A simple and highly sensitive masking fluorescence detection system for capillary array electrophoresis and its application to food and medicine analysis

•A masking fluorescence sharing detection system for capillary array electrophoresis was established.•A special mask combined with convex lenses was designed to modulate signals, without using any extra device to position each channel.•The detection cell was designed to not only decrease noise but also collect fluorescence in multiple directions.•To meet the needs of different excitation wavelengths, the system was adopted modular design which was conducted to facilitate installation and replacement.•The system can be easily home-built, accompanied by high sensitivity as well as high throughput and precision. A high sampling rate, good stability, high throughput 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 optical signal and to collect fluorescences in multiple directions, which greatly raised the sensitivity. Other important parameters including sampling rate, rotating speed and driven voltage laser diode (LDs) have also been investigated. Under optimal conditions, 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 2.0 × 10−2 µg/mL.