Determination of Potassium and Sodium in Borates by Differential Flame Photometry

Differential flame photometry was applied to the determination of potassium and sodium in borates,and accurate results were obtained in the range of 0-100 mg·L-1 for potassium and in the range of 0-200 mg·L-1 for sodium.Interference of boron to the determination of potassium and sodium and also the mutual interference of co-existence of potassium and sodium were studied thoroughly.In comparing with the sodium tetraphenylboron gravimetric method of National Standard,results of potassium obtained by the proposed method were all lower with absolute value of relative deviation ≤3.91%,but no significant difference was found between these two methods as tested by both the t-testing and F-testing.When compared with the AAS method,absolute values of relative deviation found for potassium was ≤3.63%,and for sodium was ≤3.76%,and also no significant differences were found between the present method and the AAS method as shown by the results of both the t-testing and F-testing.Test for recovery by the standard addition method was performed and results obtained were in the ranges of 97.5%-102.5% and 97.1%-99.1% for potassium and sodium respectively.