Chloride voltammetric Sensor Based On Aminated Carbon Nanoparticles

Nano-carbon based electrodes e.g. based on carbon nanotubes, carbon nanofibers, graphene, orcarbon nanoparticles are of interest in electrochemical processes due to their often highly activesurface characteristics and their ease of functionalisation. The modification of functional groupsat carbon surfaces provides an important tool for achieving chemical selectivity [1]. Chloride ionconcentration is an important parameter for various biological and environmental applications.Chloride is a key parameter of water quality and salinity. In mechanical industries chloride is amajor contributor to corrosion of metal components in steam-generating systems. Chloride is alsoone of the major contributors to reinforcement corrosion in concrete, especially for structuresnear sea water or which are exposed to deicing salt. The chloride ion concentration inside thereinforced concrete has been linked to the corrosion process and it is therefore highly desirable tobe able to detect the chloride ion concentration level. Thus, keeping in view these applications,the development of a long-term and reliable chloride ion sensor is of great importance [2]. In thisstudy, the surface functionalized aminated carbon nanoparticles have been prepared andcharacterized. A novel, inexpensive, highly simple, and disposable sensor for the determinationof chloride ions has been developed. It is based on the systematic shift of the voltammetric peakpotential of a Hg(ΙΙ) species in presence of chloride ions. Differential pulse voltammetry has beenapplied for sensitive determination of chloride ions in real samples. The disposable character andsimplicity of the device provides an interesting alternative to the most frequently usedpotentiometric method.MethodsVoltammetric experiments were performed using a Metrohm Computrace VoltammetricAnalyzer model 797 VA. A conventional three-electrode. The modification of glassy carbon electrode has been performed by casting method. The modified electrode has been used forvoltammetric measurements.Results and DiscussionMorphology and structure of the resultant product were characterized by SEM, FT-IRspectroscopy and electrochemical techniques (Electrochemical Impedance Spectroscopy andcyclic voltametry). It was observed that the voltammetric peak of a Hg(ΙΙ) species at the surfaceof GCE/ CNP-NH2 electrode shifts when chloride is added to the sample. The systematic shift ofthe peak potential of a Hg(ΙΙ) is related to the amount of chloride. The potential shift increasewith chloride concentration from 10-7 M to 0.1 M, and a linear relationship between peakpotential and the logarithm of chloride concentration was obtained in this concentration range(figure 1). ConclusionThe covalently modification of carbon nanoparticles with ethylene diamine functional groups isdemonstrated. The new carbon nanoparticle substrate is versatile and can be employed forsensitive and selective determination of chloride ions. Nowadays, the development of alternativemethods for chloride determination in waters is very interesting due to the problems associated topotentiometric methods, generally used in routine determinations. This work describes thesuccessful development of a low cost method for the detection of chloride ion, which is based on the shift measurement of voltammetric peak potential of mercury, when this ion is present in asolution.

کلیدواژه ها:

Carbon Nanoparticle ، Covalenty Modification ، Voltametry Sensor ، Chloride