A MODEL FOR THE DESCRIPTION, SIMULATION, AND DECONVOLUTION OF SKEWED CHROMATOGRAPHIC PEAKS

A family of models is proposed for the description of skewed chromatog raphic peaks, based on the modification of the standard deviation of a pure Gaussian peak, by the use of a polynomial function, h(t) = He-(1 /2([t-tR]/[s0+s1(t-tR)+s2(t-t)2+...])2), H and t(R) are the height and time at the peak maximum, respectively. The model has demonstrated a high flexibility with peaks of a wide range of asymmetry and can be us ed to accurately predict the profile of asymmetrical peaks, using the values of efficiency and asymmetry factor measured on experimental chr omatograms. This possibility permits the simulation of chromatograms a nd the optimization of the separation of mixtures of compounds produci ng skewed peaks, where both the position and peak shape are considered . A first-degree polynomial was adequate for peaks of moderate asymmet ry, but higher degree polynomials were preferable for peaks showing a high asymmetry, including those with negative skewness. The proposed m odels can be employed in the resolution of overlapped peaks in binary and ternary mixtures of compounds, or to improve the accuracy in the e valuation of peak shape parameters. The results obtained with the prop osed models were comparable or even superior to those achieved with th e exponentially modified Gaussian model.