Single step on-column frit making for capillary high-performance liquid chromatography using sol-gel technology

One step frit-making in packing fused-silica capillary column of high-perfo rmance liquid chromatography was developed using sol-gel technology. Frit f abrication procedure was quite simple without sintering. On-column frit was formed through gelling of sol solution with packing materials, silica gel, and jointing the particles together with capillary wall through bonded and immobilized networks. Solvent types and proportions in sol solution were s elected. And the sol solution compositions as well as amount of silica gel particles were also optimized to achieve maximum strength. Such an on-colum n frit of 250 mum in diameter is capable of resistant packing pressure up t o 500 bars in ultra-sonic bath action. Chemical resistance to solvents and extreme pHs were also tested. Scanning electron micrograms of the frit prof ile showed that the evolving sol-gel network joined particles to each other and onto the column wall. Routine runs in reversed-phase mode, the frits o f several columns proved to be effective enough to resist pressures without collapse. (C) 2001 Elsevier Science B.V. All rights reserved.