Apparatus and methods for detecting analytes in a sample are provided. The apparatus can include: one or more channels having a detection zone; one or more irradiation sources disposed for irradiating the detection zone with radiation; a detector capable of collecting at least one charge corresponding to an emission beam emitted from the detection zone, the detector having an output; and a time delay integration system coupled to the detector for effecting time delay integration of the at least one charge by accumulating the at least one charge before reading the at least one charge at the output of the detector. Various embodiments provide an apparatus with a multi-notch filter. Various embodiments provide a solid state laser, a micro-wire laser, or an organic light-emitting diode as a irradiation source.