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.
This is the third “LC Troubleshooting” column in a series related to problems that we associate with liquid chromatography (LC) columns. This month is the first of several discussions looking at problems that are caused by chemical problems with the column.
The silica-based packing in reversed-phase columns is not inert. Here we consider what happens when the mobile-phase pH is too high or too low.
Strongly retained sample compounds can cause various changes in the appearance of a chromatogram.
Particulate matter from the sample or the system can cause havoc in the chromatogram.
Particulate matter from the sample or the system can cause havoc in the chromatogram.
How to get started in the process of identifying the problem source for column-related problems.
How to get started in the process of identifying the problem source for column-related problems.How to get started in the process of identifying the problem source for column-related problems.
Are your solvent costs too high? Here are some ideas on how to decrease the amount of mobile phase you use.
Solvent costs too high? Here are some ideas on how to decrease the amount of mobile phase you use.
Are your solvent costs too high? Here are some ideas about how to decrease the amount of mobile phase you use.
Are your solvent costs too high? Here are some ideas about how to decrease the amount of mobile phase you use.
I recently returned from a tour of teaching liquid chromatography (LC) classes to users in Minnesota, the United Kingdom, Poland, and Malta. One thing that always impresses me on such trips is that no one group has a corner on the LC problem market. The same problems pop up in most laboratories, no matter where they are located, the role of the laboratory (for example, analytical, forensic, production, research), what industry is involved, or the brands of instrumentation used.
No matter where you live or who you work for, you’re likely to encounter one or more of these liquid chromatography (LC) column problems at some point.
No matter where you live or who you work for, you’re likely to encounter one or more of these liquid chromatography (LC) column problems at some point.
How to distinguish between LC column overload and detector overload.
How to distinguish between liquid chromatography (LC) column overload and detector overload.
The potential causes are considered for peak distortion for the first two peaks in the chromatogram.The potential causes are considered for peak distortion for the first two peaks in the chromatogram.
What are possible causes for distortion of the first two peaks in a chromatogram?
Unexpected results from calibration standards create confusion in a clinical liquid chromatography (LC) method.
Readers’ questions regarding problems related to internal standard calibration of liquid chromatography methods are addressed.
Readers' questions regarding problems related to internal standard calibration of liquid chromatography methods are addressed.
Unexpected results from calibration standards create confusion in a clinical liquid chromatography (LC) method.
Recently, I received an inquiry from a reader regarding a problem he encountered with a routine liquid chromatography (LC) method in his clinical laboratory.
When converting methods from liquid chromatography (LC) to ultrahigh-pressure liquid chromatography (UHPLC), don't get confused by flow-rate settings.
When converting methods from LC to UHPLC, don’t get confused by flow-rate settings.
A stepwise process is described to help isolate and identify the cause of a method failure.
One of the most frequent times that we discover a problem with a liquid chromatography (LC) method is when we examine a data set following the analysis of a batch of samples.
A stepwise process is described to help isolate and identify the cause of a method failure.
Why are liquid chromatography retention times sometimes so slow to stabilize?
Why are LC retention times sometimes so slow to stabilize?
