A Critical Study on the Methods of Water Analysis. (VII)

[摘要] In the previous paper, the author described the result of some experiments about the sulphate determination of water, and he found a direct colorimetric method by the yellow colour of chromate was most useful for 20mg. SO4 per litre or more. The nephelometric determination has been studied here, for more minute quantity of sulphate. Reagents: A. 12 gr. NaCl, 2 gr. BaCl2 2H2O. 4gr. gelatin in 100cc. solution. B. 0.6N HCl. Procedure: to 50cc. of water, add 1 cc. of B and 2cc. of A, and mix well. The turbidity due to barium sulphate suspension is compared with that of the standard nephelometricaily.Results: this method is suitable for the sulphate ion from 3mg. to 25mg. per litre.

[学科分类] 大气科学