All Outputs (57)

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 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.

Shell particle and UHPLC technologies for fast analysis of polar compounds in the HILIC mode (2012)
Book Chapter

Contributions to reversed-phase column selectivity. II. Cation exchange (2011)
Journal Article

The contribution of cation exchange to solute retention for type-B alkylsilica columns (made from high-purity silica) has been examined in terms of the hydrophobic-subtraction (H-S) model of reversed-phase column selectivity. The relative importance... Read More about Contributions to reversed-phase column selectivity. II. Cation exchange.

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.

Performance of silica monoliths for basic compounds. Silanol activity (2011)
Book Chapter

The large majority of pharmaceuticals, and in addition many compounds of biomedical significance, contain ionisable basic groups. This chapter considers the analysis of these important compounds on silica monolith columns.

A systematic investigation of the effect of sample diluent on peak shape in hydrophilic interaction liquid chromatography (2010)
Journal Article

The aim of this study was to evaluate the importance of sample diluents to improve peak shapes in hydrophilic interaction liquid chromatography (HILIC), using low molecular weight (

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.

Further investigations of the effect of pressure on retention in ultra-high-pressure liquid chromatography (2010)
Journal Article

In this study, we investigated further the large increases in retention with pressure that we observed previously in RP-LC especially for ionised solutes. These findings were initially confirmed on a conventional silica C18 column, which gave extreme... Read More about Further investigations of the effect of pressure on retention in ultra-high-pressure liquid chromatography.

How to obtain good peak shapes and efficiences in liquid chromatography in reversed-phase and hydrophilic interaction separations (2009)
Presentation / Conference Contribution

Practical assessment of frictional heating effects and thermostat design on the performance of conventional (3 μm and 5 μm) columns in reversed-phase high-performance liquid chromatography (2009)
Journal Article

A practical investigation of frictional heating effects in conventional C18 columns was undertaken, to investigate whether problems found for sub-2 μm columns were also present for those of particle size 3 μm and 5 μm and different internal diameter.... Read More about Practical assessment of frictional heating effects and thermostat design on the performance of conventional (3 μm and 5 μm) columns in reversed-phase high-performance liquid chromatography.

Some new advantages of HILIC over RP-LC for the separation of drugs and other ionisable compounds (2009)
Presentation / Conference Contribution

A new approach to the determination of column overload characteristics in reversed-phase liquid chromatography (2009)
Journal Article

Column overloading is very common during the separations of basic analytes in analytical scale reversed-phase liquid chromatography (RPLC). Due to the complex interactions of ionic analytes with stationary and mobile phases, only a very small amount... Read More about A new approach to the determination of column overload characteristics in reversed-phase liquid chromatography.

Problems in the analysis of pharmaceuticals and other basic solutes in HPLC: Some solutions using recently developed columns (2008)
Presentation / Conference Contribution

Investigation of the effect of pressure on retention of small molecules using reversed-phase ultra-high-pressure liquid chromatography (2008)
Journal Article

The effect of inlet pressure on the retention of a series of low molecular weight acids, bases and neutrals, was investigated at constant temperature in reversed-phase liquid chromatography using a commercial ultra-high-pressure system (Waters UPLC i... Read More about Investigation of the effect of pressure on retention of small molecules using reversed-phase ultra-high-pressure liquid chromatography.