CASTDan:Abstract9

Kostov Y., Rao. G. (1999) Simple low-cost device for fluorescence ratiometric measurements. ''Rev. Sci. Instr.'', 70, 4466-4470.

Abstract

An all-solid-state, low-cost device for fluorescent wavelength-ratiometric detection is described. Ultrabright light-emitting diodes were used as light sources. This allowed electronic modulation of the light, simple optical configuration, and miniaturization of the instrument. Narrow-bandpass interference filters were used for wavelength separation. Detection was accomplished by high-sensitivity, large-surface PIN photodiodes. An integrating double-ramp technique with fixed upper and lower thresholds was employed for conversion of the light intensities into time intervals. The duty ratio of the output signal was a function of the fluorescence intensity ratio. Additionally, the concentration of the fluorophore could be measured. The device could be easily designed as a battery-operated version. It could be used for a variety of ratiometric fluorescence measurements. © 1999 American Institute of Physics. [S0034-6748~99!01412-4]

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