Griess reagent is a mixture of two solutions:
1) A solution of sulfanilic acid in hydrochloric acid
2) A solution of N-(1-naphthyl)-ethylenediamine dihydrochloride in water.
When Griess reagent is added to a solution containing nitrite ions, a red-violet azo dye is formed. The intensity of the color is proportional to the concentration of nitrite ions in the solution.
The following steps can be followed to confirm the presence of nitrite ions in brinjal using Griess reagent:
1) Crush a small piece of brinjal and add it to a test tube containing 10 mL of distilled water.
2) Add 1 mL of Griess reagent to the test tube and mix well.
3) Observe the color of the solution. If a red-violet color develops, it indicates the presence of nitrite ions in brinjal.
Note: The presence of nitrite ions in brinjal may indicate that the vegetable has been treated with nitrogen fertilizers or that it has been contaminated with bacteria.
