Reversed phase, high-performance liquid chromatography: Effect of the structure of the chemically bonded hydrocarbon ligand on retention and selectivity

Hemetsberger, H.; Behrensmeyer, P.; Henning, J.; Ricken, H.

doi:10.1007/bf02302929

Cited by 79 publications

(15 citation statements)

References 20 publications

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“…Several recent reports have reviewed the state of the art of chemically bonded alkyl reversed-phase packing materials (14)(15)(16)(17). A number of workers have examined the parameters which may affect the chromatographic characteristics of alkyl bonded materials, i.e., carbon content, length of alkyl chain, surface area, and number of unreacted silanol groups (16,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Several studies have shown that the capacity ratio, k', generally increases with increasing carbon content (17,28).…”

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confidence: 99%

Effect of C18 surface coverage on selectivity in reversed-phase liquid chromatography of polycyclic aromatic hydrocarbons

Wise¹,

May²

1983

Anal. Chem.

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1479 (15) Colby, B. N.; Rosecrance, A. E.; Colby, M. E. Anal. Chem. 1981, 53, (16) Glaser, J. A.; Foerst, D. L.; McKee, G. D.; Quave, s. A,; Budde, W. L. (13) Budde, W. L.: Eichelberger, J. W. "Performance Tests for the Evaluament and Laboratories"; Environmental Protection Agency Report EPA-600/4-80-025, April 1980. (14) Sauter, A. D.; Betowskl, L. D.: Smith, T. R.; Strickler, V. A,; Belmer, R. G.; Colby, B. N.; Wllkinson, J. E. HRC CC J . High Resolut. Chromatogr. Chromatogr. Commun, 1981, 4 , 366-384. tion of Computerized Gas ChromatographylMass Spectrometry Equip-1907-1 91 1 I Envrron. Sci. Techno/. 1981, 15, Recent studles trave reported selectlvlty dlfferences for POlycyclic aromatllc hydrocarbons (PAH) on dlff erent octadecylsllane (C18) reversed-phase llquld chromatographlc columns. I n this paper the differences in llquld chromatographic selectlvllty for various Cts columns were correlated with dlfferences In C,, surface coverage data (as determlned from elemental rinalysis and specific surface area measurements on the C,, modlfled slllca). Slgnlflcant dlfferences In selectlvlty were observed for selected PAH and polyphenyl arenes on monornerlc vs,, polymeric C,, materials. Selectlvlty factors for 50 PAH, alkyksubstltuted PAH, polyphenyl arenes, and polycycllc aromatic sulfur heterocycles were determlned on columns from the same manufacturer from seven dlfferent lots of C,, material with dlfferent C,, surface concentratlons.I n addltlon to priovldlng information concerning the contrlbutlon of C18 surface coverage to retentlon rind selectlvlty In the LC separatlon olf these compounds, these studies provide useful Information regarding the selectlon of the approprlate column to optlniize the separatlon of 'selected polycycllc aromatlc compounds.Reversed-phase liquid chromatography (LC) on chemically bonded octadecylsilane (C18) stationary phases is by far the most popular LC mode for the separation of polycyclic aromatic hydrocarbons (PAH). Reversed-phase LC on Cls phases provides excellent selectivity for the separation of PAH isomers and alkyl-substituted PAH isomers ( I ) . Recently, reversed-phase LC on C18 columns has been specified as the method of choice for the analysis of aqueous effluents for the determination of the 16 PAH on the U.S. Environmental Protection Agency's priority pollutant list (2). In addition to the environmental interest in the determination of PAN by LC, PAH are excellent nonpolar solutes for use in the investigation of reversed-phase LC retention mechanisms.Since Schmit et al. (3) i h t described the separation of PAN on a chemically bonded CI8 phase in 1971, numerous reports of LC retention data for PAH on various C18 columns have appeared. Recent studies by Wise et al. (4), Ogan and Katz (5,6), Colmsjo arid MacDonald (7), and Amos (8) found that Cl8 columns from various manufacturertr not only provided different separation efficiencies but often provided different selectivities and iretention characteristics for PAH. In these studies, attention was focused on three groups of...

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confidence: 99%

Effect of C18 surface coverage on selectivity in reversed-phase liquid chromatography of polycyclic aromatic hydrocarbons

Wise¹,

May²

1983

Anal. Chem.

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“…A continuous increase in retention with increasing alkyl chain length has been observed by other investigators (6,8,17,18), although this has usually been reported as a cor relation with log k rather than k. The linear correlation between alkyl chain length and k can be predicted from hydrophobic or partition type interactions because as the chain length is dou bled, the amount of stationary phase is doubled, and it would be expected that the retention volume would also double. The data from our investigation is consistent with these findings, with the exception of the deviation from linearity at higher alkyl chain lengths (C 8 or greater), which was particularly no ticeable for the barbiturate (acidic) solutes and certain of the pyridine (basic) solutes.…”

Section: Effect Of Alkyl Chain Length On Retentionmentioning

confidence: 84%

“…An alternative explanation for the change in slope of the k versus chain length above C 8 may be the altered bonded alkyl chain orien- tation in relation to the silica support surface under certain mobile phase conditions. An increase in the solvent polarity of the mobile phase (e.g., at high percentages of water) has been reported to affect the orientation and fluidity of the longer alkyl chains; the chains are in a more "bristle-like" topography in the presence of a high percentage of organic solvent, and they are in a flatter "blanketlike" orientation at high water concentra tions (17,19). Thus, it is argued that the longer alkyl chains (C 8 , C 12 , and C 18 ) will in teract preferentially with each other forming overlapping chains that lie flat on the sur face, which provide a coating on the surface of the silica of a similar hydrophobic char acter despite the increase in chain length.…”

Section: Effect Of Alkyl Chain Length On Retentionmentioning

confidence: 99%

Characterization of a Range of Alkyl-Bonded Silica HPLC Stationary Phases: Chromatographic Behavior of Neutral, Acidic, and Basic Test Solutes

Barrett

Brown

Shaw

et al. 1996

Journal of Chromatographic Science

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The effect of the chain length (C 1 -C 18 ) of η-alkyl bonded-phase silica packing materials on retention behavior is investigated using three series of substituted test solutes: biphenyls (neutral), barbitu rates (weakly acidic), and pyridines (weakly basic). An excellent correlation between the capacity factor (k) and alkyl chain length is observed in the majority of cases. However, deviations from this re lationship occur when the alkyl chain length is increased beyond C 8 for certain groups of solutes or when there is significant solute in teraction at secondary sites on the packing material. Log k plots showed that the neutral and barbiturate solutes have similar reten tion mechanisms at all the alkyl chain lengths. However, the basic solutes show significant evidence of secondary interactions, which are confirmed by the peak asymmetry data and the lack of correla tion between the log 10 octanol-water partition coefficient (log P) values of the solutes and retention. There is a significant trend to wards improved peak symmetry for the basic solutes when the packing materials having the highest alkyl surface density (C l ,C 2 , and C 3 alkyl chain lengths) are used; this suggests that residual silanols are more effectively masked by the shorter alkyl chain lengths. The neutral biphenyl solutes show a progressive increase in efficiency as the chain length increases, but consistent trends are not observed for the acidic and basic solutes. The results show that the length of the bonded alkyl chain is of primary, though not sole, importance in governing the retention of acidic, basic, and neutral compounds on a series of monofunctional n-alkyl-bonded reversedphase packing materials. Retention mechanisms that might explain the observed separation behavior are discussed. * pKa and log Ρ values were obtained from CRC Handbook (21) and Dissociation Constants of Org ante Bases in Aqueous Solution: Supplement (22).

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“…7a) and their respective idealized drawings (Fig. 7b) follows the "bristle brush", "haystack", "ink bottle", and other models presented by Halasz and Sebestian [21], Hemetsberger et al [22], Lochmuller and Wilder [27] and others [23][24][25]. These experiments reiterate the solution NMR experiments done on alkyl-chain derivatized HPLC silica particles packed within an NMR tube [9,12,[15][16][17][18]26,28,29,31,32], albeit, with the NMR Wool Tube experiments, more solvent mixtures were examined.…”

Section: The Spectral Characteristics Of the Bonded Phase In The Presmentioning

confidence: 97%

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

Cholewa

2004

Journal of Chromatography A

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Reversed phase, high-performance liquid chromatography: Effect of the structure of the chemically bonded hydrocarbon ligand on retention and selectivity

Cited by 79 publications

References 20 publications

Effect of C18 surface coverage on selectivity in reversed-phase liquid chromatography of polycyclic aromatic hydrocarbons

Effect of C18 surface coverage on selectivity in reversed-phase liquid chromatography of polycyclic aromatic hydrocarbons

Characterization of a Range of Alkyl-Bonded Silica HPLC Stationary Phases: Chromatographic Behavior of Neutral, Acidic, and Basic Test Solutes

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

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