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

Different volatile carboxylic acids have been investigated as electronic co mpetitors to optimize the separation of 12 common anions (F-, H2PO4-, CL-, IO3-, IO4-, Br-, BrO3-, SO42-, C1O(3)(-), NO3-, I-, C1O(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 ef ficiency of the separation and the detector response. The retention of inor ganic anions on non-modified PGC is dominated by electronic interactions ba sed purely on donor-acceptor (charge transfer) interaction between the lone pair electrons of the solute and the pi-electrons of the PGC. (C) 1998 Els evier Science B.V. All rights reserved.