Ion interaction chromatography of anions in alkaline solutions: effect of temperature and the kind of stationary phase

Effect of temperature (5°–65°C) on the separation of 11 inorganic anions by ion interaction chromatography (IIC) was studied employing RP C₁₈ and C _PhenylHexyl columns and aqueous mobile phase: 2.8 mM NaHCO₃ + 0.7 mM TBAOH (tetra-n-butylammonium hydroxide). The apparent enthalpy changes, ΔH for hydrophobic ions like I^?, SCN^?, and ClO₄ ^? largely exceeded 3 kcal/mole suggesting that added to ion exchange they are retained by hydrophobic adsorption. Unlike conventional strongly basic anion exchangers, our system can be used at elevated temperatures with alkaline eluents without irreversible damaging the column.