Effect of Detector Nonlinearity on the Height, Area, Width, and Moments of Peaks in Liquid Chromatography with Absorbance Detectors

The effect of nonlinear absorbance detectors on chromatographic peak height, area, centroid, and second moment is experimentally Investigated. In accord with theory developed previously, those properties related to the even moments, such as the area and peak width, are most strongly Influenced by detector nonlinearity, whereas odd moments of symmetric (Gaussian) peaks are not altered. This Is In contrast to the behavior of the effect of nonlinear Isotherms which shift the position of the peak centroid as well as alter peak symmetry. We have shown that even with relatively narrow spectral slit widths (2 nm) absorbance detectors can be quite nonlinear even at low concentration (1 mM) and at absorbances considerably below the stray radiation limits of the Instrument.