John W. Dolan

John Dolan has been writing "LC Troubleshooting" for LCGC for over 20 years. One of the industry's most respected professionals, John is currently the Vice President of BASi Northwest Laboratory, McMinnville, Oregon and a principal instructor for LC Resources, Walnut Creek, California. He is also a member of LCGC's editorial advisory board.

Part IV of this series focuses on three different calibration models: external standardization, internal standardization, and the method of standard additions.

This is the third installment in a series of LC Troubleshooting columns that focus on calibration curves used for LC methods. Here, John Dolan considers some alternate ways to look at the data to determine if they appear to be normal or are trying to tell us something is amiss.

In part two of this series, John Dolan looks at the signal-to-noise ratio and its relationship to uncertainty in a measurement.

This month's "LC Troubleshooting" looks at some different calibration models, how to decide if a calibration curve goes through zero, and some problems that can occur if the wrong choices are made.

This month's "LC Troubleshooting" discussion will center on the recommendations of the CDER document, especially in terms of what it means from a practical method performance standpoint.

At the beginning of the year, it is good to look back in time- are there things that we can learn from the past? After a series of troubleshooting and method development seminars in Istanbul, Turkey, and Amman, Jordan, John Dolan looks back.

This month's "LC Troubleshooting" installment will take a look at the design of these durable pumps and also examine some of the potential weaknesses and how to overcome them.

All the buzz lately about LC columns packed with particles smaller than 3 mm often comes with warnings about extracolumn effects. This month's installment will take a look at what these effects are and more.

This "LC Troubleshooting" installment marks the beginning of the 26th year that John Dolan has written this column.