The quantitative determination of potassium as the tetraphenylboron salt

Abstract

Published procedures for the determination of potassium as the tetraphenylboron salt have been critically examined. It has been shown that quantitative precipitation of the potassium salt in a readily filterable form is made preferably from solutions in which the total acidity is greater than about 0.2 N . Solutions of acidity up to 0.66 N have been employed at a temperature of 0°C.When the determination is made at room temperature, high results may be obtained owing to contamination of the precipitate by decomposition products of the tetraphenylboron. This is completely prevented by carrying out the determination a t a temperature of 0" C. Under such conditions accurate results have been obtained on potassium in amounts up to 25 mg.The method has been applied to the determination of potassium in solutions containing a wide range of commonly occurring ions. Thus, in addition to its simplicity, it is considered to be more specific than the well known alternative procedures. * This acidity is less than that employed in the experimental work described on pp. 350 and 351. There appeared to be no advantage in using an acidity much greater than the minimum value required to give good filtration. It is sufficiently high to prevent co-precipitation of impurities, such as iron, when present.

Gravimetric Determination of Chlorhexidine Using Tetraphenylborate Ion

“…The effect of acidity on the stability of tetraphenylborate and on the filtration properties of tetraphenylborate salts was tested by other workers (14)(15)(16)(17), and published information often contained contradictory statements on the optimum conditions for the precipitation. In general, the precipitate formed under alkaline conditions is poorly filterable; however, excessive acidity promotes decomposition of the precipitant (18).…”

Reactions of nitrosyl chloride with some transition metal-cyano complexes in selected nonaqueous media

“…Analytical Procedures.-The potassium content of the various starting materials and products was determined gravimetrically by precipitation as the tetraphenylborate from acidic solution. 13 Potassium-containing materials which were water insoluble were prepared for analysis by decomposing them in basic solution with calcium hypochlorite.14 The percentage of cyanide in a sample was determined by one of several methods. Where there apparently was no bridging cyanide present, the modified Kjeldahl procedure for nitrogen described by Jaselski and Lanese15 generally proved satisfactory.…”

Potassium-argon dating of basaltic rocks

“…Potassium is determined by the potassium tetraphenylboron (KTPB) gravimetric method, the flame photometric method, or both. The KTPB gravimetric technique is basically similar to that discussed by Sporek and Williams [1955]. The flame technique involves flame buffering without chemical separation and interpolation between similarly buffered standards (for some of the potassium-rich samples).…”