Use of PTFE coils in post-column photochemical reactors for liquid chromatography--application to pharmaceuticals

The advantages and the performance of PTFE reaction coils in photochemical reaction detectors for high-performance liquid chromatography (HPLC) are discussed. The excellent performance of these materials at irradiation wavelengths below 300 nm is based on a diffuse radiation transfer and an internal reflectance (light-tube) effect. Optimal coil designs can be obtained from signal vs. flow-rate curves for a particular application. Lamp performance has to be tested periodically and the reactor should be equipped with an efficient cooling system. Application of the principle to the fluorimetric detection of clobazam and phenothiazines after HPLC separation is discussed. The sensitive detection of these pharmaceuticals and their metabolites in serum with a minimum of sample handling demonstrates the potential of photochemical reaction detectors.