Sol-gel column technology for capillary isoelectric focusing of microorganisms and biopolymers with UV or fluorometric detection.

The sol-gel surface modification is used for capillary isoelectric focusing of microorganisms and biopolymers. The coating strongly decreases the electroosmotic flow so that it enables the use of the short capillaries down to 100 mm in the separation length. The examples of capillary isoelectric focusing of the low-molecular-mass pI markers and mixed cultures of microbial populations of Escherichia coli, Candida albicans, Staphylococcus epidermidis, and Enteroccocus faecalis with UV detection are shown. It is possible to quantify bacterial cells according to their peak areas; the minimum detectable number of microbial cells was 5 x 10(2)-1 x 10(3). The compatibility of sol-gel capillaries with sensitive fluorometric detection of fluorescent pI markers together with fluorescein labeled proteins is demonstrated.