This procedure was developed primarily for analyses in which limited amounts of sample are available. Sodium and potassium can be separated from the other constituents of silicate rocks by cation exchange resin (Amberlite IR-120). The sample is decomposed with hydrofluoric and sulfuric acids and passed through the resin bed after expulsion of the fluorine. The column is eluted with 0.12N hydrochloric acid at a fast flow rate of 4 ml. per sq. cm. per minute and the sodium and potassium are recovered together within a reasonable time. Other constituents of the sample, except silica, can be determined on the same portion of sample.
Additional publication details
Use of ion exchange resins in the analysis of rocks and minerals: Separation of sodium and potassium