Comparison of the acidity of residual silanol groups in several liquid chromatography columns

Méndez, Alberto; Bosch, Elisabeth; Rosés, Martı́; Neue, Uwe D.

doi:10.1016/s0021-9673(02)01899-x

Cited by 212 publications

(149 citation statements)

References 12 publications

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“…The available redundant information provides excellent guidance to build realistic surface models that are essential for predictive simulations ( Figure 1 and Supporting Information). [50][51][52][53][67][68][69][70][71] As an example, the sensitivity of surface ionization is graphically illustrated for common amorphous silica nanoparticles prepared by Stöber-like synthesis ( Figure 2). …”

Section: A Silica Surface Model Databasementioning

confidence: 99%

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

et al. 2014

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Silica nanostructures find applications in drug delivery, catalysis, and composites, however, understanding of the surface chemistry, aqueous interfaces, and biomolecule recognition remain difficult using current imaging techniques and spectroscopy. A silica force field is introduced that resolves numerous shortcomings of prior silica force fields over the last thirty years and reduces uncertainties in computed interfacial properties relative to experiment from several 100% to less than 5%. In addition, a silica surface model database is introduced for the full range of variable surface chemistry and pH (Q 2 , Q 3 , Q 4 environments with adjustable degree of ionization) that have shown to determine selective molecular recognition. The force field enables accurate computational predictions of aqueous interfacial properties of all types of silica, which is substantiated by extensive comparisons to experimental measurements. The parameters are integrated into multiple force fields for broad applicability to biomolecules, polymers, and inorganic materials (AMBER, CHARMM, COMPASS, CVFF, PCFF, INTERFACE force field).We also explain mechanistic details of molecular adsorption of water vapor, as well as significant variations in the amount and dissociation depth of superficial cations at silica-water interfaces that correlate with zeta-potential measurements and create a wide range of aqueous environments for adsorption and self-assembly of complex molecules. The systematic analysis of binding conformations and adsorption free energies of distinct peptides to silica surfaces is reported separately in a companion paper. The models aid to understand and design silica nanomaterials in 3D atomic resolution, and are extendable to chemical reactions.

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Section: A Silica Surface Model Databasementioning

confidence: 99%

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

et al. 2014

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“…We can therefore assume that the lower and longer horizontal plateau reflects the titration process of silanol functional groups on the SiO2 surface, and the upper plateau corresponds to silandiol groups. According to (Méndez et al, 2003), the intervals of changes in the dissociation constants are рК1 = 3.51-4.65 and рК2 = 6.17-6.84, respectively. The same values of constants of dissociation for silanol and silandiol groups of silica were measured and published in (Nawrocki, 1997 ;Neue, 2000).…”

Section: Pure Oxidesmentioning

confidence: 99%

pH-Sensitive Nitroxide Radicals for Studying Inorganic and Organo-Inorganic Materials and Systems

Kovaleva¹,

Молочников²

2012

Nitroxides - Theory, Experiment and Applications

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“…On drying, several of the colloidal particles cohere and form particles with surface OH groups. The surface hydroxyl groups are polarised due to hydrogen bondings and the silanol groups exhibit different degrees of acidity [1,2]. The acidic nature of the silanol groups are responsible for the adsorption properties of silica gel and used in the separation of polar compounds.…”

Section: Introductionmentioning

confidence: 99%

The Nature of Rest Silanol Groups on the Surfaces of Silica Based Solid Phase Extraction Materials

Christy

2013

AMR

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Abstract. Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation of compounds. Some commercially available solid phase extraction (SPE) materials based on silica gel were analysed for rest silanol groups by near infrared spectroscopy. The combination frequency of the water molecules in the 5500-5000 cm -1 region was used in identifying the nature of water molecules on the surface and the information was used to identify the types of silanol groups on the surface. Second derivative technique was employed in the detailed analysis.Nine different SPE materials including C18, C8, C 6 H 5 , NH 2 , OH, CN, SiOH, SA (SCX) and SB (SAX) were examined by near infrared spectroscopy for rest silanol groups. The results show that the non-polar and polar stationary phases contain vicinal silanol groups and the ion exchange solid phase materials contain free, vicinal and geminal silanol groups. IntroductionSolid phase extraction (SPE) columns are important tools of an analytical chemist in pre-concentrating analyte from solutions containing the analyte. The separation is carried out by passing the solution containing the component of interest through a column containing a suitable SPE material. When suitable SPE material used, the separation is based on the fact that the solid phase has greater affinity to the solute or components a chemist wants to separate from the solution matrix. This fact helps a chemist to preconcentrate either analyte from a solution matrix (isolation) or get rid of unwanted components (interference retention) in the solution matrix so that the filtrate is free from interfering components in the determination of the analyte. When the retained components on the SPE material are of interest then the components are eluted from the stationary SPE material using a suitable eluent (elution). Solid phase extraction is very widely used in isolating the analyte of interest from a variety of samples such as urine, blood serum, water etc. The mechanism of interaction of the components in the solution matrix and the solid stationary phase includes non polar, polar interactions, van der Waals interactions etc.

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Comparison of the acidity of residual silanol groups in several liquid chromatography columns

Cited by 212 publications

References 12 publications

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

pH-Sensitive Nitroxide Radicals for Studying Inorganic and Organo-Inorganic Materials and Systems

The Nature of Rest Silanol Groups on the Surfaces of Silica Based Solid Phase Extraction Materials

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