8-quinolinol-5-sulphonic acid as both indicator and masking agent--II: titration of phosphate with La(III).
The use of 8-quinolinol-5-sulphonic acid as both masking agent and indicator in the titration of phosphate with La(III) has been investigated. The reagent forms complexes with most cations in preference to the formation of their phosphate precipitates at pH 7, but the reverse is the case for the rare earths, which permits the precipitation reaction to be carried out in the presence of these other cations. Amounts of P of the order of 5 microg have been determined at a concentration of 5 ppm.
Bishop
J A
JA
Cedar Crest College, Allentown, PA 18104, USA.
Soler
J
J