A chromatographic optical detection system includes an optical detector disposed to receive light scattered from a stream of particles and configured to convert the received light to an electrical signal; a signal-processing unit in signal communication with the optical detector to receive the electrical signal, and configured to convert the electrical signal to digital pulses and count the digital pulses to output a first signal corresponding to a number of particles detected in a time interval, and configured to integrate and digitize the electrical signal to output a second signal corresponding to the number of particles detected in the time interval; and a data station in signal communication with the signal-processing unit, and configured to select the first signal, if the number of particles detected in the time interval is less than a threshold criterion, and to select the second signal if the number of particles detected in the time interval exceeds the threshold criterion. The threshold criterion is associated with a saturation condition.