[en] Ion chromatography is ideally suited for trace analysis of precipitation samples, because several ionic species at various concentrations can be analyzed simultaneously with little or no sample preparation. In the rain samples found in the rural, eastern United States, several species can be easily analyzed; however for trace analysis work, seven species (SO42-, NO3-, Cl-, PO43-, K+, NH4+, and Na+) are all that are easily separated, using the anion and cation columns