Determination of inorganic anions on porous graphitic carbon using evaporative light scattering detection: Use of carboxylic acids as electronic competitors

Abstract

Different volatile carboxylic acids have been investigated as electronic competitors to optimize the separation of 12 common anions (F −, H 2PO 4 −, Cl −, IO 3 −, IO 4 −, Br −, BrO 3 −, SO 4 2−, ClO 3 −, NO 3 −, I −, ClO 4 −) on a porous graphitic carbon (PGC) column with evaporative light scattering detection. The addition of pyridine in the aqueous acidic mobile phase improves the efficiency of the separation and the detector response. The retention of inorganic anions on non-modified PGC is dominated by electronic interactions based purely on donor–acceptor (charge transfer) interaction between the lone pair electrons of the solute and the π-electrons of the PGC.