Application of isotachophoresis in commercial capillary electrophoresis instrument using C(4) D and UV detection.

In this work, we tested the applicability of a commercial CE instrument (Agilent) for capillary ITP (CITP). The fused silica capillaries were flushed with PVP solution before each sample injection to suppress the EOF. As a dual-detection mode, commercial capacitively coupled contactless conductivity detection and ultraviolet detectors were applied. The experiments showed that the detection gap of the capacitively coupled contactless conductivity detection limits the achievable LOD and the separation resolution when the analyte CITP zones are very narrow, therefore long (120 cm) CE capillary was used and it was largely filled with the sample solution. CITP analyses of several real samples (leather extract, red wine, juice, and fizzy drink) have been demonstrated. In peak mode of CITP when the zone of a chromophore analyte is positioned between nonchromophore zones, excellent sensitivity (in submicromolar concentration range) could be achieved by ultraviolet detection. The hazardous chromate in low concentration was determined in the aqueous extract of tanned leather.