May 1, 2008
By:
John W. Dolan
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Getting started on the right foot is important for efficient method development.
Different methods require different strategies.
Feb 1, 2008
By:
John W. Dolan
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Different methods require different strategies.
Why aren't retention times constant?
Dec 1, 2007
By:
John W. Dolan
|
The various surface characteristics have different capacities and equilibration rates, which can affect the appearance of the chromatograms.
How can you reduce mobile phase expenses?
Sep 1, 2007
By:
John W. Dolan
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How can you reduce mobile phase expenses?
Jul 1, 2007
By:
Mark Sinnott, Simon Jones, Allen Vickers
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Modern gas chromatography (GC) capillary columns are rugged and forgiving but some care should be taken when handling and using these high-efficiency columns. In this instalment of "Column Watch", the authors discuss the issues surrounding avoiding column breakage, stationary phase damage and column contamination. Prolonging the life of a column by keeping an oxygen-free system, providing a cleaner sample and not exceeding the upper temperature limit of the stationary phase are highlighted in this practical discussion.
Excess variability is not acceptable in a pharmaceutical method.
Jun 1, 2007
By:
Nastaran Sigari, John W. Dolan
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Mass overload is related to the mass of sample that can be injected before the stationary phase is sufficiently loaded to cause changes in the chromatography.
Chromatographers worldwide suffer from the same problems.
Mar 1, 2007
By:
John W. Dolan
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As I write this instalment of "LC Troubleshooting", I have just completed teaching a series of liquid chromatography (LC) method development classes to pharmaceutical scientists in India. As a parting gift, my host gave me a copy of Thomas Friedman's The World is Flat?.1 One central theme of this book is that the technology and skills for the science and information technology sectors are available around the world and are no longer the exclusive domain of the US and Western Europe.
Proper 'data handling' means that the data to be treated should be acquired in a suitable way. The use of experimental designs makes it possible to define a priori the experiments to be executed and the data to be collected. Data handling of the results obtained should lead to method conditions satisfying the need(s) of the separation considered. This article describes the experimental design-based approaches applied in the development and optimization of separation methods.
Sep 1, 2006
By:
Yvan Vander Heyden
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An experimental design can be considered as a series of experiments that, in general, are defined a priori and allow the influence of a predefined number of factors in a predefined number of experiments to be evaluated.
