Liquid Chromatography

The second part of this series focuses on the allowable adjustment in the ratio of aqueous (A) to organic (B) components of a reversed-phase mobile phase.

In the first part of this series, an overview of the concept of method adjustment vs method change in reversed-phase HPLC is presented.

PEEK (poly-ether-ether-ketone) fittings and tubing are in widespread use for HPLC applications. The convenience of using your fingers instead of a wrench to tighten the fittings and the flexibility of the tubing make PEEK the material of choice for...

As part of the HPLC Master Classes that I teach, I start each class by gathering questions or topics that the attendees would like to know more about. In a recent class in London, one of the topics was the causes of excessive retention – a method in...

This technical article takes a closer look at the influence of temperature on the separation.

In the previous three instalments of this series ('#7: Fundamental Resolution Equation, Part 1', '#8: Fundamental Resolution Equation, N', '#9: Fundamental Resolution Equation – Alpha'), we’ve looked at the fundamental resolution equation

In the previous two articles ('#7 Fundamental Resolution Equation, Part 1' and '#8 Fundamental Resolution Equation, N'), we’ve looked at the fundamental resolution equation

In the previous article we began our study of the fundamental resolution equation

In our last Back-to-Basics discussion (#6 Resolution), we looked at the way we measure resolution, R_s, from a chromatogram using the following equation:

This technical article introduces the solvent-strength nomogram, a tool to pick the (approximately) equal strength of one solvent from another.

If you use gradient elution for your HPLC separations, sooner or later you will run into problems with peaks that appear in the blank. Variously described as ghost peaks, background peaks or gradient interferences, these peaks can drive you crazy,...

JASIS is one of the largest exhibitions in Asia for analytical and scientific instruments. JASIS stands for "Japan Analytical & Scientific Instruments Show" and is the cutting-edge scientific instruments, analytical system & solution exhibition...

This article discusses pipette calibration that shouldn't be ignored as it may be the key for consistent results.

Q: I have a problem with the linearity of my HPLC method. The method involves derivatization of the analyte, followed by reversed-phase separation with UV detection. To my surprise, the calibration curve fits a quadratic form very nicely, and not a...

Q: I’m hoping you might be able to shed some light on an issue we’ve had with unknown peaks in nearly every method we run in our lab. I’ve been working at µg/mL levels for a cleaning method for one product, while a colleague has been working at...