Simple and sensitive protein detection system using UV LEDs and liquid core waveguides - art. no. 675505

Protein concentrations are traditionally analyzed in the ultraviolet at 280nm using laboratory spectrophotometers. Recently, AlGaN/GaN deep ultraviolet Light Emitting Diodes (LED) became available in the 250 nm to 350 nm wavelength region. An inexpensive fiber optic detection system based on these UV LEDs and photodiodes has been developed. Measurement stability, noise and drift will be discussed. To improve sensitivity of the detection system, microliter volume liquid core waveguide sampling cells with 10 cm and 50 cm pathlength were evaluated. With a continuous flow setup, protein concentrations as low as 1 mu g/mL and 0.2 mu g/mL were detectable in a 10 cm and a 50 cm pathlength cell respectively, based on a 10 mAU absorbance signal and a signal to noise ratio greater than 10.