| 摘要 |
A method and apparatus for quantifying an analyte in a gas phase sample comprises: a laser 5 defining a laser axis; an optical cavity having a gas inlet and a gas outlet; a fluorescence detector 11 perpendicular to the axis and arranged to provide a first signal in response to fluorescence in the cavity; an photon detector 9 provided axially external to the cavity, configured as cavity ring-down spectrometer (CRDS), and arranged to provide a second signal; wherein the apparatus is configured to comprise a cavity-enhanced laser-induced fluorescence (CELIF) spectrophotometer; means for supplying a pure gas sample or an analyte-containing gas sample to the cavity through the inlet; and a processor 12 adapted to receive a first signal to calibrate the apparatus and to receive a second signal to provide a measurement of the concentration of the analyte in the sample. |
