Potentiometric Determination of HPO42- with Chitosan-glutaraldehyde by Carbon Paste Electrode

In this article a selectivity potentiometric methodology, using an ion-selective electrode, for determination of HPO42- anion in aqueous solution was investigated. Chitosan- glutaraldehyde complexes is used. A room temperature ionic liquid, 3-methyl-imidazolium tetrafluoroborate and paraffin for compare of conductive effect are used. Response time, pH range, electrode selectivity, electrode life have been investigated. Carbon nanotubes (WCNTs) were used in the composition of the carbon paste to improve conductivity and transduction of chemical signal to electrical signal. Also, the effect of different carbon nanotubes (single-wall carbon nanotubes, multi-wall carbon nanotubes and COOH functionalized single-wall carbon nanotubes, COOH functionalized multi-wall carbon nanotubes and NH2 functionalized single-wall carbon nanotubes and NH2 functionalized multi-wall carbon nanotubes) on the electrode s response has been investigated. The electrode has a short response time (∼5 s) and can be used for at least 60 days without any considerable divergence in potentials, and the working pH range was 6.5–8.5. fabricated sensor for determining of HPO42- demonstrated a maximum Nernstian slope equal to 30.06 mVdecade-1 along a linear range from 1×10−5 to 1×10−2 mol.L−1 and detection limit of 8.55×10−5 mol.L-1. Finally, the proposed electrode was successfully used as an indicator for potentiometric determination of HPO42- in Hydroponic farm wastewater samples.