HPLC

A change in the mobile phase strength can be a powerful tool to move peaks in a separation.

This article describes the operating principles of the direct-electron ionization (EI) interface, which is becoming more popular in many LC–MS applications. Matrix effects and the role of direct-EI as a universal detector for small molecule analysis are also discussed in detail. The advantages and drawbacks of this approach are described and a comparison with atmospheric pressure ionization (API) interfaces is made. The potential of direct-EI is illustrated with a selection of practical applications.

The authors discuss an LC method for the direct analysis of diquat and paraquat in lake water.

A change in the mobile phase strength can be a powerful tool to move peaks in a separation.

Examining the properties of the three most commonly used solvents and how to select the most suitable mobile phase composition.

John Dolan presents some practical pointers to get the most out of your UHPLC system.

This article highlights a number of recent developments in HPLC for polyphenol analysis.

The guest authors describe an optimization procedure to achieve the highest plate count in a given analysis time.

Industry veteran Thomas Beesley takes readers on a tour of his experiences in chromatography.

An essential guide to getting the most from your UHPLC system.

John Dolan discusses an inquiry he received from a reader complaining about the difficulty he was having meeting system suitability for an LC method that had been transferred into his lab.

If something doesn't look right you need to investigate!

The principles and attributes of today's HPLC detectors are discussed, and the advantages and disadvantages of the various detectors are compared and contrasted.

How to make gradient separations faster without changing the separation

Guest author Stefan Brand and John Dolan take a look at how to speed up gradient separations while avoiding common errors.

The authors compare five bonded phases with bare silica for the SFC separation of a 19-component mixture of polar analytes.

Ron Majors presents his yearly review of the HPLC Conference.

The authors describe a study of screening procedures that demonstrated a relatively small set of columns can be used routinely.

Deterioration of the separation can result from many causes. This month's column looks at some techniques to isolate the problem source.

The author examines the process of validating a CDS and describes the trials along the way such as speed of validation, risk management, and so forth.

Well-known industry veteran and LCGC EAB member Peter Carr looks back at the early days of the chromatography field and reflects on his own experiences.

John Dolan looks at a case in which the peak doesn't seem to belong with the neighboring peaks in the chromatogram.

The basics of IC are reviewed and recent advances that may extend this technology to new applications are discussed.

The coauthors discuss the various attributes of and approaches to reversed-phase chromatography.

John Dolan reaches a milestone with his 300th installment of "LC Troubleshooting" and takes a look back through the years.