Adverse effects of lag filters used for detector baseline noise suppression in HPLC.

Most detectors used for High Performance Liquid Chromatography employ a lag filter for suppression of baseline noise. This filter is characterised by its time constant, . At high values of (in excess of 0.5 sec), the lag filter seriously distorts the shape of a chromatographic peak, causing reduced peak heights, altered retention times and increased peak width. These changes result in significantly decreased resolution and decreased plate counts. These effects are investigated quantitatively.