Biomolecule analysis by fluorescence intermittence signal recognition

A method for identifying a variant of a biomolecule among a plurality of variants of the biomolecule, said method comprising the steps of

• a. acquiring a fluorescence intermittency signal pattern for each variant of the plurality, wherein each of the variants is labelled with a fluorophore exhibiting spontaneous fluorescence intermittency upon excitation;
• b. determining and associating a fluorescence intermittency signal characteristic for each of said variants;
• c. providing a sample comprising a variant of the plurality, and labelling the variant in the sample with said fluorophore, and acquiring a fluorescence intermittency signal from the labelled variant;
• d. determining a presence of a fluorescence intermittency signal characteristic as determined in step b. in the acquired fluorescence intermittency signals from the sample;
• e. establishing the presence and optionally, the quantity and/or localisation, of a variant of the biomolecule in the sample based on the fluorescence intermittency signal characteristic determined from the fluorescence intermittency signal acquired from the sample and the fluorescence intermittency signal characteristic determined in step b.