Fluorogenic reaction and specific microdetermination of ammonia.

The fluorogenic reaction of ammonia with omicron-phthalaldehyde (OPT) and dithiothreitol (DTT) is reported. Optimal detection wavelengths are lambda ex = 413 nm and lambda em = 476 nm. This fluorescence is specific for ammonia: other amino compounds, such as amino acids, amines and proteins, do not show emission at 476 nm when activated at 413 nm. This reaction permits specific microdetermination of ammonia in biological materials down to the nanomole range.