We use a Dionex ICS 2000 to separate and quantify the relative proportions of anions in aqueous samples. Our system is equipped with an IonPac AS18 column and KOH eluent that can easily analyze common anions including fluoride, chloride, nitrite, nitrate, bromide, sulfate and phosphate and can be calibrated for other anions upon request.
Principles of Ion Chromatography
Ion-exchange chromatography retains molecules on a column based on ionic interactions. Anions are retained by a column with a stationary phase displaying positively-charged functional groups. The target anions are eluted from the stationary phase by increasing the concentration of the negatively-charged species (OH–). Analytes are then quantified sequentially as peaks with specific retention times using a conductivity detector.