| 摘要 |
The invention relates to a method and a device for determining a substance concentration by means of fluorescence spectroscopy. A sample (5) is impinged with at least one first electromagnetic radiation (S1), the intensity of which is modulated with at least two different modulation frequencies (f1, f2). A fluorescent radiation (S1') emitted by the sample (5) is determined by means of a detector (6) and analyzed with respect to the phase position of the fluorescent radiation relative to a respective first reference phase position for each modulation frequency, said reference phase position resulting for a known substance concentration in the sample (5), preferably an absence of the substance in the sample. The detector (6) is also impinged with at least one second electromagnetic radiation, the intensity of which is modulated with at least one third modulation frequency (f3) that is different from the first and the second modulation frequency. The second radiation (S2) does not interact with the sample (5), and the second radiation (S2) that is incident on the detector (6) is analyzed with respect to the phase position of the second radiation relative to a second reference phase position in order to determine the substance concentration in the sample (5) independently of state changes. |
