Equations for Calculation of Chromatographic Figures of Merit for Ideal and Skewed Peaks

Abstract

By use of the exponentially modified Gaussian (EMG) as the skewed peak model, empirical equations based solely on the graphically measurable retention time, tR, peak width at 10% peak height, W0.1, and the empirical asymmetry factor, B/A, have been developed for the accurate and precise calculation of parameters (termed chromatographic figures of merit (CFOMs)) characterizing both Ideal (Gaussian) and skewed chromatographic peaks. These CFOMs Include: the number of theoretical plates (observed efficiency), Nsys; the maximum efficiency attainable if all asymmetry is eliminated, NMAX; the EMG peak parameters, tG, σG, and τ; the first through fourth statistical moments; the peak skew and peak excess, γs and σE; and two new CFOMs—the relative system efficiency, RSE, and the relative plate loss, RPL. Equations for the number of theoretical plates and the second central moment (variance) are accurate to within ±1.5% for 1.00 ≤ B/A ≤ 2.76. Width and B/A measurements at 10% peak height are recommended. © 1983, American Chemical Society. All rights reserved.