Ion chromatography in determination of ammonium ion in PM_2.5

ObjectiveTo evaluate an ion chromatography method for the determination of ammonium ion in ambient air particulate matter (PM_2.5).

MethodsThe samples of ambient air particles (PM_2.5) were collected from the silica fiber filter membrane.The ammonium ions were extracted by ultrasonic extraction and the content of ammonium ions in the samples was tested by ion chromatography.An inhibitory conductivity detector, CS16 cation analysis column and 20% methanesulfonic acid as the fluent were selected for determination.The relative retention time was qualitatively determined and the peak area quantified.Uncertainty was used in the determination of ammonium ion content.

ResultsThe ammonium ion was in the range of 0-50 mg/L (r=0.9997).The precision of the method was high (RSD 0%-0.51%).The detection limit was 0.13 mg/L and the lower limit 0.52 mg/L.

ConclusionIon chromatography method is easy to operate without the influence of interfering ions, and can be used in special investigation of health influence on population threatened by the national air pollution (fog haze).