The chemistry of Heller’s test for urine Indican detection

The Heller’s color test for indican in urine is interesting because besides detecting this important biomarker it reveals the dual function of nitric acid since can accomplish synthesis indigo blue and red, as well degrade them to isatin, depending upon reaction conditions. Moreover, inspired other tests detection, using oxidizing reagents. Actually, detected by a colour chart with different tones indicating concentration via formation. In paper we provide series reactions that occur during test, there are nitrations followed redox reactions. organic intermediates oxidized inorganic reagent reduced nitrous acid. However, red be degraded on .heating. electron flow given each step.