Oscillopolarographic adsorptive wave determination of microamounts of orthophosphate.
In the system HCl-Sb(III)-ammonium molybdate-acetone-butanone, PO(3-)(4), Sb(III) and Mo(VI) form a ternary heteropoly acid, which can be adsorbed on a dropping mercury electrode and reduced to a heteropoly blue. The electrochemical reaction produces a sensitive polarographic wave with peak potential of -0.42 V vs. SCE. The limit of determination of phosphate is 6 x 10(-8)M. The coefficients of variance are 10 and 3% for 0.1 and 1muM phosphate, respectively.
Chen
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Department of Chemistry, Jishou University, Hunan, People's Republic of China.