Literature

With extensive experience and after much research, the Diamond Analytics team publishes several papers in leading industry journals

Literature

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Evaluation of a new wide-pore superficially porous material with carbon core and nanodiamond-polymer


Evaluation of a new wide-pore superficially porous material with carbon core and nanodiamond-polymer

In this study, reversed phase liquid chromatographic columns packed with superficially porous material made of a carbon core and nanodiamond-polymer shell were evaluated for the analytical characterization of proteins. The emphasis was put on the impact of pore size on the kinetic performance when analyzing large molecules. Three different types of columns possessing an average pore size of 120, 180, and 250 Å were thus evaluated. As expected, the peak capacities were improved with the 180 and above all the 250 Å pore size, while the kinetic performance achieved with the 120 Å were systematically lower.

Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography


Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography

Microfabrication of ultrathin-layer chromatography (UTLC) plates via conformal deposition of silicon nitride by low-pressure chemical vapor deposition onto patterned carbon nanotube (CNT) scaffolds was demonstrated. After removal of the CNTs and hydroxylation, the resulting UTLC phase showed no expansion or distortion of their microfeatures and the absence/reduction of remaining nitrogenic species. Developing time of a mixture of lipophilic dyes on this UTLC plates was 86% shorter than on high-performance thin-layer chromatography (HPTLC) plates. A water-soluble food dye mixture was also separated resulting in low band broadening and reduced developing time compared to HPTLC. For the latter example, mobile phase optimization on a single UTLC plate consisted of 14 developments with different mobile phases, each preceded by a plate prewashing step. The same plate was again reused for additional 11 separations under varying conditions resulting in a development procedure with a mean separation efficiency of 233,000 theoretical plates/m and a reduced mobile phase consumption of only 400 μL. This repeated use proved the physical robustness of the ultrathin layer and its resistance to damage. The layer was highly suited for hyphenation to ambient mass spectrometry, including desorption electrospray ionization (DESI) mass spectrometry imaging and direct analysis in real time (DART) mass spectrometry.

Multi-Instrument Characterization of Poly(Divinylbenzene) Microspheres for Use in Liquid Chromatogra

We report a multi-instrument characterization of the carbon particles in carbon/polymer/nanodiamond core-shell materials used for high-performance liquid chromatography. These particles are prepared by the carbonization/pyrolysis of

Multi-Instrument Characterization of Poly(Divinylbenzene) Microspheres for Use in Liquid Chromatography: As Received, Air Oxidized, Carbonized, and Acid Treated

Separation of Cannabinoids on Three Different Mixed-Mode Columns Containing Carbon/Nanodiamond/Amine

Three   mixedmode   HPLC   columns   packed   with   superficially   porous carbon/nanodiamond/aminepolymer particles were used to separate mixtures of cannabinoids. Columns evaluated included: (i) reversed phase (C18), weak anion exchange, 4.6 x 33 mm, 3.6 Bm, and 4.6 x 100 mm, 3.6 Bm, (ii) reversed phase, strong anion exchange (quaternary amine), 4.6 x 33 mm, 3.6 Bm, and (iii) hydrophilic interaction liquid chromatography, 4.6 x 150 mm, 3.6 Bm.  Different selectivities were achieved under various mobile phase and stationary phase conditions. Efficiencies and peak capacities were as high as 54,000 N/m and 56, respectively. The reversed phase mixedmode column (C18) retained tetrahydrocannabinolic acid strongly under acidic conditions and weakly under basic conditions. Tetrahydrocannabinolic acid was retained strongly on the reversed phase, strong anion exchange mixedmode column under basic polar organic mobile phase conditions.  The hydrophilic interaction liquid chromatography column retained polar cannabinoids better than the (more) neutral ones under basic conditions. A longer reversed phase (C18) mixedmode column (4.6 x 100 mm) showed better resolution for analytes (and a contaminant) than a shorter column. Fast separations were achieved in less than five minutes and sometimes two minutes. A real world sample (bubble hash extract) was also analyzed by gradient elution.

Superficially porous particles with carbon core and nanodiamond–polymer shell for protein separati


Superficially porous particles with carbon core and nanodiamond–polymer shell for protein separati


JPBAPowerpoint slides from the presentation provided by Szabolcs FEKETE, Davy GUILLARME at Pittcon 2015

Evaluation of new superficially porous nanodiamond–polymer shell for proteins characterization


JPBAA new superficially porous material possessing a carbon core and nanodiamond–polymer shell and pore size of 180 A ̊ was evaluated for the analysis of large proteins. Because the stationary phase on this new support contains a certain amount of protonated amino groups within the shell structure, the resulting retention mechanism is most probably a mix between reversed phase and anion exchange. However, under the applied conditions (0.1–0.5% TFA in the mobile phase), it seemed that the main retention mechanism for proteins was hydrophobic interaction with the C18 alkylchains on this carbon based material.


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Core-Shell Diamond as a Support for Solid-Phase Extraction and HPLC


JPC MagazineWe report the formation of core-shell diamond particles for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond.


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Amino-Modified Diamond as a Durable Stationary Phase for Solid-Phase Extraction


Amino-Modified Diamond as a Durable Stationary Phase for Solid-Phase Extraction

We report the formation of a highly stable amino stationary phase on diamond and demonstrate its use in solid-phase extraction (SPE). This process consists of spontaneous and self-limiting adsorption of polyallylamine (PAAm) from aqueous solution onto oxidized diamond. Thermal curing under reduced pressure or chemical cross-linking with a diepoxide was shown to fix the polymer to the particles.


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Pellicular Particles with Spherical Carbon Cores and Porous Nanodiamond Shell for RP HPLC


Analytical ChemistrySilica is the workhorse of modern liquid chromatography because of its broad array of available functionalities. However, despite its flexibility, common silica-based stationary phases lack stability at both high and low pH.

Nanodiamond, if used in liquid chromatography, has been found to eradicate the lack of stability on both ends of the pH scale while keeping the broad array of functionality of silica.

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Direct modification of hydrogen/deuterium-terminated diamond particles


Analytical Chemistry

We describe direct polymer attachment to hydrogen and deuterium-terminated diamond (HTD and DTD) surfaces using a radical initiator (di-tert-amyl peroxide, DTAP), a reactive monomer (styrene) and a crosslinking agent (divinylbenzene, DVB) to create polystyrene encapsulated diamond. Chemisorbed polystyrene is sulfonated with sulfuric acid in acetic acid. Surface changes were followed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). Finally, both polystyrene-modified DTD and sulfonated styrene-modified DTD were used in solid phase extraction (SPE). Percent recovery and column capacity were investigated for both phenyl (polystyrene) and sulfonic acid treated polystyrene SPE columns. These diamond-based SPE supports are stable under basic conditions, which is not the case for silica-based SPE supports.


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Improvements in the Chromatographic Properties of Porous Graphitic Carbon


Hypercarb™ involves the use of a radical-producing reagent that is believed to induce grafting to the surface of PGC, leading to an increase in separation efficiency, reduction in peak asymmetry and a slight decrease in retention factors.



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CNT-Templated Microfabrication of Porous Silicon-Carbon Materials


CNT-Templated Microfabrication of Porous Silicon-Carbon Materials

Several functional properties of materials are impacted by the three dimensional shape of the material on both the micrometer scale(microscale) and nanometer scale(nanoscale). Microscale patterning of a material affects several functional properties including fluid flow, ion and electron conductivity, mechanical response, and interactions with electromagnetic fields and waves.


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Introduction to XPS Characterization of Materials in Novel CNT-Based, Microfabricated TLC Plates


Several functional properties of materials are impacted by the three dimensional shape of the material on both the micrometer scale(microscale) and nanometer scale(nanoscale). Microscale patterning of a material affects several functional properties including fluid flow, ion and electron conductivity, mechanical response, and interactions with electromagnetic fields and waves.


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ALD of Aluminum-Free Silica onto Patterned CNT Forests in the preparation of M-TLC Plates


JPC Diamond AnalyticsWe describe the direct, conformal, atomic layer deposition (ALD) of silica onto carbon nanotubes (CNTs) in the microfabrication of thin-layer chromatography (TLC) plates. As before, these plates were prepared with zig-zag hedge and channel microstructures, with high aspect ratio, porous hedges. After ALD, scanning electron microscopy (SEM) showed an increase in the radius of the CNTs of 8–40 nm. X-ray photoelectron spectroscopy (XPS) showed that the plates were composed almost entirely of silicon and oxygen, without contamination of metals or other elements that might compromise chromatographic performance, e.g., aluminum.

To check out JPC’s writeup, click here.