Lab-on-a-chip technology and its application to drug analysis

The aim of this work was: 1- Improvement of the performance of powder-blasted (pb) microchips by applying polyvinyl alcohol (PVA) as a permanent coating. It was found that the limited electrophoretic resolution obtained in powder-blasted (pb) chips could significantly be improved by coating the channels with polyvinyl alcohol. The performance of coated and uncoated powder-blasted (pb) devices as well as coated and uncoated wet chemical etched (wc) chips was compared in electrophoretic separations of fluorescently labeled test compounds. 2- Development and validation of fast methods based on microchip capillary electrophoresis (MCE) to determine some therapeutic and abuse drugs in formulations and human urine. Drugs such as central nervous system stimulants (ephedrine and pseudoephedrine) and diuretics were successfully determined using MCE. A fast micellar electrokinetic capillary chromatography (MEKC) method was introduced for the determination of FITC-labeled ephedrine and pseudoephedrine. The method was successfully applied to the analysis of the respective drugs in pharmaceutical formulations and human urine. Furthermore, a fast MCE method was developed for the determination of diuretics in formulations and human urine. Different light sources were used utilizing either a mercury lamp (330-380 nm), a HeCd laser (325 nm) or a pulsed frequency doubled Nd:YAG-laser (266 nm). The HeCd was chosen as an excitation light source which provided a higher sensitivity for the detection of the diuretics. The developed MCE method was successfully applied to formulations and human urine without interference from other active ingredients. It can be concluded that, MCE-separations of drugs are completed within seconds rather than several minutes as in HPLC. Furthermore as a chip electrophoresis can be integrated into portable analytical devices, this approach appears to be especially attractive for field analysis and point of care diagnostics