 | Sep 1, 2006
By:Ronald E. Majors
Traditional methods for the sample preparation of insoluble solid materials have represented one of the more time consuming and labor intensive efforts in analysis. In this installment of "Sample Prep Perspectives," Ron Majors examines modern sample preparation methods for solids that often involve increased temperature and higher pressure to speed up the extraction process. In addition, modern sample preparation methods have been automated to relieve analysts of the drudgery associated with traditional methods. Here, he reports on automated Soxhlet extraction, supercritical fluid extraction, pressurized fluid extraction–accelerated solvent extraction, and microwave-assisted extraction and updates earlier coverage.
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 | Sep 1, 2006
By:John W. Dolan
There always seems to be one more way an LC system can fail.
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 | Sep 1, 2006
By:Donald S. Risley, Brian W. Pack
The objective of this work was to develop a universal high performance liquid chromatography method that is capable of simultaneously retaining and separating both cations and anions within a single chromatographic analysis for the purpose of quantification in pharmaceutical products. A zwitterionic stationary phase operated in the hydrophilic interaction chromatography (HILIC) mode in conjunction with evaporative light scattering detection was investigated for the separation and quantitation of 33 commonly used pharmaceutical counter ions, 12 cations, and 21 anions. Using a single gradient chromatographic analysis, both anions and cations were easily separated from each other in addition the parent pharmaceutical molecules also were separated.
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 | Sep 1, 2006
By:John V. Hinshaw
Gas chromatographs contain a large number and variety of fittings, ferrules, tubing, and connections, all of which must be properly assembled, tightened, and leak-free if the system is to perform at its best. This month, John Hinshaw discusses how to make, maintain, and troubleshoot various types of connections used in gas chromatographs.
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 | Jun 1, 2006
By:Joseph J. Pesek, Maria T. Matyska
Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples with a broad range of chemical properties.
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 | Jun 1, 2006
By:John V. Hinshaw
John Hinshaw takes a look at how choosing a suitable syringe for a specific application can be difficult, especially if the inlet system has special requirements; choosing the wrong syringe can cause significant problems.
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 | Jun 1, 2006
By:Robert L. Grob, Mary A. Kaiser
The Stephen Dal Nogare award is one of the oldest and most prestigious awards given in chromatography. Little has been written about Stephen Dal Nogare "the man" or his contributions to scientific knowledge, including his unique contributions to separations science. This article describes his scientific career and how it has influenced the practice of chromatography.
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 | Jun 1, 2006
By:Ronald E. Majors
Liquid-liquid extraction (LLE) is among the most widely used sample preparation methods. In this month's installment of "Sample Prep Perspectives," Ron Majors discusses newer LLE approaches that offer significant advantages over classical methods.
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 | Jun 1, 2006
By:John W. Dolan
John Dolan delves deeper into dwell volume, a subject that was touched upon in a recent installment of "LC Troubleshooting."
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