Study On A Masking Fluorescence Detection System For Capillary Array Electrophoresis And Its Application

Fast,cost-effective,energy efficient,high-throughput analytical instrument has been a long-pursuing goal.Capillary electrophoresis(CE),as a highly accurate analysis tool,has been a rapid development due to possess the advantages of high resolution,short analysis time,the simplicity of operation and so on.With continuous research,array capillary electrophoresis(CAE)have been urgently needed to development.Because CAE has ability of high-throughput determining of a structure and characteristics.However,there are still few problems unresolved in various CAE,such as positing each channel difficultly,interference signal between channel,low sampling rate and so on.In view of this,a masking fluorescence detection system was fabricated for CAE,with accurate positioning of each channel as well as high sampling rate,stability,sensitivity and throughput.A special mask was rotated by a high-speed DC motor to scan all capillaries for channel signal modulation.At the same time,the performance of new detector was applied to analyze actual samples.This paper includes the following four parts:1.Introduction: In this section,a brief introduction to principles and its development of CAE were given.At present,according to the difference of detector,CAE was mainly classified several apparatus types including UVvisible absorption CAE,time-resolved fluorescence CAE,laser induced fluorescence CAE and so on.Advantages and disadvantages of different CAE were summarized.Based on status quo of CAE,according actual situation of analyzing sample,the significance and aims of this study were put forward.2.A compact,low-cost,highly sensitive masking fluorescence detection system with easy positioning of each channel for capillary array electrophoresis was prepared and studied.A special mask combined with convex lenses was designed to modulate signals,without using any extra device to position each channel.The signal of each channel was detected by a photomultiplier tube,classified and saved by software.The design was used to evidently reduce the rotational vibration of optical components and to stabilize the system.So,a high sampling rate was obtained by increasing the DC motor speed.To improve the optical system,optical fibers instead of conventional bulky optical components were used to transmit the optical signal and to collect fluorescence in multiple directions,which greatly raised the sensitivity.The performance of the detection system was evaluated.This novel system had a well-designed structure,and allowed independent multiple capillary operations and easy microanalysis.Its limit of detection for rhodamine 6G was 20.00 ng/mL.3.Anthraquinone and flavonoids were determined by solid-phase extraction coupled with CAE.An analytical method based on CAE that had been established was adopted to accurate quantitative determination of rutin,emodin,quercetin and 1,8-dihydroxyanthraquinone.An environmentallyfriendly chitin was chosen as adsorbent to enrich analytes.Under optimized condition,the analytical method was proved to be rapid,accurate and simple;and was maked the quantitative determination of the analyte in honey.The experiments show that limit of detection(LOD)ranged from 3.00?200.0 ng/mL and recoveries were in the range of 90.0?107.0% with RSD values 1.8?8.3%.4.Doxorubicin and curcumin was determined by a high-sensitivity dual-wavelength light source-CAE method.Based on CAE established,a double wavelength excitation source laser-induced fluorescence(LIF)detector which compose of a 445 and a 488 nm commercial laser diode was constructed with simple optical path adjustment.Rhodamine 6G was selected as an internal standard because can emit fluorescence at 445 and 488 nm.With curcumin and doxorubicin as target analytes,mixed micelles formed Triton X-100 and sodium dodecyl sulfate(SDS)were used to sensitize the native fluorescence of Analytes and enhance resolution.The optimal electrophoretic separation conditions were made of 10 mM borate buffer containing 20 mM Triton X-100,5 mM SDS,30%(v/v)methanol at pH 9.00 after investigation.The developed method performs LOD of 4.00 ng/mL and 10.00 ng/mL for doxorubicin and curcumin in human urine samples,respectively and recoveries ranging from 94.9?109.3%.