Determination of common inorganic anions and cations by non-suppressed ion chromatography with column switching

An ion chromatography (IC) method has been proposed for the determination of seven common inorganic anions (F-, H2PO4-, NO2-, Cl-, Br-, NO3-, and SO42-) and/or five common inorganic cations (Na+, NH4+, K+, Mg2+, and Ca2+)using a single pump, a single eluent and a single detector. The present system used cation-exchange and anion-exchange columns connected in series via a single 10-port switching valve. The 10-port valve was switched for the separation of either cations or anions in a single chromatographic run. When 1.0 mM trimellitic acid (pH 2.94) was used as the eluent, the seven anions and the five cations could be separated on the anion-exchange column and the cation-exchange column, respectively. The elution order was found to be F- < H2PO4- < NO2- < Cl- < Br- < NO3- < SO42- for the anions and Na+ < NH4+ < K+ < Mg2+