Abstract: Chromatographic peaks of varying width are detected and integrated by a method and apparatus that uses only the leading edge of the peak itself to detect the onset of the peak and to select for integration of the peak a filter detector having a time constant which matches the filter characteristics to the signal being monitored.A plurality of filter detectors having different time constants are used for identifying the beginning of a peak. The output of all of the filter detectors is scanned to identify the onset of a peak, and the most appropriate filter detector is selected for integrating the peak.