New methods for the detection of carboxylic acid groups in organic compounds, with acriflavine.
The dye acriflavine is used for the selective detection of the carboxylic acid group in organic compounds. Two simple, rapid, and reliable colour tests are reported; these are based on the development of a violet colour and a yellow to yellowish-brown precipitate when a carboxylic acid is treated with acriflavine/sodium nitrite and acriflavine/potassium chromate respectively. Other acidic compounds such as phenols, thiophenols, sulphinic acids, sulphonamides, and acid imides do not interfere. Sulphonic acids (with the exception of their amino derivatives) interfere with both the tests. Enols and salts of organic bases do not interfere in the former test, whereas they do interfere in the latter test. The probable nature of the reaction products in both the tests has been discussed. Based on the former reaction, a procedure is described for the selective detection of nitrite ion. The limit of detection is 25 mug of nitrite per ml. Only iodide interferes.
Johar
G S
GS
Department of Chemistry V.S.S.D. College Kanpur, India.
Agarwala
U
U
Sodhi
H S
HS