Condense-Phase BBCEAS Measurements at UV Wavelength

Broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to make measurements on liquid phase species using a UV LED and an optical cavity formed by R ≥ 0.99 ultra violet mirror set. The detector is an Andor CCD spectrograph. Measurements is made on a number of dyes dissolved in water and placed in a 1 cm quartz cuvette at zero degrees angle of incidence between the cavity mirrors. The most sensitive measurements are made with the R ≥ 0.99 mirror set on congo red at 397 nm which produced an αmin(t) value of 2.1 × 10-6 cm-1 Hz-1/2 and a LOD of 0.19 nM.