ONLINE MICRODISTILLATION-BASED PRECONCENTRATION TECHNIQUE FOR AMMONIAMEASUREMENT

The development and optimisation of an on-line ammonia preconcentratio n system, based on a recently commercialised continuous flow microstil l, is described. The preconcentration system was integrated with a com puter-controlled flow injection system and an ammonia gas sensing prob e to form a complete potentiometric ammonia monitoring system, with a limit of detection of 5 mu g l(-1) NH3-N and a sample throughput of 10 samples per hour, Details of the optimisation process are presented, along with results of recovery experiments and selectivity data for so me commonly occurring interfering amines.