Constant-current potentiometric titration of orthophosphate with cetylpyridinium chloride: a feasibility study.
The feasibility of constant-current potentiometric titration of orthophosphate with cetylpyridinium chloride has been studied. The phosphate solution is acidified with hydrochloric acid to pH 1.1-1.3 and an excess of molybdate solution added. For l mg of phosphorus (as phosphate) the optimum Mo:P ratio is about 40. Cetylpyridinium chloride reacts stoichiometrically with 12-molybdophosphate, in 3:1 ratio. The optimum cathodic polarizing current is 1.1 muA. The blanks for molybdate are relatively small, constant and non-stoichiometric.
Selig
W
W
Lawrence Livennore National Laboratory, University of California, Livermore, California 94550, U.S.A.