Retention modelling of ion chromatography for cations in atmospheric aerosols

Abstract

Concentrations of six water-soluble cations (lithium, sodium, ammonium, potassium, magnesium and calcium) in atmospheric aerosol samples, collected in a suburb of Belgrade (Serbia), were determined by ion chromatography (IC). In order to obtain a better separation, interpretive retention modeling was employed to optimize the isocratic ion chromatographic (IC) separation with the methanesulfonic acid (MSA) eluent. The influence of wide variations of the MSA concentration (5-45 mM) on the IC separation was studied. The quadratic model shows a very good prediction power. For the most optimal conditions in the experimental design, the global resolution was optimized. The eluent concentration of 18 mM of MSA was found to be an optimum for cations separation on a Dionex CS12 column with the total analysis time of less than 10 minutes. Time-series analysis strongly suggests that concentrations of cations in aerosol samples are affected by mineral dust from both natural and anthropogenic sources.