Eluents sodium / -hydroxybenzoate

Fig. 3-5. Separation of various anions on PRP-X100. - Eluent 0.004 mol/L sodium p-hydroxybenzoate (pH 8.6) flow rate 3 mL/min detection direct conductivity injection volume 100 pL solute concentrations 20 ppm each (taken from [21]).

For non-suppressed ion chromatography to be successful, the ion exchanger used in the separation column must have a low exchange capacity and a very dilute eluent must be used. In the separation of anions, the resin must have an exchange capacity between about 0.005 mequiv/g and 0.10 mequiv/g. Typical eluents are 1.0 x 10 M solutions of sodium or potassium salts of benzoic acid, hydroxybenzoic acid, or phtha-lic acid. These eluents are sufficiently dilute that the background conductivity is quite... 

Evans et reported the HPLC-ED of plasma salicylate (2-hydroxybenzoate). A LoD of 4 ng on column was claimed. The eluent used was methanol-aq. sodium acetate (approximately 60mmolL pH 6.0) (4 - - 46). However, the column used was not stated, a protracted sample purification procedure was needed, no internal standard was used and the applied potential advocated (GCE, -I-1.35 V vs Ag/AgCl) was very high by comparison with other methods involving the ED of phenolic hydroxyl groups. 

Figure 3.17 Separation of various inorganic anions on LCA A03. Eluent 4mmol/L sodium p-hydroxybenzoate (pH 8.5) flow rate 2 ml7 min detection nonsuppressed conductivity ...

---