[5] This proceeds via phenylsulfamic acid; a zwitterion with a N-S bond.

[6][7] Subsequent radiosulphur studies showed that the process is intermolecular, with the phenylsulfamic acid desulfating to generate sulfur trioxide, which then reacts with aniline at the para position in manner similar to a Bamberger rearrangement.

[4] This property is also used for the quantitative analysis of nitrate and nitrite ions by diazonium coupling reaction with N-(1-Naphthyl)ethylenediamine, resulting in an azo dye, and the concentration of nitrate or nitrite ions were deduced from the color intensity of the resulting red solution by colorimetry.

[10] It is also used as a standard in combustion analysis and in the Pauly reaction.

Reflecting its wide use, sulfanilic acid is found in the leachates of landfills.