On the Determination of Nitrates in Potable Water.

Abstract

THE remark of Tiemann,1 that the estimation of no other substance has so constantly occupied the attention of the analytical chemists of the last decade, to the extent to which the determination of nitric acid has engaged (literally "enchained") them, will, I think, be appreciated by all those who have worked upon the subject. Perhaps no determination requires more care, or occasions more trouble in its execution, or is more unsatisfactory when finished, than the one in question.There are two general modes of procedure: a. The direct estimation, and b. The reduction to ammonia.a. DIRECT ESTIMATION.The direct processes which have been found to give the best results are those of Schulz-Tiemann,3 Schloesing-Reichardt,3 Crum-Lunge,4 and Marx-Tronnnsdorf.5 These are only applii Tiemann Gaertner "Wasseranalyse" 3rd. Ed'n,, p. 168. 2 Ber. d. chem Ges., 6, 1041.

Studies on the Phenoldisulfonic Acid Method for Determining Nitrates in Soils.

“…Lip man and Sharp,2 and Kelly7 call attention to great losses in the determination due to presence of sulfates either in the solutions, or when sulfates as potash alum are used as a flocculent. Chlorides seem to be the greatest interfering salt as evidenced by the investigations of Gill,12 Stewart and Greaves,10 and Chamot and Pratt.4 The latter investigators also point out the interference of chloroform when used in soil solution to prevent denitrification. They also show that the presence of iron produces a brown or red solution, thus affecting the desired yellow color of the nitrophenoldisulfonate.…”