Anoop Raj Singh Rana

Electrochemical sensor for the sensitive determination of norfloxacin in human urine and pharmaceuticals

Electrochemical determination of Norfloxacin (NF) has been presented at edge plane (EPPGS) and basal plane pyrolytic graphite sensors (BPPGS) by using square wave voltammetry at physiological pH 7.2. An increased peak current with a shift of peak potential to less positive value was observed at EPPGS as compared to BPPGS. The effect of pH, scan rate and analyte concentration has been examined. The peak current was found to be linear to the concentration of NF in the range 0.5 × 10(-6) to 50.0 × 10(-6)mol L(-1) for EPPGS and the detection limit (3σ/b) was found to be 28.3 × 10(-8)mol L(-1). The method has been successfully used to determine the content of NF in the pharmaceutical preparations. Biological relevance of the developed method has been described by the determination of NF in human urine samples of the patients undergoing treatment with NF. The method is selective and NF can be determined without any interference from common urine metabolites such as uric acid and ascorbic acid.

Effect of gold nanoparticle attached multi-walled carbon nanotube-layered indium tin oxide in monitoring the effect of paracetamol on the release of epinephrine.

A gold nanoparticle attached multi-walled carbon nanotube-layered indium tin oxide (AuNP/MWNT/ITO) electrode has been used for monitoring the effect of paracetamol (PAR) on the release of epinephrine (EPI) in human urine. The modified electrode shows an excellent electrocatalytic activity for the oxidation of EPI and PAR with acceleration of electron transfer rate as compared to MWNT/ITO and AuNP/ITO. An apparent shift of the oxidative potential towards less positive potential with a marked increase in peak currents is observed in square wave voltammetry at AuNP/MWNT/ITO electrode. The calibration curves for the simultaneous determination of PAR and EPI showed an excellent linear response, ranging from 5.0×10(-9) mol L(-1) to 80.0×10(-9) mol L(-1) for both the compounds. The detection limits for the simultaneous determination of PAR and EPI were found to be 46×10(-10) mol L(-1) and 42×10(-10) mol L(-1) respectively. The proposed method has been successfully applied for the simultaneous determination of PAR and EPI in human urine. It is observed that gold nanoparticles attached with multi-wall carbon nanotube catalyze the oxidation of EPI and PAR.

A comparison of edge- and basal-plane pyrolytic graphite electrodes towards the sensitive determination of hydrocortisone

Electrochemical sensor employing edge-plane pyrolytic graphite electrode (EPPGE) for the sensitive detection of hydrocortisone (HC) is delineated for the first time. The electrochemical properties are investigated exercising the cyclic voltammetry and square-wave voltammetry (SWV). When equating with the bare basal-plane pyrolytic graphite electrode (BPPGE), the EPPGE gave better response towards the detection of HC both in terms of sensitivity and detection limit. The voltammetric results indicated that EPPGE remarkably enhances the reduction of HC which leads to considerable amelioration of peak current with shift of peak potential to less negative values. The difference in the surface morphology of two electrodes has been studied. Also, the EPPGE delivered an analytical performance for HC with a sensitivity of 45 nA nM(-1) and limit of detection of 88 nM in the concentration range 100-2000 nM. The method has been utilized for the determination of HC in pharmaceuticals and real samples. The electroanalytical method using EPPGE is the most sensitive method for determination of HC with lowest limit of detection to date. The major metabolites present in blood plasma did not intervene with the present investigation as they did not exhibit reduction peak in the experimental range used. A comparison of results with high performance liquid chromatography (HPLC) signalizes a good agreement.

A single-wall carbon nanotubes modified edge plane pyrolytic graphite sensor for determination of methylprednisolone in biological fluids.

An electrochemical protocol based on reduction is developed to determine methylprednisolone using single-wall carbon nanotubes (SWNTs) modified edge plane pyrolytic graphite electrode (EPPGE). To obtain a good sensitivity, instrumental variables were studied using Square Wave Voltammetry (SWV). The voltammetric results indicate that SWNTs modified EPPGE remarkably enhances the reduction of methylprednisolone which leads to considerable improvement of peak current with shift of peak potential to less negative values. The voltammetric current showed a linear response for methylprednisolone concentration in the range 5-500 nM with a sensitivity of 98 nA nM(-1). The limit of detection was estimated to be 4.5x10(-9)M. The developed method is used for the determination of methylprednisolone in pharmaceutical dosages and human blood plasma samples of patients undergoing treatment with methylprednisolone. The major metabolites present in blood plasma did not interfere with the present investigation as they did not exhibit reduction peak in the experimental range used. A comparison of results with high performance liquid chromatography (HPLC) indicates a good agreement.

A sensitive voltammetric sensor for detecting betamethasone in biological fluids.

A rapid and sensitive voltammetric sensor based on reduction of betamethasone has been developed using single wall carbon nanotube modified edge plane pyrolytic graphite electrode (SWNT/EPPGE). The reduction of betamethasone occurred in a well-defined, pH dependent peak. Linear calibration curve was obtained in the range 1 to 25 nM in 1.0 M phosphate buffer solution (PBS) of pH 7.2 with the limit of detection (3sigma / slope) as 0.50 nM. The analytical utility of the developed method has been demonstarted by sensing the drug in human body fluids and for the determination of betamethasone content in several commercially available pharmaceutical preparations. Interfering effect of some common metabolites including ascorbic acid, uric acid, albumin and hypoxanthine has also been evaluated. A comparison of the observed results of proposed method with HPLC clearly indicates that the results of both methods are essentially similar.