Analysis of the performance of a flow reactor for use with microcolumn HPLC.

Postcolumn derivatization reactions can be used to improve detector sensitivity or selectivity. The advantages of capillary chromatography for trace analysis could be augmented if there were postcolumn reactors suitable for microchromatographic systems. However, postcolumn derivatization is a challenge because of the small peak volumes associated with capillary columns.

Simple method for the quantitative examination of extra column band broadening in microchromatographic systems.

In recent years capillary chromatography has gained popularity for trace analyses. Most often UV or electrochemical detection is employed because the small peak volumes make post-column derivatization challenging. We have developed a simple method based on flow injection for determining contributions to peak broadening from post-column reactors.

Fabrication of microchannel structures in fluorinated ethylene propylene.

A new technique for fabrication of channel structures with diameters down to 13 microm in fluorinated ethylene propylene (also known as poly(tetrafluoroethylene-co-hexafluoropropylene), FEP) is described. The technique is based on the unique property of a dual-layer fluoropolymer tubing consisting of an outer layer of poly(tetrafluoroethylene) (PTFE) and an inner layer of FEP. When heated (>350 degrees C), the outer PTFE layer shrinks while the inner FEP layer melts, resulting in filling of all empty space inside the tubing with FEP.