How do I use a linear variable filter (LVF) for fluorescence?
You have three primary linear variable filter options for fluorescence measurements:
- Pre-sample. Use the FHS-LVF in-line filter holder and a low-pass LVF-LL filter to block excitation energy from a fiber optic light source above a certain wavelength, so that the light does not interfere with the fluorescence of the sample. The device is situated between the lamp and the sample. If the sample is in a cuvette, you can achieve the same result by using the LVF-CUV-ADP cuvette holder adapter to secure the filter in the holder and then positioning the illumination fiber so that it projects through the filter to the sample.
- Post-sample. By placing the FHS-LVF and a high-pass LVF-HH between the sample and the spectrometer or detector, you can block excitation energy in the fluorescence region by passing light above a certain wavelength. You can achieve the same result with the LVF-CUV-ADP holding the LVF on the “read” port of the cuvette holder.
- Pre- and post-sample. You can combine pre- and post-filtering to further remove unwanted excitation signal from the fluorescence signal.