On-line Microdistillation-based Preconcentration Technique for Ammonia Measurement

Abstract

The development and optimisation of an on-line ammonia preconcentration system, based on a recently commercialised continuous flow microstill, is described. The preconcentration system was integrated with a computer-controlled flow injection system and an ammonia gas sensing probe to form a complete potentiometric ammonia monitoring system, with a limit of detection of 5 µg 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 some commonly occurring interfering amines.