Abstract

Coated graphite Gallium ion selective electrode was developed by depositing a membrane comprising of
Aliquat-336 loaded with Gallium in the form GaCl4- and poly vinyl chloride in the ratio of 70:30. Specific
properties of the electrodes were studied including calibration curve, slope, detection limit, concentration
range, response time and life time. The effect of chloride concentration was investigated. This coated graphite
Gallium ion selective electrode exhibits linear Nernstian response over gallium concentration range of 1x10-4M
-1x10-1M of Ga(III) ions in constant chloride concentration of 6M with a detection limit of 2x10-5 M calibration
slope of -58.2 mV ± 1.0 mV/decade change in concentration of Ga. Interference of Li+, Na+, K+, Ca2+, Mg2+,
Ba2+, Fe3+, Cr3+, Ni3+, Th4+, U(VI), OH-, CO32- and NO3- on electrode response have also been investigated.
The selectivity coefficients of this electrode with respect to the different ions were determined by matched
potential method. This coated graphite gallium ion selective electrode can be used for consecutive three months
without losing Nernstian response.