Liquid Chromatography (LC/HPLC)

Understanding the interactions that stationary-phase chemistries provide will help you choose the most appropriate blend of interactions to address a given separation challenge.

Methotrexate and sulfasalazine are often used together to treat rheumatoid arthritis, so it is valuable to be able to monitor plasma levels of both drugs simultaneously. This method achieves that by using two detector wavelengths, 304 nm for methotrexate and 358 nm for sulfasalazine.

Have a problem with your LC system? Maybe applying a little "DDT (Don't Do That)" may help.

Applications of miniaturized separation techniques for the analysis of illicit drugs and new psychoactive

This review will provide a brief introduction to active flow technology (AFT) with a particular focus on improvements in separation performance that can be achieved when using these columns and coupling with liquid chromatography–mass spectrometry (LC–MS).

The ideal UV detector would allow us to monitor the presence of our target analytes without influence from the background eluent and sample matrix components that may be present in the detector measuring cell at the same time

Environmental sample analysis by large-volume injection (LVI) in combination with liquid chromatography–tandem mass spectrometry (LC–MS-MS) is described for polar and nonpolar analytes in both aqueous samples and organic extracts.

Make your column last forever? Not quite, but you can help prevent its early demise. 

This review illustrates the benefits of LC?C in food analysis and discusses the combination of LC modes used in the two dimensions, and the nature of the samples analyzed.

A simple and rapid method for the simultaneous separation and determination of the inorganic ionic forms of As(III), As(V), Sb(III), Sb(V), Tl(I), and Tl(III) in river water samples is described.

Supercritical (subcritical) fluid chromatography (SFC) was evaluated as an alternative to HPLC for the enantiomeric separation of primary amines on a cyclofructan-based chiral stationary phase.

A discussion of the role of the gradient in separation by reversed-phase and ion-exchange HPLC, with data from two products to illustrate the key points

Understanding the chemistry of embedded polar group and perfluorophenyl phases leads to better decisions during method developement

How can resolution be determined when peak width cannot be measured?

Mechanical strength, acid and alkaline durability, loadability, and overload characteristics are a few of the parameters evaluated.

When transferring a method between HPLC and UHPLC, various potential pitfalls may result in selectivity differences, changes in efficiency, and failure to meet resolution system suitability criteria.

Because of improved technologies and other changes in modern HPLC, these seven common practices are now highly questionable.

Small changes in retention time with an LC method are normal. At what point is a problem suggested?

Ion chromatography (IC) is often used for the chromatographic separation of a wide range of compounds. In a laboratory that already uses HPLC or UHPLC, will the implementation of IC be expensive in terms of instrumentation or resources?The Column spoke to Ade Kujore of Cecil Instruments Limited to find out.

The first commercial capillary ion chromatography (IC) systems became available in 2010, but uptake of the technique has been slow even though it has many benefits. Here, we review those benefits and present selected application areas where it is proving especially useful.

Why should you be concerned about mobile-phase degassing?

Highlights of the discussions on column-technology topics - such as monoliths, high-pH columns, SPPs, and HILIC - and an analysis of the larger trends observed at the conference.

To solve problems with UV detectors, it helps to understand a few things about how the detector cells are designed.

A series of real life problems submitted by ChromAcademy members

Developments in the preparation of organic polymer monoliths suitable for the separation of small molecules in the isocratic mode are described and the main factors affecting column efficiency are identified.

An updated overview of the development of SPP technology, including benefits, limitations, and the theory behind its success

An interview with Jack Kirkland on his pioneering career in HPLC

A look at two reader-submitted questions regarding method calibration

Chromatographers are faced with a plethora of analytes, contained within a variety of matrices, for testing. The process of developing different methods can be a tricky, time-consuming process. Ade Kujore from Cecil Instruments Limited, Cambridge, UK, summarizes many of the issues that should be addressed throughout the method development process.

Some attributes of large molecules make them behave differently from small molecules in reversed-phase separations.