The Use of Contactless Conductivity for the On-Column Characterisation and Visualisation of Packing Homogeneity and Band Broadening in Capillary LC

Capacitively coupled contactless conductivity is presented as a simple non-invasive tool for the visualisation and evaluation of the axial homogeneity of packing density in capillary LC columns. Irregularities in frit structure and gross column voids were readily identified, the latter of which was confirmed with digital photography. Relative homogeneity of packing density was compared for two packed columns by measuring the variation in conductive response per unit length and varied from 1.1 to 4.2%. The on-column scanning methodology was applied to real-time visualisation of in-situ buffering effects arising from a packed poly-iminodiacetic acid bonded resin. Finally, the scanning detection technique was applied to the pre-elution visualisation of on-column band broadening.