The alpha-naphthylamine-sulphanilic acid test is widely employed for the detection of reduction of nitrates to nitrites by bacteria. The test has the disadvantage that the reel coloration produced in the presence of the nitrite ion appears for only a few seconds and then fades in cultures of organisms in which a relatively high concentration of nitrite occurs. Frequently in our work it is necessary to test considerable numbers of cultures at one time. Fading makes the results unreliable and cultures having a relatively high concentration of nitrite may be recorded as negative. A second difficulty experienced with the test is the instability of the alpha-naphthylamine solution, resulting in its marked discoloration. When added to the culture, the discolored solution imparts a pink color which may prove confusing when testing cultures having relatively little nitrite present.
Proceedings of the Iowa Academy of Science
©1930 Iowa Academy of Science, Inc.
Werkman, C. H.
"Dimethyl-Alpha-Naphthylamine for the Determination of Bacterial Reduction of Nitrates,"
Proceedings of the Iowa Academy of Science, 37(1), 53-55.
Available at: https://scholarworks.uni.edu/pias/vol37/iss1/7