Room temperature ionic liquids (RTILs), 1-n-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF 4 , and multiwalled carbon nanotubes (MWCNTs) were used for improvement of a praseodymium carbon paste ion selective sensor response.[bmim]BF 4 can be a better binder than mineral oils. MWCNTs have a good conductivity which helps the transduction of the signal in carbon paste electrode. The characteristics of these electrodes as potentiometric sensors were evaluated and compared with PVC membrane sensor. The results indicate that potentiometric sensor constructed with ionic liquid shows an increase in performance in terms of Nernstian slope, selectivity, response time, and response stability compared to Pr(III) PVC membrane sensor.
This work describes the incorporation of ordered mesoporous carbon (OMC) as a sensing material for carvedilol (CAR) detection on a glassy carbon electrode (GCE).
The aim of this study involves the determination of mercury ions at nanomolar level with the employment of the dipyridyl functionalized nanoporous silica gel -chemically modified carbon paste electrode (DPSG-CPE) by anodic stripping voltammetry. The experiments were conducted with a certain electrode composition of 25% paraffin oil, 60% high purity graphite powder and 15% DPSG as well as the usage of 0.20 M KNO 3 as supporting medium. The reduction potential and time were set at, 200 mV and 450 s, respectively, and the scan rate at 100 mV s -1 in the scan range of 200 to 500 mV. The analytical performance of the modified electrode was evaluated with respect to the carbon paste composition, the solution pH at the accumulation step, the preconcentration time, the mercury concentration, the possible interferences and other variables. On this modified electrode, the anodic stripping voltammetric mercury determination at nanomolar level concentrations was successfully attempted. The resulting electrode demonstrated linear response across a wide mercury(II) concentration range (20-100 nM) with a detection limit value of 8 nM, on the basis of a signal to noise ratio of 3. The precision for six determinations (n=6) of 40 and 75 nM mercury(II) was 5.0% and 2.8% (relative standard deviation), respectively. After studying the influence of the potential interfering ions, it was found that the proposed procedure was free from most interference. To testify the accuracy of this method, comparative determination of mercury(II) in wastewater samples by the proposed method and cold vapor AAS method were done and a sufficient sensitivity for the practical analysis of the environmental samples was attained.
This research introduces the design of an adsorptive stripping voltammetric method for the cerium(III) determination at a carbon paste electrode, chemically modified with dipyridyl-functionalized nanoporous silica gel (DPNSG-CPE). The electroanalytical procedure comprised two steps: the Ce(III) chemical accumulation at À 200 mV followed by the electrochemical detection of the Ce(III)/dipyridyl complex, using anodic stripping voltammetry. The factors, influencing the adsorptive stripping performance, were optimized including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The resulting electrode demonstrated a linear response over a wide range of Ce(III) concentration (1.0 -28 ng mL ). The precision for seven determinations of 4 and 10 ng mL À1 Ce(III) was 3.2% and 2.5% (relative standard deviation), respectively. The prepared electrode was used for the cerium determination in real samples and very good recovery results were obtained.
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