Twenty-fifth anniversary of the retention index system in gas—liquid chromatography

Linear retention indices in gas chromatographic analysis: a review

“…As is wellknown, this homologous series elutes, when isothermal GC conditions are applied, with retention times increasing exponentially. Under such conditions a semilogarithmic relationship exists between the adjusted retention times ( ) of the n-paraffins and their carbon numbers (c n ); a and b are constants [see equation (6)]: (6) This system was based on the fact that each analyte is referenced in terms of its position between the two nparaffins that bracket its retention time. Furthermore, the index calculation is based on a linear interpolation of the carbon chain length of the two bracketing paraffins.…”

“…The McReynolds values are used to evaluate the degree of similarity between stationary phases, to rank the phases by degree of polarity and to predict the elution order of the analytes. The Rohrschneider concept and related calculation methods represent a very important research area, 6,7,13 and both the aforementioned approaches are widely applied to characterize and classify stationary phases. However, the McReynolds system may often contain erroneously measured data; an additional drawback is that the constants are determined only at 120°C.…”

“…However, when isothermal steps are included in the temperature programme or the rate is changed during the analysis, the calculation of the indices is more troublesome. [5][6][7] It is worthy of note that discrepancies may arise from the fact that the retention index values are reported by many different laboratories and the operating conditions are not always reliable. Moreover, it should be pointed out that differences may also arise from the use of columns coated with identical stationary phase but manufactured by distinct companies.…”

“…The prediction of programmed temperature retention indices is also an in-depth discussed subject, 12 involving the calculation and theoretical determination of the elution order of many compounds. Retention index systems have been exhaustively reviewed by Budahegyi et al 6 and Tarján et al 7 The present contribution provides an overview of the theoretical aspects and applications of retention indices to gas chromatographic analysis. It is certain that the references cited in this review represent a very small part of the studies performed on retention index theories and their applications.…”

Task 2 Report: Algorithm Development and Performance Analysis

“…While a variety of different retention indices can be defined, the most commonly used retention index method is the Kovat's Retention Index system (for review, see Budahegyi et al, 1983). In this method the retention index of a compound describes its chromatographic elution relative to a series of normal alkanes (saturated hydrocarbons).…”