Application of Gas Chromatographic Retention Indices to GC and GC–MS Identification with Variable Limits for Deviations Between Their Experimental and Reference Values

The potential of the new algorithm for comparing experimental and reference values of gas chromatographic retention indices (RI) is discussed. This algorithm is designed to eliminate significant elements of uncertainty typical of numerous contemporary recommendations, primarily the fixed limiting values of permissible deviations, DRI = (RIref – RIexp). The algorithm proposed implies the calculation of deviations DRI for selected most reliably identified constituents of multicomponent mixtures with known reference RI values, followed by calculation of coefficients of regression equations DRI = (RIref – RIexp) = aRIexp + b for total sets of analytes. These equations allow recalculating the experimentally determined RIs into the corrected values RIcorr = RIexp + DRI. Such algorithm makes it possible to use reference RI values for semi-standard nonpolar polydimethylsiloxane phases (with 5% phenyl groups and others) for the comparison with data determined with standard nonpolar polydimethylsiloxanes and vice versa. It is applicable both to statistically processed reference data and to results of single measurements.