Chromatography retention indices

Arey, J.S., Nelson, R.K., Xu, L., Reddy, C.M. (2005) Using comprehensive two-dimensional gas chromatography retention indices to estimate environmental partitioning properties for a compete set of diesel fuel hydrocarbons. Anal. Chem. 77 7172-7182. 

The analytical data in the OCAD is derived from four different techniques. These are nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), gas chromatography/mass spectrometry (GC/MS), and gas chromatography retention indices (GC(RI)). With a few exceptions, the OCAD contains only data of compounds that are listed in the schedules of the CWC and their derivatives of BSTFA and dimercaptotoluene. 

The types of analytical data contributed are Mass Spectra (MS), Infrared (IR) spectra, Nuclear Magnetic Resonance (NMR) spectra and Gas Chromatography Retention Indices (GC(RI)). The analytical data are contributed either in hard copy or as electronic files in acceptable formats. MS data is contributed in the electronic format. 

The electronic MS on-site databases are prepared from the certified electronic version of the OCAD (e-OCAD). This version is compiled using the NIST programs (NIST MS Search/Analysis and AMDIS) and is in the form of a NIST MS Database. The e-OCAD does not contain Gas Chromatography retention indices (GC(RI)) that are required for on-site use. To create an electronic MS onsite database, the certified version of e-OCAD, which at the moment contains only MS data, is merged with the certified (GC(RI)), which is in an excel spreadsheet. After merging these data, an AMDIS version of the database is created, which is compatible with the AMDIS software used by the on-site GC/MS equipment (for more details on the software, refer to Chapter 2 and Chapter 4) (5). The MS on-site database can be sent for an inspection as a whole database or as an extract of the whole database. AMDIS is software that is used by the GC/MS on-site equipment... 

Xu, Q.-S., Massart, D.L., Liang, Y.-Z. and Eang, K.-T. (2003) Two-step multivariate adaptive regression splines for modeling a quantitative relationship between gas chromatography retention indices and molecular descriptors. /. Chromat., 998, 155-167. 

GC—gas chromatography retention indices MS—mass spectral interpretation MSA—mass spectra match with API reference spectra. 

There are many books and other sources that discuss the retention index from theoretical and practical aspects. One comprehensive book is "The Sadtler Standard Gas Chromatography Retention Index Library" [15]. This series of book (from Volume 1 to Volvune 4) provides detailed data on the retention indices for more than 2,000 compoimds under varying isothermal and temperature programming GC conditions for the purpose of the general identification of unknown compoimds. 

The Sadtler Standards Gas Chromatography Retention Index Library, Sadtler and Sanyo, 1985. 

Sadder Standard Gas Chromatography Retention Index Library. Vnls. 1-4, Philadelphia Biu-Rad Laboratories, Sadtler Division, 1984-8S, For reviews of two-dimensional GC. see M. Adahehour. J. Beens. R, J. J. Vreuls, U. A. Th. Brinkman. Trends Anal. Chem. (TRAC). 2006.25, 438 2006,25. 540 2066,25, 726,... 

Kovats, E. and A. Wehrli (1959), Gas-chromatography characterization of organic compounds. III. Calculation of the retention indexes of aliphatic, alicyclic and aromatic compounds . Helv. Chim. Acta, Vol. 42, p. 2709. 

Van Den Dool, H. and P.D. Kratz (1963), Generalization of the retention index system including linear temperature programmed gas-liquid partition chromatography . J. Chromatogr, Vol. 11, p. 463. 

Kovat s retention index (p. 575) liquid-solid adsorption chromatography (p. 590) longitudinal diffusion (p. 560) loop injector (p. 584) mass spectrum (p. 571) mass transfer (p. 561) micellar electrokinetic capillary chromatography (p. 606) micelle (p. 606) mobile phase (p. 546) normal-phase chromatography (p. 580) on-column injection (p. 568) open tubular column (p. 564) packed column (p. 564) peak capacity (p. 554)... 

Fig. 3. (a) Flame ionization detector (fid) response to an extract of commercially processed Valencia orange juice, (b) Gas chromatography—olfactometry (geo) chromatogram of the same extract. The abscissa in both chromatograms is a normal paraffin retention index scale ranging between hexane and octadecane (Kovats index). Dilution value in the geo is the -fold that the extract had to be diluted until odor was no longer detectable at each index. 

Qualitative (identification) applications depend upon the comparison of the retention characteristics of the unknown with those of reference materials. In the case of gas chromatography, this characteristic is known as the retention index and, although collections of data on popular stationary phases exist, it is unlikely that any compound has a unique retention index and unequivocal identification can be effected. In liquid chromatography, the situation is more complex because there is a much larger number of combinations of stationary and mobile phases in use, and large collections of retention characteristics on any single system do not exist. In addition, HPLC is a less efficient separation... 

Retention index The parameter used in gas chromatography to measure the retention of an analyte. 

Smith, R. M. and Finn, N., Comparison of retention index scales based on alkyl aryl ketones, alkan-2-ones and 1-nitroalkanes for polar drugs on re-versed-phase high-performance liquid chromatography,. Chromatogr., 537, 51,1991. 

GC-EAD Gas chromatography combined with an EAG detector GC-MS Gas chromatography combined with mass spectrometry HPLC High performance liquid chromatography KI Kovats retention index... 

Schuberth J. 1994. Joint use of retention index and mass spectrum in postmortem test for volatile organics by headspace capillary gas chromatography with ion-trap detection. J Chromatogr A 674 63-71. 

Kovat s retention indexes analychem Procedure to identify compounds in gas chromatography the behavior of a compound Is Indicated by Its position on a scale of normal alkane values (for example, methane = 100, ethane = 200). ko-vats ri ten-... 

PG Muijselaar, HA Claessens, CA Cramers. Characterization of pseudostation-ary phases in micellar electrokinetic chromatography by applying linear solvation-energy relationships and retention indexes. Anal. Chem. 69 1184—1191... 

PGHM Muijselaar, HA Claessens, CA Cramers. Application of the retention index concept in micellar electrokinetic capillary chromatography. Anal Chem 66 635-644, 1994. 

G.l.c. papers of interest include the classification of 22 acyclic monoterpenoid alcohols according to retention indexes, resolution of cyclic ketones [e.g. ( )-menthone, ( )-isomenthone] as diethyl (+)-tartrate acetals, and the use of lanthanide shift reagents to resolve non-terpenoid racemic epoxides.The occurrence and prevention of monoterpenoid hydrocarbon isomerization during silica gel chromatography has been examined and the separation of monoterpenoids and sesquiterpenoids by gel permeation chromatography is reported. Monoterpenoid hydrocarbons have been selectively extracted from essential oils using dimethylsilicone. ... 

The aids to chromatography include a) resolution calculations on chromatograms of standard mixtures to monitor column performance, b) calculation of Kovats retention index for help in identifying peaks, and (c) multiple point calibration curves for improved quantitation. The file searching routines access two sets of data. Information (such as molecular formula, molecular weight) is stored on 3100 compounds from the Arctander data( ). This allows a quick computer search through the data which is difficult... 

W. Jennings and T. ShSoaxnoto, Qualitative Analysis of Flavor andFragrance Volatiles by Glass Capillary Gas Chromatography, Academic Press, Inc., New York, 1980 also includes retention indexes and mass spectral data. 

The extract of the volatiles is separated by high resolution gas chromatography (HRGC) and the odor of the compounds is assessed by sniffing the effluent of the GC column in parallel with the FID-detection. This technique allows the detection of odor-active volatiles, the determination of their odor qualities and, most important, the combination of these sensory data with an analytical parameter, the retention index (RI). In Figure 2, the results of... 

The McReynolds constants listed are differences in retention index units between die reference compound run on squalane and on die other phases listed. The last entry in the table shows die absolute retention indices for the reference compounds on squalane. Reference compounds are (1) benzene, (2) 1-butanol, (3) 2-pentanone, (4) 1 nitropropane, and (5) pyridine. (Note that Rohrschneider s constants are based on these reference compounds and may differ slightly from the McReynolds constants. The reference compounds for Rohrschneider s constants are (1) benzene, (2) ethanol, (3) 2-butanone, (4) nitromethane, and (5) pyridine.) The minimum temperature is that at which normal gas-liquid chromatography (GLC) behavior is expected. Below that temperature, die phase will be a solid or an extremely viscous gum. The maximum temperature is that above which die bleed rate will be excessive. 

Fischer R.C., R. Wittlinger, and K. Ballschmiter. 1992. Retention-index based vapor pressure estimation for polychlorobiphenyl (PCB) by gas chromatography. Fres. J. Analyt. Chem. 342 421-425. 

Identification of these components was based on GC/MS and retention index information. Novel compounds were isolated by preparative capillary gas chromatography and spectroscopically identified by interpretation of infrared, nuclear magnetic resonance and mass spectra. In... 

Retention index library mass chromatography interpretation and search for specific chemical shifts and couplings... 

J.R. Hancock and G.R. Peters, Retention index monitoring of compounds of chemical defence interest using thermal desorption gas chromatography, J. Chromatogr., 538, 249-257 (1991). 

J. Takacs, M. Rockenbauer and I. Olacsi, Determination of the relationship between retention index and column temperature in gas chromatography through the temperature-dependence of the net retention volume, 7. Chromatogr., 42, 19-28 (1969). 

M.V. Budahegyi, E.R. Lombosi, T.S. Lombosi, G. Tarjan, I. Timar and J.M. Takacs, Twenty-fifth anniversary of the retention index system in gas-liquid chromatography, J. Chromatogr., 271, 213-307 (1983). 

M.T. Soderstrom, R.A. Ketola and O. Kostiainen, Identification of nerve agents and their homo-logues and dialkyl methylphosphonates by gas chromatography/Fourier transform infrared spectrometry (GC-FT1R), Part II Spectral search with help of retention indexes, Fresenius J. Anal. Chem., 352, 550-556 (1995). 

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