Sample stacking using field-amplified sample injection in capillary zone electrophoresis in the analysis of phenolic compounds

This paper discusses a simple on-column concentration with a field-amplified injection technique, using eleven US Environmental Protection Agency (EPA) priority phenols as model compounds. The capillary dimensions (length and internal diameter) for enhancing the on-column enrichment for phenolic compounds are studied. Under the proposed operational conditions, the detection limits (SIN=3) were in the ppb range, and the relative standard deviations for the compounds were between 1.4 and 8.8%. Field-amplified injections are preferred to off-line preconcentration methods because of their simplicity, rapidity and high enrichment factors. (C) 1997 Elsevier Science B.V.