Published online by Cambridge University Press: 27 March 2009
The determination of sodium by Barber and Kolthoff's and Kahane's methods has been investigated with special reference to their suitability for the determination of exchangeable sodium in soils. Bray's modification of Barber and Kolthoff's method, involving 48 hours’ standing, was found to give a poor separation from even small amounts of potassium salts, leading to high results for sodium. Kahane's method was more convenient and gave very satisfactory results, precipitation being complete in 30 min. It is a great improvement on the older classical methods which involve the separation and weighing of sodium and potassium chlorides.