Effect of alkyl chain length of the stationary phase on retention and selectivity in reversed-phase liquid chromatography

Tanaka, Nobuo; Sakagami, Keiko; Araki, Mikio

doi:10.1016/s0021-9673(01)91384-6

Cited by 114 publications

(47 citation statements)

References 31 publications

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“…Correlations between methylene selectivity and ligand chain length [13][14][15], bonded phase carbon loading [ 16,17] and surface coverage [ 18,19] have been confirmed. In addition to the stationary phase, the type of the organic modifier and mobile phase composition will also influence methylene selectivity [20,21 ].…”

Section: Column Selectivitymentioning

confidence: 72%

Possibilities and pitfalls in defining selectivity in HPLC

Szepesy

2000

Chromatographia

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Definition of selectivity Classification of solvent selectivity Rohrschneider-McReynolds system Solvent selectivity triangle Solubility parameter Linear solvation energy relationships Prediction of selectivity SummaryDefinition of chromatographic selectivity and the different selectivity terms, for example column selectivity, mobile phase selectivity, and temperature selectivity are discussed briefly. For classification of solvent selectivity the Rohrschneider-McReynolds system, the solvent selectivity triangle (SST) concept, the solubility parameter approach, and the linear solvation energy relationships (LSER) are compared. Shortcomings of the SST concept and application of the LSER method for the prediction of selectivity are discussed.

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Section: Column Selectivitymentioning

confidence: 72%

Possibilities and pitfalls in defining selectivity in HPLC

Szepesy

2000

Chromatographia

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“…Additionally, grafting of organic molecules onto a silica surface was confirmed by DRIFT measurement (Supporting Information, Figure S4). The solid-state 13 conformations and mobility of the long alkyl chains, respectively, of the Sil-MEPG-C 18 -1 and Sil-MEPG-C 18 -2 phases. 13 C CP/MAS NMR spectroscopy revealed highly ordered (trans conformation) alkyl chains in the Sil-MEPG-C 18 -1 phase (Figure 1a) compared to the Sil-MEPG-C 18 -2 phase (Figure 1b) Figure S5a,b), indicating that the mobility of the alkyl chains is low even at higher temperature and the results agree with the results of 13 C CP/ MAS NMR spectroscopy.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Design of C₁₈ Organic Phases with Multiple Embedded Polar Groups for Ultraversatile Applications with Ultrahigh Selectivity

Mallik¹,

Qiu

Oishi³

et al. 2015

Anal. Chem.

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For the first time, we synthesized multiple embedded polar groups (EPGs) containing linear C18 organic phases. The new materials were characterized by elemental analysis, IR spectroscopy, (1)H NMR, diffuse reflectance infrared Fourier transform (DRIFT), solid-state (13)C cross-polarization magic angle spinning (CP/MAS) NMR, suspended-state (1)H NMR, and differential scanning calorimetry (DSC). (29)Si CP/MAS NMR was carried out to investigate the degree of cross-linking of the silane and silane functionality of the modified silica. Solid-state (13)C CP/MAS NMR and suspended-state (1)H NMR spectroscopy indicated a higher alkyl chain order for the phase containing four EPGs than for the phase with three EPGs. To correlate the NMR results with temperature-dependent chromatographic studies, standard reference materials (SRM 869b and SRM 1647e), a column selectivity test mixture for liquid chromatography was employed. A single EPG containing the C18 phase was also prepared in a similar manner to be used as a reference column especially for the separation of basic and polar compounds in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), respectively. Detailed chromatographic characterization of the new phases was performed in terms of their surface coverage, hydrophobic selectivity, shape selectivity, hydrogen bonding capacity, and ion-exchange capacity at pH 2.7 and 7.6 for RPLC as well as their hydrophilicity, the selectivity for hydrophilic-hydrophobic substituents, the selectivity for the region and configurational differences in hydrophilic substituents, the evaluation of electrostatic interactions, and the evaluation of the acidic-basic nature for HILIC-mode separation. Furthermore, peak shapes for the basic analytes propranolol and amitriptyline were studied as a function of the number of EPGs on the C18 phases in the RPLC. The chromatographic performance of multiple EPGs containing C18 HILIC phases is illustrated by the separation of sulfa drugs, β-blockers, xanthines, nucleic acid bases, nucleosides, and water-soluble vitamins. Both of the phases showed the best performance for the separation of shape-constrained isomers, nonpolar, polar, and basic compounds in RPLC- and HILIC-mode separation of sulfa drugs, and other polar and basic analytes compared to the conventional alkyl phases with and without embedded polar groups and HILIC phases. Surprisingly, one phase would be able to serve the performance of three different types of phases with very high selectivity, and we named this phase the "smart phase". Versatile applications with a single column will reduce the column purchasing cost for the analyst as well as achieve high separation, which is challenging with the commercially available columns.

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“…2 A -C. Alkylbenzenes with different carbon numbers (group A) gives information about the hydrophobic interaction. 5,6 Furthermore, pairs of PAHs each having n′ and n′+1 aromatic rings (group B) are expected to indicate the strength of the π-π interaction through separation factors (α n′+1 ), and pairs of planar and non-planar PAHs each having the same number of aromatic rings (group C) are expected to provide detailed knowledge about the planar recognition ability of the columns. 7,8 On the other hand, silica gels modified with In-and Sn-porphyrins (In-and Sn-CPTPP S ), where In-and Snporphyrins are bound perpendicularly to the surface of silica gels similarly to the cases of PYE 3,4 and Cu-PP D columns 2 , were reported 9,10 after our previous communication.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of the interaction due to an alkyl group(s), it is well known that the longer alkyl chain gives the larger retentivity. 5,6 If Cu-PCS D has an interaction concerned with alkyl group in addition to the π-π interaction, the capacity factors of alkylbenzenes become longer as the number of alkyl chains increases. Thus, we examined the relationship between the capacity factor and the number of alkyl chains (n).…”

Section: Separation Characteristics Of Cu-pcs D Columnmentioning

confidence: 99%

Separation Characteristics of Aminopropyl Silica Gels Modified with Copper-Phthalocyanine as High Performance Liquid Chromatography Stationary Phase

et al. 1998

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Effect of alkyl chain length of the stationary phase on retention and selectivity in reversed-phase liquid chromatography

Cited by 114 publications

References 31 publications

Possibilities and pitfalls in defining selectivity in HPLC

Possibilities and pitfalls in defining selectivity in HPLC

Design of C₁₈ Organic Phases with Multiple Embedded Polar Groups for Ultraversatile Applications with Ultrahigh Selectivity

Separation Characteristics of Aminopropyl Silica Gels Modified with Copper-Phthalocyanine as High Performance Liquid Chromatography Stationary Phase

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Effect of alkyl chain length of the stationary phase on retention and selectivity in reversed-phase liquid chromatography

Cited by 114 publications

References 31 publications

Possibilities and pitfalls in defining selectivity in HPLC

Possibilities and pitfalls in defining selectivity in HPLC

Design of C18 Organic Phases with Multiple Embedded Polar Groups for Ultraversatile Applications with Ultrahigh Selectivity

Separation Characteristics of Aminopropyl Silica Gels Modified with Copper-Phthalocyanine as High Performance Liquid Chromatography Stationary Phase

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Design of C₁₈ Organic Phases with Multiple Embedded Polar Groups for Ultraversatile Applications with Ultrahigh Selectivity