New approaches to the calculation and interpretation of asymmetry factors of chromatographic peaks

Resumo

The suitability of the determination of the asymmetry factor of chromatographic peaks by the ratio of areas of two components separated by a perpendicular dropped from the maximum of the peak to the base-line, A_s* = S_b/S_a, where symbol a corresponds to the leading edge of the peak and b is for its tailing slope, is discussed. It is demonstrated that this method enables the estimation of the asymmetry of even partially separated chromatographic signals, including those eluted “in the tail” of intense peaks of solvents. The concepts of the asymmetry index I(A_s*) and its increment ΔI(A_s*) = (A_s*)–I(A_s*) are introduced, which ensures the characterization of the asymmetry of peaks of polar analytes with respect to the asymmetry of nonpolar reference components, that is, the separation of the effects of the polarity of analytes and their quantities injected into the chromatographic column on this parameter. For the first time we revealed a correlation of the asymmetry factors of compounds of different chemical nature with such a characteristic of their polarity as the difference in chromatographic separation temperature and the normal boiling point of analytes.