Abstract
The principle of rapid sulphate analysis commonly used in the limnology is the substitution of this ion with chromate ion. There are three methods to determine the chromate which is equivalent to the sulphate content in the sample.
1. Iodimetry, generally called Andrew's method. This is not at all usefull for a small amount of sulphate.
2. Colorimetry with the yellow colour of chromate ion. This is the most appropriate method, if the water contains from 20mg. to 1 gr. of sulphate ion per litre.
3. Colorimetry with diphenyl-carbazide.
The colour is not always proportional to the concentration of the chromate present.
