Miniaturized fiber-in-tube solid-phase extraction as the sample preconcentration method for microcolumn liquid-phase separations

Miniaturized fiber-in-tube solid-phase extraction (fiber-in-tube SPE) has been developed as a solvent-less sample preconcentration technique for microcolumn liquid-phase separation methods. Short capillaries packed with polymer filaments were employed as the extraction tube and the preconcentration power for phthalates in aqueous solutions was studied. On the basis of the successful on-line coupling of this preconcentration method with liquid chromatography (LC), a more miniaturized extraction cartridge, which is installed in the rotor of the micro-injector, has been developed. With a modified commercially available valve, on-line coupling of this sample preconcentration method to capillary electrochromatography (CEC) was also investigated.