Patent ID: 7799575

Claim:
A method of calibrating a flow cytometer, the method comprising: providing a flow cell through which a sample to be studied flows and a fluorescence detection assembly comprising a spectral sorting arrangement for separating fluorescence extending over a wavelength range into a plurality of at least four wavelength bands, and a single detector module with a plurality of channels to which the spectral sorting arrangement is optically coupled so that respective channels thereof receive respective ones of the wavelength bands; flowing a fluorescent calibration sample through the flow cell which fluoresces across the wavelength range; measuring the intensity of the fluorescent calibration sample in each of the channels of the detector; and determining normalization factors for each channel from a known spectral response function for the fluorescent calibration sample and the measured intensities of the fluorescent calibration sample, the normalization factors being suitable for adjusting subsequent measured fluorescence intensities of samples to be investigated, the method further comprising flowing a further fluorescent calibration sample through the flow cell which fluoresces across the wavelength range; and measuring the intensity of the further fluorescent calibration sample in each of the detector channels; wherein the normalization factors are determined also from the measured intensities of the further fluorescent calibration sample by solving first and second simultaneous equations corresponding respectively to the fluorescent calibration sample and the further fluorescent calibration sample.