A selective and sensitive carbon composite coated platinum electrode for aluminium determination in pharmaceutical and mineral water samples

摘要

A novel coated wire electrode (CWE) for Al(III) ions is described based on 2-(1H-benzo[d]imidazole-1-yl)-1 -phenylethanoneoxime as a new ionophore in carbon-PVC composite. The sensor exhibits significantly enhanced selectivity toward Al~(3+) ions over the concentration range 4.3 x 10~(-7) to 5.0 x 10~(-2) M with a lower detection limit of 2.5 x 10~(-7) M and a Nernstian slope of 19.41 ± 0.52 mV decade~(-1) of aluminium activity. This sensor has a short response time of about 10s and is reproducible and stable for at least forty-five days. This proposed CWE which is designed for the first time revealed good selectivity for Al(III) over a wide variety of other cations. The performance of the sensor is best in the pH range of 3.1 -5.5 and it also works well in partially non-aqueous medium. Moreover, the assembly has been successfully used as an indicator electrode in the potentiometric titration of aluminium (III) against EDTA and also in determining Al(III) quantitatively in pharmaceutical and mineral water samples.