross-linking reagent to establish the immobilization of the lipase. The principle of the biosensor is based on the electrochemical properties of amlodipine besylate (AMD), which were studied for the first time using the cyclic voltammetric method. The cathodic behavior of AMD was measured on the irreversible reduction signal at −0.185 V versus Ag/AgCl at pH 7.4 and 30 • C in a phosphate alkaline buffer.

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Purpose A new electrochemical analysis based on ß-cyclodextrin (ß-CD) was developed for penicillin V (Peni-V) using polyaniline as a conducting polymer. Design/methodology/approach The preparation of modified electrode involves the incorporation of β-CD with membrane of polyaniline. Polyaniline, incorporating β-CD, was prepared by electrochemical polymerization method in a medium of hypochloride. Cyclic voltammetry and electrochemical impedance have been used to characterize this sensor. The detection and the kinetic study of modified platinum electrode are evaluated. Findings Results clearly indicate that β-CDs interfere with the polymerization mechanism with an inhibition factor. The inclusion phenomenon of β-CDs has been studied and applied to detect Peni-V. The principle of this electrochemical sensor is based on the chemical properties of β-CD, which were studied using the cyclic voltammetric method and impedance spectroscopy. The electrochemical behavior of Peni-V at concentrations between 10–8 and 10–2 M was measured versus Ag/AgCl at pH 7.4 and 30°C in a phosphate alkaline buffer. Relationship of Peni-V concentration in logarithmic mathematical form with current in potentiometric method and with resistance in impedimetric method were obtained. Originality/value The present study showed that the Pt electrode modified with Polyaniline–β-CD was an excellent candidate for sensitive penicillin analysis. The proposed electroanalytical technique is rapid, simple and inexpensive.

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Purpose The purpose of this paper is to study the immobilization of porcine pancreatic lipase (PPL), in an organic matrix by a covalent cross-linking method to sense propylparaben (PP) present in aqueous solution. Design/methodology/approach PPL immobilization was performed by the covalent cross-linking method, using bovine serum albumin (BSA) in the presence of saturated glutaraldehyde vapor (GA). The preparation of the enzymatic membrane involves the incorporation of porcine pancreatic lipase (PPL), bovine serum albumin (BSA) and glycerol into a phosphate buffer solution (PBS). Characterization of this sensor was performed by impedance spectroscopy (EIS) and scanning electron microscope (SEM). The effect of experimental conditions such as PPL activity, potential, scan rate, PP concentration, pH and presence of interfering elements were studied by cyclic voltammetry. Findings Under the optimal experimental conditions, a number of significant factors were optimized. The method exhibited good linearity in the range of 10–14 to 10–9 mol/L with a good correlation coefficient of 0.957, detection limit (LOD) of 3.66 × 10–15 mol/L and high sensitivity of 1.086 mA mol−1L. The authors also obtained a very good coverage rate of the surface equal to 91.44%, and hydrolytic activity of lipase is evaluated to 26.64 mmol min−1. The stability and the interference were also evaluated. The equivalent circuit used to explain the electrochemical behavior of modified electrode is a Randle circuit. Practical implications The main application of biosensors is the detection of biomolecules that are either indicators of a disease. For example, electrochemical biosensing techniques can be used as clinical tools to detect breast tumors, because these compounds (PP) were found in breast tumors. Originality/value The result registered in this paper indicates that the developed sensor is an efficient, fast, simple and inexpensive analytical tool that can be used for the analysis of water containing PP.