Chromatographic properties of hydrogenated microdiamond synthesized by high pressure and high temperature.

Adsorption and chromatographic properties of oxidized and hydrogenated 'high pressure and high temperature' synthesised diamond (HPHT) are studied using high-performance liquid chromatography. The retention factors of organic cation (benzyltributylammonium chloride), weak base (aniline), weak acid (benzoic acid), strong acid (benzenesulfonic acid), hydrophobic toluene, and hydrophilic uracil are obtained at varied pH, organic solvent content, and ionic strength of mobile phase. Both adsorbents exhibited moderate polarity with a mixed-mode retention mechanism with a combination of electrostatic, hydrophobic and hydrophilic interactions.

Recent advances and applications of synthetic diamonds in solid-phase extraction and high-performance liquid chromatography.

Since the advent of diamond-based adsorbents in the late 1960s, the interest in their use for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) has steadily increased. This is primarily due to their unique properties, such as extreme chemical and thermal stability, high mechanical strength and biocompatibility, and complex mixed-mode retention mechanisms. Currently, the most commonly used synthetic diamonds in SPE and HPLC are detonation nanodiamonds (DND), high-pressure high-temperature (HPHT) diamonds, and chemical vapour deposition (CVD) diamonds.

Ion chromatographic determination of hydrazine in excess ammonia for monitoring graphene oxide reduction reaction.

A new ion chromatography method has been developed to study graphene oxide (GO) reduction by monitoring hydrazine concentration in the GO suspension. The method is based on ion chromatographic separation of hydrazine (from excess ammonia) and its selective determination by electrochemical detection. The developed analytical protocol overcame the significant practical challenges of atmospheric hydrazine oxidation and minimised the matrix interference in both separation and detection which result from the excess of ammonium with respect to hydrazine (up to 5.

Chromatographic behaviour of synthetic high pressure high temperature diamond in aqueous normal phase chromatography.

The chromatographic properties of high pressure high temperature synthesised diamond (HPHT) are investigated under the conditions of hydrophilic interaction liquid chromatography (HILIC). A 50×4.6mm ID stainless steel column packed with HPHT particles of mean diameter 1.

Flow-dependent separation selectivity for organic molecules on metal-organic frameworks containing adsorbents.

A new flow-dependent separation selectivity (FDSS) effect was discovered in isocratic HPLC. Significant changes in chromatographic selectivity were achieved by simple variation of the mobile phase flow rate. The FDSS effect was observed for a core-shell stationary phase using silica particles as a core and a Zr-based metal-organic framework (UiO-66) as a shell.

Chromatographic performance of synthetic polycrystalline diamond as a stationary phase in normal phase high performance liquid chromatography.

The chromatographic properties of high pressure high temperature synthesised diamond (HPHT) are investigated in normal phase mode of high performance liquid chromatography. Purified nonporous irregular shape particles of average particles size 1.2 μm and specific surface area 5.

The importance of chain length for the polyphosphate enhancement of acidic potassium permanganate chemiluminescence.

Sodium polyphosphate is commonly used to enhance chemiluminescence reactions with acidic potassium permanganate through a dual enhancement mechanism, but commercially available polyphosphates vary greatly in composition. We have examined the influence of polyphosphate composition and concentration on both the dual enhancement mechanism of chemiluminescence intensity and the stability of the reagent under analytically useful conditions. The average chain length (n) provides a convenient characterisation, but materials with similar values can exhibit markedly different distributions of phosphate oligomers.

Diamond based adsorbents and their application in chromatography.

The idea of using diamond and diamond containing materials in separation sciences has attracted a strong interest in the past decade. The combination of a unique range of properties, such as chemical inertness, mechanical, thermal and hydrolytic stability, excellent thermal conductivity with minimal thermal expansion and intriguing adsorption properties makes diamond a promising material for use in various modes of chromatography. This review summarises the recent research on the preparation of diamond and diamond based stationary phases, their properties and chromatographic performance.