The fiber-optic-based UV-visible absorbance detector for continuous free flow electrophoresis, utilizing focusing elements

The ability to perform UV detection in a one-dimensional array of 48 longitudinal flow cells for components separated by Continuous Free Flow Electrophoresis apparatus was explored. A PC controlled, scanning on-line UV detector was designed to allow for single UV wavelength monitoring across a one-dimensional array of 48 longitudinal flow cells interfaced to a Continuous Free Flow Electrophoresis apparatus. In the detection scheme, the UV light is sequentially passed through each of the 48 flow cells. The main components employed in designing the detector were a stepper motor mechanism to position the light source probe and a detection probe sequentially at each sample flow cell. The detector was incorporated with a deuterium Ultra Violet light source, fiber optic cables to transmit light and a spectrometer. Spectral data was collected from each tube, stored and analyzed. Focusing lenses in the design enhanced the UV light signal. The design integrated on-line acquisition of absorbance spectra of components separated by CFFE. Benzoic acid standard solutions were used to examine the performance of the detector. Chloroquine diphosphate and 4-nitrophenol were used as test solutes to determine the detector's ability to distinguish analytes separated in the CFFE. The development of the on-line UV detector considerably reduced the amount of labor and the time required to analyze components. The analysis time was reduced from hours to a couple of minutes.