Evaluation of the Potential of a Charge-Injection Device for DNA Sequencing by Multiplexed Capillary Electrophoresis

Despite the rapid growth in the use of imaging detectors in spectroscopy, the charge-injection device (CID) has unique features that have not been fully exploited. The advantages of the CID as a two-dimensional array detector for laser-induced fluorescence detection in highly multiplexed capillary electrophoresis are evaluated. In such a system, the CID maintains both high sensitivity and high sampling rate, which are usually difficult to achieve simultaneously with other array detectors. Applying the electronic windowing function significantly improves the scan rate and greatly reduces the volume of data generated. With 1-s exposure time and 488-nm excitation, the detection limit of the system is 10⁻¹² M fluorescein with the device cryogenically cooled and 10⁻¹¹ M fluorescein at ambient temperature. The low dark current of the CID imager allows operation at room temperature without significantly affecting sensitivity when combined with moderate laser powers. We demonstrate that the CID is well suited for high-speed, high-throughput DNA sequencing based on multiplexed capillary electrophoresis with on-column laser-induced fluorescence detection.