Effect of Concentration of Organic Modifier on Retention of Cation and Anions

Primesep 100 and Primesep B columns connected in series allow the quantitation of sodium chloride and potassium bromide ions in one injection. The Primesep B column retains the chloride and bromide anions by anion exchange, and the Primesep 100 retains the sodium and potassium cations by cation exchange. The retention can be adjusted by changing the water/acetonitrile ratio in the mobile phase. The separation uses a mobile phase mixture of water, acetonitrile (MeCN, ACN) and ammonium acetate with evaporative light scattering detection (ELSD).