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Professor David McCalley's Outputs (65)

The impact of pressure and frictional heating on retention, selectivity and efficiency in ultra-high-pressure liquid chromatography (2014)
Journal Article

© 2014 Elsevier B.V. The effects of pressure and frictional heating deserve serious consideration in ultra-high-pressure liquid chromatography (UHPLC) separations, as the pressures used can be three times greater than those in conventional high-perfo... Read More about The impact of pressure and frictional heating on retention, selectivity and efficiency in ultra-high-pressure liquid chromatography.

Effect of pressure on the selectivity of polymeric C18 and C30 stationary phases in reversed-phase liquid chromatography. Increased separation of isomeric fatty acid methyl esters, triacylglycerols, and tocopherols at high pressure (2014)
Journal Article

A high-density, polymeric C18 stationary phase (Inertsil ODS-P) or a polymeric C30 phase (Inertsil C30) provided improved resolution of the isomeric fatty acids (FAs), FA methyl esters (FAMEs), triacylglycerols (TAGs), and tocopherols with an increas... Read More about Effect of pressure on the selectivity of polymeric C18 and C30 stationary phases in reversed-phase liquid chromatography. Increased separation of isomeric fatty acid methyl esters, triacylglycerols, and tocopherols at high pressure.

Comparison of peak shape in hydrophilic interaction chromatography using acidic salt buffers and simple acid solutions (2014)
Journal Article

The retention and peak shape of neutral, basic and acidic solutes was studied on hydrophilic interaction chromatography (HILIC) stationary phases that showed both strong and weak ionic retention characteristics, using aqueous-acetonitrile mobile phas... Read More about Comparison of peak shape in hydrophilic interaction chromatography using acidic salt buffers and simple acid solutions.

Comparison of the kinetic performance and retentivity of sub-2μm core-shell, hybrid and conventional bare silica phases in hydrophilic interaction chromatography (2014)
Journal Article

© 2014 Elsevier B.V. The separation performance and retention properties of four sub-2μm underivatised silica materials were evaluated in the hydrophilic interaction chromatography (HILIC) mode. These included an organic/inorganic hybrid silica, conv... Read More about Comparison of the kinetic performance and retentivity of sub-2μm core-shell, hybrid and conventional bare silica phases in hydrophilic interaction chromatography.

Practical observations on the performance of bare silica in hydrophilic interaction compared with C18 reversed-phase liquid chromatography (2013)
Journal Article

The kinetic performance of a bare silica and C18 phase prepared from the same sub-2. μm and 3.5. μm base materials were compared in the HILIC and RP mode using both charged and neutral solutes. The HILIC column was characterised using the neutral sol... Read More about Practical observations on the performance of bare silica in hydrophilic interaction compared with C18 reversed-phase liquid chromatography.

Influence of phase type and solute structure on changes in retention with pressure in reversed-phase high performance liquid chromatography (2013)
Journal Article

The influence of pressure on the retention of several types of solute, including acids, bases and neutrals, was studied by the use of restriction capillaries added to the end of various monomeric and polymeric octadecylsilyl-modified 5. μm particle s... Read More about Influence of phase type and solute structure on changes in retention with pressure in reversed-phase high performance liquid chromatography.

Practical investigation of the factors that affect the selectivity in hydrophilic interaction chromatography (2013)
Journal Article

Retention data for a series of 29 compounds comprising acids, bases and neutrals were obtained on six different hydrophilic interaction (HILIC) columns including bare silica, zwitterionic and those bonded with neutral bonded ligands. The principal ai... Read More about Practical investigation of the factors that affect the selectivity in hydrophilic interaction chromatography.

The effect of pressure and mobile phase velocity on the retention properties of small analytes and large biomolecules in ultra-high pressure liquid chromatography (2012)
Journal Article

A possible complication of ultra-high pressure liquid chromatography (UHPLC) is related to the effect of pressure and mobile phase velocity on the retention properties of the analytes. In the present work, numerous model compounds have been selected... Read More about The effect of pressure and mobile phase velocity on the retention properties of small analytes and large biomolecules in ultra-high pressure liquid chromatography.

A comparison of overload behaviour for some sub 2μm totally porous and sub 3μm shell particle columns with ionised solutes (2012)
Journal Article

The overloading performance of some 2.7 μm shell and sub 2 μm totally porous columns, including one pair manufactured from similar materials with similar bonding chemistries, was compared using strongly acidic and basic probe compounds. In general, t... Read More about A comparison of overload behaviour for some sub 2μm totally porous and sub 3μm shell particle columns with ionised solutes.

Determination of catecholamines in urine using hydrophilic interaction chromatography with electrochemical detection (2011)
Journal Article

The determination of catecholamines in urine was investigated using hydrophilic interaction chromatography (HILIC) as an alternative to the commonly used reversed-phase (RP) method. A number of different approaches were explored, including per-aqueou... Read More about Determination of catecholamines in urine using hydrophilic interaction chromatography with electrochemical detection.

Some practical comparisons of the efficiency and overloading behaviour of sub-2μm porous and sub-3μm shell particles in reversed-phase liquid chromatography (2011)
Journal Article

At their optimum flow, sub-3 μm superficially porous or " shell" particles demonstrate similar efficiency to sub-2 μm totally porous particles. The performance of 0.21. cm i.d shell columns is however inferior to those of 0.46. cm i.d., presumably du... Read More about Some practical comparisons of the efficiency and overloading behaviour of sub-2μm porous and sub-3μm shell particles in reversed-phase liquid chromatography.

Instrumental considerations for the effective operation of short, highly efficient fused-core columns. Investigation of performance at high flow rates and elevated temperatures (2010)
Journal Article

Fused core or superficially porous columns offer the advantages of higher efficiency compared with totally porous columns of the same particle size, but similar operating pressures. However, their performance may be adversely affected by extra-column... Read More about Instrumental considerations for the effective operation of short, highly efficient fused-core columns. Investigation of performance at high flow rates and elevated temperatures.

Study of the selectivity, retention mechanisms and performance of alternative silica-based stationary phases for separation of ionised solutes in hydrophilic interaction chromatography (2010)
Journal Article

The separation of a mixture of neutral, strongly acidic and strongly basic compounds was studied in hydrophilic interaction chromatography using a bare silica phase, and bonded silica phases with diol, zwitterionic, amide and hydrophilic/hydrophobic... Read More about Study of the selectivity, retention mechanisms and performance of alternative silica-based stationary phases for separation of ionised solutes in hydrophilic interaction chromatography.

The challenges of the analysis of basic compounds by high performance liquid chromatography: Some possible approaches for improved separations (2010)
Journal Article

This review considers some of the difficulties encountered with the analysis of ionised bases using reversed-phase chromatography, such as detrimental interaction with column silanol groups, and overloading which both lead to poor peak shapes. Method... Read More about The challenges of the analysis of basic compounds by high performance liquid chromatography: Some possible approaches for improved separations.