The pigtailing approach to optical detection in capillary electrophoresis

A collinear light-emitting diode-induced fluorescence detector for capillary electrophoresis

“…In addition, Wang and Morris [11] have demonstrated a continuous mode-operating UV LED in an analyte velocity modulation device applied for microfluidic devices. In previous reports, the optical scheme of LED-FD is usually based on orthogonal configuration for eliminating the interference of excitation beam [3,4]. Some reports described the use of confocal configuration of LED-FD [11,12], but details were not given.…”

“…The use of light emitting diodes (LED) as excitation source may provide a simple alternative [3][4][5][6]. The combination of extremely high stability, reasonably high intensity, small size, low cost, and very long lifetime makes LED an attractive excitation source for spectroscopic detectors [7,8].…”

“…Several groups have made significant contributions to LED-based fluorescence detection used in CE. Bruno et al [3] presented LEDinduced fluorescence detector (LED-FD) in CE using named pigtailing approach, in which the optical components used for in this detector were assembled into a compact unit using refractive-index matching materials to minimize losses and generation of stray light at the various optical interfaces. Dasgupta and coworkers [4,8] described the use of LED-FD combined with liquid-core waveguide technique in CE, achieving in 200 amole fluorescein of mass detection limit.…”

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

“…Moreover, LED is commercially available at wavelengths ranging from deep-UV to near-IR regions. LED has been used as alternative light source in fluorescence detections [4][5][6]. Unfortunately, owing to its area source and incoherent characteristic, light emitted by an LED usually has a wide divergence angle.…”

Numerical Modelling of Light Propagation for Development of Capillary Electrophoretic and Photochemical Detection Systems

“…Much of this work was limited to two-dimensional projections and two-layer models (no coating present) taking into account capillary material and inner cavity [9]. Previous numerical simulations of light propagation through capillaries have been reported as a tool for flow-cell design and have been limited to prediction of light path for these specific cases only [10]. The numerical problem of ray-tracing through a capillary is an excellent example where advantage can be taken of the ability to perform numerous calculations quickly on a computer to allow for ray paths, ray path overlaps, and resultant light intensities to be calculated.…”