Simultaneous laser-induced fluorescence, coaxial thermal lens spectroscopy and retro-reflected beam interference detection for capillary electrophoresis

A simultaneous laser-induced fluorescence (LIF), coaxial thermal lens spectroscopy (TLS) and retro-reflected beam interference (RBI) detection for capillary electrophoresis (CE), has been described. In its optical scheme, a diode-pump solid-state (DPSS) laser was employed as the pump laser in both LIF detection and coaxial TLS detection, and a He–Ne laser was utilized as the probe laser in coaxial TLS detection and RBI detection. In addition, RBI signals with and without thermal lens had been theoretically compared to ensure the reliability of the RBI signal. Moreover, the focus length of the key lens has been optimized to improve the performance of the proposed detection. The last but not least, several determinations were taken to evaluate its limit of detection, linear range as well as relative standard deviation, all of which indicate no worse results compared with former reports. LIF and coaxial TLS detection owned high sensitivity, and RBI detection indicated versatile property, based on which the reported detection achieved a sensitive and universal detection for CE.