A glycerol assisted light-emitting diode-induced fluorescence detector for capillary flow systems

Signal-to-noise ratio enhancement of the compact light-emitting diode-induced fluorescence detector

“…The calibration of the pinhole, capillary flow cell, and collection fiber was always very important to the SNR. In addition, the use of RIMF might be good for SNR enhancement [16]. Based on these analyses, the four key parameters were further investigated and found to still have room for improvement.…”

“…It had been demonstrated that, for the optical fibers system, the attendance of RIMF could enhance the SNR to about two times [16]. The optical lenses system was unsuitable for the application of RIMF which eliminated the focusing effect of lenses and resulted in a fall of sensitivity.…”

A compact and highly sensitive light-emitting diode-induced fluorescence detector for capillary flow systems

“…So the excitation light intensity in a light-emitting diode-induced fluorescence detector (LED-FD) is usually under 0.1 W/m 2 . It is at least ten times lower than that in a laser-induced fluorescence detector (L-FD) [7]. Generally, LEDs and lasers are different in nature.…”

“…Either the use of HB LEDs or pulse modulation mode driving to higher light intensity could enhance the SNR over several times [12,14]. And the use of refractive index matching fluid (RIMF) could increase the SNR over two times [7]. The data in Table 1 suggested that the LOD of our LED-FD could be further improved by applying brighter LED, pulse driving mode, and RIMF [12].…”

“…The Full Wave at Half Maximum (FWHM) at visible light is ∼30 nm for LEDs, while for lasers it is ∼0.1 nm. Therefore, the background noise in an LED-FD is generally several times higher than that in an L-FD [7]. All of these factors lead LED-FDs to a much poorer detection limit.…”