Enhanced spectrophotometric determination of nicotinic acid in a sodium dodecyl sulphate micellar medium.

The spectrophotometric determination of pyridine and pyridine derivatives by means of the König reaction was studied in micellar media of sodium dodecyl sulphate (SDS), N-cetylpyridinium chloride and Triton X-100. The sensitivity was largely increased in SDS micellar medium. The attack of the pyridine ring with cyanogen bromide to produce a glutaconic aldehyde was not affected by the presence of SDS, but the yield of the coupling reaction with an arylamine to produce a polymethine dye was largely increased. In the SDS micellar medium, aniline was superior to other coupling reagents. The limits of detection (LODs) were 6 x 10(-7), 1 x 10(-6) and 5 x 10(-7)M for pyridine, pyrrol-ylmethylpyrid…