Search

This paper describes the development of 1-methyl-3-butylimidazolium chloride ionic liquid/cobalt hexacyanoferrate nanoparticle modified multi-walled carbon nanotubes nanocomposite paste electrode for the electrocatalytic and adsorptive stripping voltammetric and impedimetric determination of diclofenac (DIC) in real samples. The nanocomposite was prepared by a simple chemical method and was characterised by scanning electron microscopy, Fourier transform infrared spectroscopy and atomic absorption spectroscopy. Also, the electrochemical behaviours of the modified electrode and the electrocatalytic oxidation of DIC were investigated in detail by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques. The kinetic parameters such as electron transfer coefficient, and apparent rate constant for the redox reaction between DIC and the modified electrode were also determined using electrochemical approaches. It was found that the modified electrode exhibited excellent electrocatalytic activity toward the oxidation of DIC, and under the optimised conditions, the linear response range and detection limit were found to be 1.0–100.0 and 0.3 μM, respectively using the differential pulse voltammetry method. The proposed method was applied for the sensitive and selective determination of diclofenac in the urine samples and pharmaceutical formulations with satisfactory results. [ABSTRACT FROM AUTHOR]

A new method for determination of methyldopa in the presence of folic acid has been described in this work. This method is based on modification of carbon paste electrode with NiO nanoparticles and an ionic liquid (1-Butyl-3-methylimidazolium hexafluorophosphate). Electrochemical studies showed that on the surface of modified electrode, oxidation current of methyldopa has been enhanced and shifted to negative potentials. The fabricated electrode exhibited a linear response to concentration of methyldopa from 0.1 to 700.0 μmol L −1 . The sensitivity of the modified electrode to methyldopa not changed in the presence of folic acid and simultaneous or independent measurements of them are possible. The performance of proposed method was investigated by determination of methyldopa in real samples. [ABSTRACT FROM AUTHOR]

Using a NiO/functional single walled carbon nanotubes nanocomposite incorporated with ionic liquid (IL/NiO/CNT/CPE), we prepared a sensitive and selective sensor for determination of nalbuphine (NA). Nalbuphine is a semi-synthetic analgesic drug. Electrochemical investigations showed that the nanocomposite had catalytic effect on oxidation of nalbuphine and enhanced the oxidation current. This modified electrode had linear dynamic range from 0.2 to 500.0 μmol L −1 NA with detection limit of 0.07 μmol L −1 NA. Selectivity of the sensor has been studied and proposed method has been applied for determination of nalbuphine in biological samples. [ABSTRACT FROM AUTHOR]

In the present work an easy-to-make and sensitive sensor based on ZnO nanoparticle (ZnO/NP) ionic liquid (IL) composite for voltammetric sensing of isoprenaline (ISN) in real samples was developed. The synthesized nanoparticle was characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The modified ZnO/NP ionic liquid carbon paste electrode (ZnO/NP/IL/CPE) was used as an electrochemical sensor for the determination of trace amounts of ISN. The anodic peaks of ISN and aspirin (ASP) in their mixture can be well separated. At pH 5.0 the two peaks are separated ca. 0.56 and 0.98 V, respectively; hence ISN can be determined in the presence of ASP and more than 2.6 times of the current excess of ISN. The square wave (SW) voltammogram peak current of ISN and ASP increased linearly with their concentration in the ranges of 0.3–320 μmol L − 1 ISN and 0.7–950 μmol L − 1 ASP. The detection limits for ISN and ASP were 0.09 and 0.3 μmol L − 1 , respectively. The suggestion sensor has been successfully applied for the assay of the above compounds in real samples such as drug and urine. [ABSTRACT FROM AUTHOR]

The direct electrochemistry of diclofenac (DCF) at a surface of modified carbon paste electrode (CPE) was described. The electrode was modified with multiwall carbon nanotubes (MWCNTs) and 1-butyl-3-methylimidazolium hexafluoro phosphate as a binder. The oxidation peak potential of the DCF at a surface of the ionic liquid carbon nanotubes paste electrode (IL/CNTPE) appeared at 750 mV that was about 70 mV lower than the oxidation peak potential at the surface of the traditional carbon paste electrode under similar condition. Under the optimized conditions at pH7.0, the peak current was linear to DCF concentrations over the concentration range of 0.3-750 µmol L-1, using square wave voltammetry (SWV). The detection limit was 0.09 µmol L-1. The proposed method was successfully applied to the determination of DCF in both pharmaceutical and patient urine samples. [ABSTRACT FROM AUTHOR]