A new liquid-membrane electrode for selective determination of perchlorate.
A new liquid-membrane electrode which responds to perchlorate ion is described. It incorporates a 10(-2)M solution of the nitron-perchlorate ion-pair complex, in nitrobenzene, as a liquid membrane. The electrode exhibits near-Nernstian response for 10(-2)-2 x 10(-5)M perchlorate with an anionic slope of 56 mV pClO (4)). The response time is 20-90 sec, the working pH 2.5-8.5, the lower limit of detection 8 x 10(-6)M perchlorate and the selectivity for perchlorate relative to 27 inorganic and organic anions of different nature is reasonably high. Periodate, permanganate and thiocyanate, however, interfere. Determination of 2-1000 microg ml perchlorate in aqueous solutions shows an average recovery of 98.8% and a mean relative standard deviation of 1.9%. The electrode has been successfully used for direct potentiometric determination of the purity of perchlorate propellants and the solubility products of some sparingly soluble perchlorates.
Hassan
S S
SS
Department of Chemistry, Faculty of Science, Ain Shams University, Cairo, Egypt.
Elsaied
M M
MM