1H Magic Angle Spinning NMR Research Articles

Absolute Quantification of Water in Microporous Solids with 1H Magic Angle Spinning NMR and Standard Addition.

Zeolites are microporous materials driving industrial scale adsorption, ion exchange, and catalytic processes. Their water content dramatically impacts their properties, but its quantification with Karl Fisher titration or thermal gravimetric analysis is problematic. When standard addition of water is combined with 1H magic angle spinning (MAS) NMR detection, absolute quantification of water in microporous materials becomes possible. The method was demonstrated on five different, commercially available zeolites.

Hydrogen Bond Networks in Cs2(HSO4)(H2PO4) As Studied by Solid-State NMR

The inorganic solid acid salt Cs2(HSO4)(H2PO4) showed high proton conductivity in the superprotonic phase above 370 K, and the phase was retained on cooling even at room temperature for a long period. These characteristic properties should correlate to the hydrogen bond network connecting the SO4 and PO4 groups. In the present work, the structures of the hydrogen bond network were studied by solid-state NMR. We present 31P, 1H, and 133Cs magic-angle-spinning (MAS) NMR spectra, 31P static NMR spectra to derive chemical shift anisotropy, a 31P{1H} dipolar dephasing experiment, and 1H{31P} rotational-echo double resonance (REDOR) experiments. The 31P NMR spectra indicate that all the P sites are crystallographically equivalent, and the negative value of the chemical shift anisotropy suggests that four hydrogen bonds are formed around the PO4 tetrahedron. The 31P{1H} dipolar dephasing experiment strongly supports that the number of hydrogen bonds around the PO4 tetrahedron is four. The 1H and 133Cs MAS NMR spectra show that a part of the hydrogen bond network is disordered and that the disordered structure relaxes slowly with time. On the basis of those NMR results, we propose a model structure of the hydrogen bond network.

Solid-State 1H and 27Al NMR Studies of DMSO-Kaolinite Intercalates

AbstractNuclear magnetic resonance (NMR) provides a powerful tool to describe local nuclear environments. In this work, unique structural information on kaolinite and on kaolinite dimethylsulfoxide (DMSO) intercalate were provided by solid-state 1H and 27Al magic-angle spinning (MAS) NMR. The interlayer chemistry of kaolinite (K) was examined by intercalating a select group of highly polar organic molecules or salts into kaolinite as a first step. Once the interlayer space is expanded, the intercalated compounds can be replaced in a second step. Intercalating DMSO into kaolinite to form the DMSO-K intercalate is, thus, a particularly useful first step toward the intercalation of a large variety of molecules, including polymers and ionic liquids. Well developed characterization methods are essential to define the structural modifications of kaolinite, and MAS NMR is a useful complement to other techniques. The use of 1H and 27Al MAS NMR for this purpose has been relatively rare. 1H NMR, nevertheless, can give unique information about kaolinite hydroxyls. Because quadrupolar interactions are sensitive to the local octahedral Al(III) geometry, solid-state 27Al NMR can follow subtle structural modifications in the octahedral sheet. In the present work, the 1H MAS NMR chemical shifts of KGa-1b were unambiguously attributed to the internal surface hydroxyls at 2.7 ppm and to the internal hydroxyls at 1.7 ppm. The 1H MAS NMR chemical shifts of the two methyl groups in DMSO-K are not equivalent and can be attributed to the 2.9 and 4.2 ppm peaks. The 27Al MAS NMR spectra of KGa-1b obtained under different magnetic fields revealed that most of the quadrupolar effects were highly reduced at 21.1 T, whereas the spectra at lower field, 4.7 T, were dominated by quadrupolar effects. The two octahedral Al(III) sites are not equivalent and can be distinguished in the low-field spectral simulation. Increased quadrupolar constants were observed and showed the major perturbations of the local Al symmetry that resulted from DMSO intercalation. Both the 1H and 27Al MAS NMR studies at different magnetic fields afforded important information about the local environments of the kaolinite hydroxyl groups and structural Al(III).

Altered hepatic lipid metabolism in mice lacking both the melanocortin type 4 receptor and low density lipoprotein receptor.

Obesity is often associated with dyslipidemia and hepatosteatosis. A number of animal models of non-alcoholic fatty liver disease (NAFLD) are established but they significantly differ in the molecular and biochemical changes depending on the genetic modification and diet used. Mice deficient for melanocortin type 4 receptor (Mc4rmut) develop hyperphagia, obesity, and subsequently NAFLD already under regular chow and resemble more closely the energy supply-driven obesity found in humans. This animal model was used to assess the molecular and biochemical consequences of hyperphagia-induced obesity on hepatic lipid metabolism. We analyzed transcriptome changes in Mc4rmut mice by RNA sequencing and used high resolution 1H magic angle spinning NMR spectroscopy and MALDI-TOF mass spectrometry to assess changes in the lipid composition. On the transcriptomic level we found significant changes in components of the triacylglycerol metabolism, unsaturated fatty acids biosynthesis, peroxisome proliferator-activated receptor signaling pathways, and lipid transport and storage compared to the wild-type. These findings were supported by increases in triacylglycerol, monounsaturated fatty acid, and arachidonic acid levels. The transcriptome signatures significantly differ from those of other NAFLD mouse models supporting the concept of hepatic subphenotypes depending on the genetic background and diet. Comparative analyses of our data with previous studies allowed for the identification of common changes and genotype-specific components and pathways involved in obesity-associated NAFLD.

A combined NMR crystallographic and PXRD investigation of the structure-directing role of water molecules in orotic acid and its lithium and magnesium salts

Despite the abundance of hydrates, their multifaceted nature and hydration/dehydration behaviour is still not fully understood. For the example of orotic acid monohydrate and its lithium and magnesium hydrate salts, we show how NMR crystallography, namely a combination of solid-state NMR with a focus here on 1H magic angle spinning (MAS) NMR experiments and first-principles DFT GIPAW (gauge-including projector augmented wave) calculations, can play a valuable role in the characterization of hydrate systems. Starting from lithium orotate monohydrate, a rigid system with a limited number of tightly bound water molecules, the general feasibility of this approach was demonstrated. Moving onto more complex hydrate structures, mobility in the orotic acid monohydrate was observed, while for the most complex hydrate, magnesium orotate octahydrate, a loss of associated water molecules was observed after an overnight MAS NMR experiment. A combined study by experimental MAS NMR, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA) revealed changes after vacuum drying as well as after storage of a vacuum dried sample under ambient conditions. Specifically, TGA showed the vacuum dried sample to correspond to a dihydrate, for which no structure has yet been determined by single-crystal X-ray diffraction. An NMR crystallography analysis showed that a combination of putative symmetric and asymmetric dihydrate structures explains the observed changes in the experimental MAS NMR spectra.

High-Resolution Structural Characterization of a Heterogeneous Biocatalyst Using Solid-State NMR

Solid-state magic-angle spinning (MAS) NMR spectroscopy was employed to investigate structural detail in the enzyme human carbonic anhydrase II (hCA II) in uniformly 15N and selectively (15N leucine) enriched states, covalently immobilized on epoxy-functionalized silica. The immobilized hCA II retained 71% of its specific enzymatic activity when compared to the free enzyme in solution. On the basis of the one- and two-dimensional 1H, 13C, 15N, and 29Si MAS NMR spectra, chemical shift assignments could be obtained from the silica support, covalent linker, and immobilized enzyme. The successful covalent immobilization of the enzyme on epoxy–silica was confirmed by the appearance of signals from the aromatic and carbonyl groups in the immobilized enzyme in addition to signals from the modified support. Most notably, our MAS NMR results suggest that the covalent immobilization of the hCA II on epoxy–silica does not significantly affect the structural integrity of the protein.

Metabolic profiling of ob/ob mouse fatty liver using HR-MAS 1H-NMR combined with gene expression analysis reveals alterations in betaine metabolism and the transsulfuration pathway.

Metabolic perturbations resulting from excessive hepatic fat accumulation are poorly understood. Thus, in this study, leptin-deficient ob/ob mice, a mouse model of fatty liver disease, were used to investigate metabolic alterations in more detail. Metabolites were quantified in intact liver tissues of ob/ob (n = 8) and control (n = 8) mice using high-resolution magic angle spinning (HR-MAS) 1H-NMR. In addition, after demonstrating that HR-MAS 1H-NMR does not affect RNA integrity, transcriptional changes were measured by quantitative real-time PCR on RNA extracted from the same specimens after HR-MAS 1H-NMR measurements. Importantly, the gene expression changes obtained agreed with those observed by Affymetrix microarray analysis performed on RNA isolated directly from fresh-frozen tissue. In total, 40 metabolites could be assigned in the spectra and subsequently quantified. Quantification of lactate was also possible after applying a lactate-editing pulse sequence that suppresses the lipid signal, which superimposes the lactate methyl resonance at 1.3ppm. Significant differences were detected for creatinine, glutamate, glycine, glycolate, trimethylamine-N-oxide, dimethylglycine, ADP, AMP, betaine, phenylalanine, and uridine. Furthermore, alterations in one-carbon metabolism, supported by both metabolic and transcriptional changes, were observed. These included reduced demethylation of betaine to dimethylglycine and the reduced expression of genes coding for transsulfuration pathway enzymes, which appears to preserve methionine levels, but may limit glutathione synthesis. Overall, the combined approach is advantageous as it identifies changes not only at the single gene or metabolite level but also deregulated pathways, thus providing critical insight into changes accompanying fatty liver disease. Graphical abstract A Evaluation of RNA integrity before and after HR-MAS 1H-NMR of intact mouse liver tissue. B Metabolite concentrations and gene expression levels assessed in ob/ob (steatotic) and ob/+ (control) mice using HR-MAS 1H-NMR and qRT-PCR, respectively.

MAS 1H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS 1H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids’ melting temperature (Tm). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.

In-pore exchange and diffusion of carbonate solvent mixtures in nanoporous carbon

High resolution magic angle spinning (HRMAS) 1H NMR spectroscopy has been used to resolve different surface and in-pore solvent environments of ethylene carbonate (EC) and dimethyl carbonate (DMC) mixtures absorbed within nanoporous carbon (NPC). Two dimensional (2D) 1H HRMAS NMR exchange measurements revealed that the inhomogeneous broadened in-pore resonances have pore-to-pore exchange rates on the millisecond timescale. Pulsed-field gradient (PFG) NMR diffusometry revealed the in-pore self-diffusion constants for both EC and DMC were reduced by up to a factor of five with respect to the diffusion in the non-absorbed solvent mixtures.

Lysine-Capped Silica Nanoparticles: A Solid-State NMR Spectroscopy Study

ABSTRACTTo achieve the goal of biocompatibility in nano-based materials we must first obtain a fundamental understanding of the physical and chemical behavior of biomolecules at the interfaces of nanomaterials. A first step towards understanding protein interactions with nanomaterials is to understand how individual amino acids interact at the interfaces. In this paper, we investigated the lysine adsorption behavior on fumed silica nanoparticles by solid-state NMR spectroscopy. We use 1H, 13C and 15N solid-state magic angle spinning (MAS) NMR techniques to elucidate how lysine is adsorbed on silica nanoparticles surfaces via strong hydrogen-bonding interaction between the protonated side-chain amine group and silanol group on silica nanoparticles surfaces.*

Insight into Hydrogen Bonding of Uranyl Hydroxide Layers and Capsules by Use of 1H Magic-Angle Spinning NMR Spectroscopy

Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. These NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.

Effect of organochlorine pesticides exposure on the maize root metabolome assessed using high-resolution magic-angle spinning 1H NMR spectroscopy

1H-HRMAS NMR-based metabolomics was used to better understand the toxic effects on maize root tips of organochlorine pesticides (OCPs), namely lindane (γHCH) and chlordecone (CLD). Maize seedlings were exposed to 2.5 μM γHCH (mimicking basic environmental contaminations) for 7 days and compared to 2.5 μM CLD and 25 μM γHCH for 7 days (mimicking hot spot contaminations). The 1H-HRMAS NMR-based metabolomic profiles provided details of the changes in carbohydrates, amino acids, tricarboxylic acid (TCA) cycle intermediates and fatty acids with a significant separation between the control and OCP-exposed root tips. First of all, alterations in the balance between glycolysis/gluconeogenesis were observed with sucrose depletion and with dose-dependent fluctuations in glucose content. Secondly, observations indicated that OCPs might inactivate the TCA cycle, with sizeable succinate and fumarate depletion. Thirdly, disturbances in the amino acid composition (GABA, glutamine/glutamate, asparagine, isoleucine) reflected a new distribution of internal nitrogen compounds under OCP stress. Finally, OCP exposure caused an increase in fatty acid content, concomitant with a marked rise in oxidized fatty acids which could indicate failures in cell integrity and vitality. Moreover, the accumulation of asparagine and oxidized fatty acids with the induction of LOX3 transcription levels under OCP exposure highlighted an induction of protein and lipid catabolism. The overall data indicated that the effect of OCPs on primary metabolism could have broader physiological consequences on root development. Therefore, 1H-HRMAS NMR metabolomics is a sensitive tool for understanding molecular disturbances under OCP exposure and can be used to perform a rapid assessment of phytotoxicity.

Metabonomic characteristics and biomarker research of human lung cancer tissues by HR1H NMR spectroscopy.

The combination of NMR spectroscopy and multivariate data analysis (MVDA), such as orthogonal partial least squares-discriminant analysis (OPLS-DA), has been collectively acknowledged as an excellent tool to investigate tissue metabolism and provide metabolite information for the diagnosis of disease, and become an important metabonomic platform for studies in biological tissues so far. Both ex vivo high resolution magic-angle spinning1H NMR and in vitro1H NMR spectroscopy technique were synchronously employed to analyze the metabonomic characteristics of 102 lung tissues from 34 patients with lung cancer in hope to identify potential diagnostic biomarkers for malignancy detection in lung tissues. Significant elevations in the levels of lipids and lactate and significant reductions in the levels of myo-inositol and valine in the cancer tissues had been identified when compared with the adjacent non-involved tissues. Furthermore, the OPLSDA models calculated by two1H NMR spectra provided for relatively high sensitivity, specificity and good prediction accuracy in the identification of class membership regardless of the number of metabolites involved. MVDA in combination with1H NMR spectra highlighted the potential of metabonomics in clinical settings so that the techniques might be further exploited for future lung cancer biomarker research or identification.

Discrimination of Basal Cell Carcinoma from Normal Skin Tissue Using High-Resolution Magic Angle Spinning 1H NMR Spectroscopy.

High-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy is a useful tool for investigating the metabolism of various cancers. Basal cell carcinoma (BCC) is the most common skin cancer. However, to our knowledge, data on metabolic profiling of BCC have not been reported in the literature. The objective of the present study was to investigate the metabolic profiling of cutaneous BCC using HR-MAS 1H NMR spectroscopy. HR-MAS 1H NMR spectroscopy was used to analyze the metabolite profile and metabolite intensity of histopathologically confirmed BCC tissues and normal skin tissue (NST) samples. The metabolic intensity normalized to the total spectral intensities in BCC and NST was compared, and multivariate analysis was performed with orthogonal partial least-squares discriminant analysis (OPLS-DA). P values < 0.05 were considered statistically significant. Univariate analysis revealed 9 metabolites that showed statistically significant difference between BCC and NST. In multivariate analysis, the OPLS-DA models built with the HR-MAS NMR metabolic profiles revealed a clear separation of BCC from NST. The receiver operating characteristic curve generated from the results revealed an excellent discrimination of BCC from NST with an area under the curve (AUC) value of 0.961. The present study demonstrated that the metabolite profile and metabolite intensity differ between BCC and NST, and that HR-MAS 1H NMR spectroscopy can be a valuable tool in the diagnosis of BCC.

Tissue Metabonomic Phenotyping for Diagnosis and Prognosis of Human Colorectal Cancer.

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide and prognosis based on the conventional histological grading method for CRC remains poor. To better the situation, we analyzed the metabonomic signatures of 50 human CRC tissues and their adjacent non-involved tissues (ANIT) using high-resolution magic-angle spinning (HRMAS) 1H NMR spectroscopy together with the fatty acid compositions of these tissues using GC-FID/MS. We showed that tissue metabolic phenotypes not only discriminated CRC tissues from ANIT, but also distinguished low-grade tumor tissues (stages I-II) from the high-grade ones (stages III-IV) with high sensitivity and specificity in both cases. Metabonomic phenotypes of CRC tissues differed significantly from that of ANIT in energy metabolism, membrane biosynthesis and degradations, osmotic regulations together with the metabolism of proteins and nucleotides. Amongst all CRC tissues, the stage I tumors exhibited largest differentiations from ANIT. The combination of the differentiating metabolites showed outstanding collective power for differentiating cancer from ANIT and for distinguishing CRC tissues at different stages. These findings revealed details in the typical metabonomic phenotypes associated with CRC tissues nondestructively and demonstrated tissue metabonomic phenotyping as an important molecular pathology tool for diagnosis and prognosis of cancerous solid tumors.

Quantitative analyses of PEGylated phospholipids adsorbed on single walled carbon nanohorns by high resolution magic angle spinning 1H NMR

Adsorption of polyethylene glycol conjugated phospholipids with various PEG chain length (DSPE-PEG5000, 2000, 750) onto single-walled carbon nanohorns (SWCNH), a type of graphene nano-tubule, in aqueous solution was investigated by means of high-resolution magic angle spinning (HRMAS) 1H NMR. Peak integral ratio of PEG chains and alkyl chains of DSPE-PEGs in the NMR spectra linearly decreased to zero with the increase of SWCNH quantity, indicating that the adsorption of DSPE-PEGs on SWCNH was virtually irreversible. The area of SWCNH surface allocated to the individual DSPE-PEG5000, 2000, 750 molecule were estimated to be 7.06, 5.18, and 4.45 nm2, respectively. Coverages of the alkyl chains on the surface area of SWCNH were about 28%, 39% for DSPE-PEG5000, 2000 and 46% for DSPE-PEG750, suggesting single layer adsorption. We presumed that the electrostatic repulsion may prevent DSPE-PEGs from multiple layer and keep away neighbouring DSPE-PEGs on the surface. According to the molecular areas of the DSPE-PEGs, PEG5000 and 2000 chains were considered to be in brush-regimes, while PEG750 was considered to be in mushroom regime on the SWCNH surface.

Nuclear Overhauser effect as a probe of molecular structure, dynamics and order of axially reorienting molecules in membranes

The location, orientation, order and dynamics of cholesterol in model membranes have been well characterized, therefore cholesterol is an ideal molecule for developing new methods for studying structured molecules undergoing rapid axially symmetric reorientation. The use of 13C filtering via short contact cross polarization transfer to 1H allows the recovery of the weak cholesterol 1H magic angle spinning NMR signals from beneath the strong phospholipid background in bicelles composed of chain perdeuterated dimyristoyl phosphatidylcholine/dicaproyl phosphatidylcholine/[3,4-13C]-cholesterol. Measurements of the nuclear Overhauser enhancement for 1H nuclei located in the first ring of cholesterol are interpreted in terms of a simple two motion model consisting of axial reorientation, with a correlation time τ∥, and a slower reorientation of the diffusion axis relative to the bilayer normal, with correlation time τ⊥. This approach can be extended to other molecules which undergo rapid axial reorientation such as small membrane associated peptides.

Mechanism of calcite wettability alteration by alkyl polyglucoside

Surfactant injection into oil-wet carbonate reservoirs offers a large potential for increased oil recovery due to reservoir wettability alterations. Here, the mechanism of wettability alteration by non-ionic surfactant alkyl polyglucoside (APG) is investigated and compared to that of the cationic surfactant dodecyltrimethylammonium bromide (DTAB). Techniques used include 1H and 13C magic angle spinning NMR, zeta potential, adsorption and contact angle (CA) measurements. APG monomers effectively desorb stearic acid (SA) from an SA treated calcite surface by replacing it at cationic sites on the surface, both above and below the APG critical micelle concentration (CMC). Increased polarization of the APG hydroxyl groups upon interaction with Ca+ sites is a driving force for APG adsorption. CAs show that APG treatment changes wettability to water-wet both below (CA = 66.9°) and above (CA = 77.2°) CMC. An observed sphere-to-rod transition occurring in APG solution above 1 mM is accompanied by a structural transition from half-micelles to patches of partial bilayers at the calcite surface, which further increases APG adsorption and CA (CA = 88.1°). In the presence of SA, adsorption of APG onto calcite is similar to that of DTAB below CMC, while above CMC APG adsorption is 2–3 times higher than DTAB. In absence of SA, DTAB adsorption is negligible. CAs are comparable after APG and DTAB treatment, making APG an interesting candidate for such purposes due to its effectiveness at very low concentrations.

The use of a selective saturation pulse to suppress t1 noise in two-dimensional 1H fast magic angle spinning solid-state NMR spectroscopy

A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+kHz) suppresses t1 noise in the indirect dimension of two-dimensional 1H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl 1H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion – this is quantified by comparing two-dimensional 1H NOESY-like spin diffusion spectra recorded at 30–70kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30ms and nutation frequency 725Hz at 70kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear 1H–1H double quantum (DQ)/single quantum (SQ) MAS and 14N–1H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.

High-Density Octadecyl Chemically Bonded Core–Shell Silica Phases for HPLC: Comparison of Microwave-Assisted and Classical Synthetic Routes, Structural Characterization and Chromatographic Evaluation

In this study, different grafting methods were examined to develop high-density chemically modified octadecyl core–shell silica particles for HPLC applications. The influence of the reagents and the experimental conditions were evaluated, either through conventional heating or by microwave irradiation. For both experimental synthetic processes, chemically bonded phases were prepared by grafting the functionalized silane (octadecyldimethylchlorosilane or octadecyldimethyl(dimethylamino)silane) and, on the other hand, using a hydrosilylation procedure. The bonded silica phases were fully characterized by elemental analysis, diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy, 29Si cross-polarization magic angle spinning NMR and 1H magic angle spinning NMR; and the granulometric distribution was evaluated by SEM. The maximum grafting rate (4.4 µmol m−2) was determined by direct silanization with hexamethyldisilazane. The best grafting rate (3.8 µmol m−2) for octadecyl functionalization was obtained using octadecyldimethyl(dimethylamino)silane. The Tanaka test was used to estimate the chromatographic behavior of the overall set of synthesized bonded stationary phases, and their chromatographic performances were compared with similar columns available on the market. In this article, we used microwave irradiation methods to drastically reduce the reaction time for a comparable grafting rate and equivalent chromatographic performances.