Enhancement of Zirconium Atomic Absorption by Nitrogen-Containing Compounds and its Use in the Determination of Ammonia

The absorption by zirconium atoms in the nitrous oxide-acetylene flame is enhanced in the presence of many nitrogen-containing compounds which can act as Lewis bases. For ammonia the magnitude of this enhancement is proportional to the concentration of base over the range 1 × 10⁻⁴ to 5 × 10⁻³M and can be used to determine ammonia in the absence of phosphate and of certain nitrogen-containing compounds. When interfering species are present the method can be used, after prior distillation of the ammonia, to replace spectrophotometric methods which require considerable time for color development. The analytical usefulness of the enhancement technique is demonstrated by the determination of ammonia in biological systems.