John W. Dolan

John Dolan has been writing "LC Troubleshooting" for LCGC for over 25 years. One of the industry's most respected professionals, John is currently a principal instructor for LC Resources, Walnut Creek, California He is also a member of LCGC's editorial advisory board.

Sometimes when changes are made to gradient conditions, the result isn't what was expected.

Is it possible to get the same separation under isocratic and gradient conditions?

In contrast to isocratic separations, gradient elution can sometimes seem to be counter-intuitive. Yet with the proper perspective, the things we intuitively understand about isocratic methods apply in a similar manner to gradients.

It is important to consider the influence of the sample matrix when setting up an analytical method

How to account for the sample matrix when developing a method

How to choose conditions and what to do with the results

The use of a gradient scouting run can be a powerful tool to jump-start method developent. But what conditions should be chosen, and what do we do with the results?

A description of how refractive index detectors work and some good practices to get the most out of this powerful detector

The refractive index detector can be frustrating to use because of its extreme sensitivity to temperature and other variables. However, it can see things that no other detector can see.