KINETICS AND MECHANISMS OF THE GRIESS REACTION

The kind and position of substituents on the aniline and naphthylamine reagents used in the Griess method of nitrite analysis were assayed, and the factors that control the rate, amount, and stability of the pigment formed from the reaction were defined. This work has shown that the Hammett relationship may be used to determine in part the utility of the aniline derivatives under the unique conditions of nitrite analysis. However, specific reagent combinations result in poor pigment production because of multiple reactions, multiple products, incomplete conversion, and pigment instability. Impediments to complete conversion of nitrite to diazo pigment include multiple nitrous acid reactions with both the aniline and naphthyiamine derivatives and instability of reaction intermediates. Other factors critical to pigment production, including pH, temperature, and concentration of reagents, both relative and absolute, were quantitated. Added reductants usually result in lessened pigment production, except with certain reagent combinations where the same or higher concentrations are produced. Criteria are given for establishing the utility of reagent combinations to be used for nitrite analysis. © 1979, American Chemical Society. All rights reserved.