A simple,rapid and reliable gas-diffusion flow injection(GD-FI) method for ammonium determination in
building materialshasbeendeveloped.Itisbasedonleachingammoniumfromagroundsolidsampleinto
an alkalinesolutionwithsubsequentammoniagasgeneration.Ammoniaisthentransportedinanitrogen
streamtotheGDcelloftheFIsystemwhereitisabsorbedintoitsacceptorsolutioncontainingamixtureof
theacid–base indicatorscresolredandthymolblue.Themaximumincreaseintheabsorbanceofthe
acceptorsolutionat580nmisrelatedtotheammoniumconcentrationinthesolidsample.Theproposed
methodischaracterizedbyalinearconcentrationrangeof0.1–5.0 mg NH4 + kg1, alimitofdetectionof
8 μg NH4 + kg1 andasamplethroughputof10h1. Asuccessfulapplicationofthismethodforthedeter-
minationofammoniuminbuildingmaterialssuchasconcrete,cementandsandisreported.