Polarity of chemically modified silica surfaces and its dependence on mobile-phase composition by fluorescence spectrometry

Staahlberg, Jan.; Almgren, Mats

doi:10.1021/ac00281a010

Cited by 95 publications

(53 citation statements)

References 24 publications

(43 reference statements)

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“…Conversely, a high correlation between these results occurs when MeOH is employed [14,16,17]. The adsorption isotherms reported for RP-HPLC systems using water-methanol mixtures indicate that the compositions of alkyl-bonded stationary phases remain fairly constant in the range 0.2 < ϕ < 0.8 [18,19]. The above pore exclusion effect, also observed in the non-linear portion, is currently attributed to the presence of not-alkylated silanols onto the packing material.…”

Section: Introductionmentioning

confidence: 95%

Derived chromatographic indices as effective tools to study the self-aggregation process of bile acids

Natalini

Sardella

Camaioni

et al. 2009

Journal of Pharmaceutical and Biomedical Analysis

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Section: Introductionmentioning

confidence: 95%

Derived chromatographic indices as effective tools to study the self-aggregation process of bile acids

Natalini

Sardella

Camaioni

et al. 2009

Journal of Pharmaceutical and Biomedical Analysis

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“…This methodology is typically applied to solutions, either liquid or solid. Application to interfaces to determine surface polarity has also been reported. − However, the structure of many fluorophores is dependent on the thickness or surface concentration, , which can mask the interpretation of the substrate properties. The xanthene dyes are examples of this because they are susceptible to dimerization and higher-order aggregation, both of which have a significant effect on the photophysics of the dye. − The focus in this Article will be the use of rhodamine 6G (Rh6G), a xanthene dye used for a variety of applications, − to study the surface properties of poly(vinylidene difluoride) (PVDF).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Interfacial Effects on the Photophysics of Rhodamine 6G Thin Films on a Poly(vinylidene fluoride) Surface

Mullen

Euler

2017

Langmuir

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The spectral response of ultrathin films of rhodamine 6G (Rh6G) cast onto polyvinylidenefluoride (PVDF) coated glass slides is studied to investigate a perceived fluorescence emission enhancement. Varying the thickness of the Rh6G layer (submonolayer to multiple layers) on the PVDF layer revealed the existence of multiple Rh6G species on the surface, similar to previous reports on glass. Excitation spectra show that J-type excitons are not responsible for an emission enhancement. Trends in the fluorescence emission intensity show that the surface roughness of the PVDF layer prevents the Rh6G molecules from organizing the way they would on a smooth glass surface. The PVDF surface roughness preserves the emissive monomers and excited-state excimers of Rh6G while reducing the self-quenching of aggregates. Coupled with this is an internal reflection effect that causes light to be trapped between the Rh6G/PVDF and PVDF/glass interfaces. This effect leads to multiple absorption events, and thus more efficient use of the incident light.

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“…The use of fluorescence to characterize silica surfaces is well-documented, especially for silica-based materials in chromatography. Specifically, fluorescence-based experiments on covalently attached [42][43][44][45][46][47][48][49][50][51][52][53][54] or physiosorbed probes [55][56][57][58][59][60][61][62][63] have been carried out to gain a better understanding of the accessibility, distribution, mobility, and orientation of surface-bound molecules (e.g., catalysts, ligands, reagents, and recognition elements).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Dansylated Aminopropyl Controlled Pore Glass Solvated by Molecular and Ionic Liquids

et al. 2006

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We compare how (i) four ionic liquids (ILs) (1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpy][Tf2N]), and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P(C6)3C14][Tf2N])) and (ii) two conventional molecular liquids (methanol and 1-octanol) solvate/wet luminescent organic moieties that are covalently attached to the surface of silica controlled pore glass (CPG). A series of aminopropyl CPG particles that have been covalently tagged with the solvatochromic fluorescent probe group dansyl were used in this study. The results demonstrate that ILs solvate/wet the silica surface differently in comparison to molecular liquids (MLs). Specifically, when comparing ILs and MLs that appear to solvate the free probe, dansylpropylsulfonamide (DPSA), equally in solution, we find that ILs do not solvate/wet the silica surfaces as well as the corresponding MLs. The cation component in these ILs is the significant factor in how the ILs solvate/wet silica surfaces. Solvation/wetting of surface-bound species at a silica surface depends on the cation size. Chlorosilane end-capping of the surface silanol and amine residues attenuates the cation's affects.

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Polarity of chemically modified silica surfaces and its dependence on mobile-phase composition by fluorescence spectrometry

Cited by 95 publications

References 24 publications

Derived chromatographic indices as effective tools to study the self-aggregation process of bile acids

Derived chromatographic indices as effective tools to study the self-aggregation process of bile acids

The Influence of Interfacial Effects on the Photophysics of Rhodamine 6G Thin Films on a Poly(vinylidene fluoride) Surface

Comparison of Dansylated Aminopropyl Controlled Pore Glass Solvated by Molecular and Ionic Liquids

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