Kovats’ retention index

Elution volume, exclusion chromatography Flow rate, column Gas/liquid volume ratio Inner column volume Interstitial (outer) volume Kovats retention indices Matrix volume Net retention volume Obstruction factor Packing uniformity factor Particle diameter Partition coefficient Partition ratio Peak asymmetry factor Peak resolution Plate height Plate number Porosity, column Pressure, column inlet Presure, column outlet Pressure drop... 

Kovats retention indices RI Mass transfer coefficient h... 

Jalali-Heravi, M., Fatemi, M. H. J. Chromatogr. A 915, 2001, 177-183. Artificial neural network modeling of Kovats retention indices for noncyclic and monocyclic terpenes. 

Retention time Kovats retention indices a) R1 SE54 1029, b) RIsP2100 1020... 

Pyrido[l,2-a]pyrimidin-4-one, its 6,7,8,9-tetrahydro derivatives, and their monomethylated derivatives were characterized by gas-chromatographic (GC) retention indices measured on apolar and medium-polar stationary phases (91MI4). Kovats retention indices of alkyl-substituted 4//-pyrido[ 1,2-a]pyrimidines-4-ones and some 6,7,8,9-tetrahydro... 

Peak identification based on both experimental and published Kovats retention indices. Courtesy ofJasbir Chana, Phoenix Natural Products Ltd. 

Fig. 3.7. Schematic representation of the concept of Kovats retention indices.

De Beer et al. [501] reported an extensive comparative study of the chromatographic behaviour of methyl esters and pentafluorobenzyl esters of these substances. They correlated retention data (Kovats retention indices) on nine stationary phases with the structure of the derivatives and with the polarity of the stationary phases with the aim of utilizing these dependences for identification purposes. However, much more significant is the better separation obtained with pentafluorobenzyl esters and the possibility of increasing the sensitivity of the analysis. 

Cabernet wine comparison. One of the objectives of the study was to identify the odoi active compounds of wines with "Brett" flavor through sensory analysis and gas chromatography-olfactometry (GCO). Wines identified by their respective winemakers as having "Brett" character were evaluated by a trained expert sensory panel also, using the technique CharmAnalysis (92-94) for GCO analysis, along with gas chromatography-mass spectrometry (GC-MS), odor-active compounds were identified by their respective Kovats retention indices (95). Contained below is a... 

The simple rule for the prediction of the possibility of GC analysis of organic compounds is based on the reference data of their boiling points. If any compound can be distilled without decomposition at the pressures from atmospheric to 0.01-0.1 torr, it can be subjected to GC analysis, at least on standard nonpolar polydi-methylsiloxane stationary phases. In accordance with this rule, most of the monofunctional —OH compounds (alcohols, phenols) and their S analogs (thiols, thiophenols, etc.) may be analyzed directly. The confirmation of chromatographic properties of any analytes must be not only verbal (at the binary level yes/no ) but also based on their GC Kovats retention indices as the most objective criteria for example ... 

The easiest and most frequently used way to identify essential oil components when using GC/FID is comparison with Kovats retention indices (RI). The use of this type of retention data, derived from two GC columns of different polarities, allows highly reliable identification of large numbers of components in a particular sample. 

Most of the alphatic fractions were separated into normal and branched alkane fractions after the removal of unsaturated hydrocarbon. Most of these subfractions were analysed by GO to give fingerprint chromatograms. These analyses were used to provide data that allowed carbon preference indices, pristane/phytane ratios etc. to be measured. Also, the relative amounts of (17 H, 21/ H 17/3 H, 21 oCH and 17 H, 21(3 H) hopanes, steranes, 4-methyl steranes, carotenoid and other related compounds were assessed from gas chromatograms and reconstructed ion chromatograms. A large number of Kovats Retention Indices (0V-101) were measured and tabulated for these compounds also (10). 

Fatemi, M.H. (2002) Simultaneous modeling of the Kovats retention indices on OV-1 and SE-54... 

Stein, S.E., Babushok, V.I., Brown, R.L.andLinstrom, P.J. (2007) Estimation of Kovats retention indices using group contributions./. Chem. Inf. Model., 47, 975-980. 

Figure 20-4. Diagram to Illustrate how to Determine Kovats Retention Indices. (Courtesy - L.S. Ettre, Anal. Chem., 36, 31 A, 1964)...

Chassevent F., Lebbe J. and Chovin P. (1966) Identification of some volatile constituents of roasted coffee by Kovats retention indices method. 2nd Int. Colloq. Chem Coffee (Paris, 3-7.5.1965), Inst. Fr. Cafe Cacao (IFCC), 161-7. 

The questions in this section are concerned in effect with the use of Kovats retention indices in GC. The Kovats retention index for a compound can be calculated from one of the following ... 

The data in Table 10.5 were obtained by using a GC column operated at constant temperature. Calculate the Kovats retention indices for sample... 

Table I. Kovats Retention Indices for Symmetric Dimer Silanes Dimers...

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