Liquid Chromatography (LC/HPLC)

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Since September 2008, 294 000 infants and young children suffered urinary problems as a result of the contamination of melamine in infant milk powder and were hospitalized. This hospitalization was required to treat the symptoms caused by the ingestion of melamine contaminated infant formula and related dairy products. Previously in 2007, pet food, animal feed wheat gluten and other protein-based foods were found to contain residues of melamine and its degradation product cyanuric acid.

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Hydrophilic interaction liquid chromatography (HILIC) offers unique advantages for the separation of very polar compounds when compared to reversed-phase chromatography. A new silica based HILIC phase was developed to provide additional selectivity options in HILIC separations. The separation of water soluble vitamins on the new TSKgel NH2-100 HILIC column and on the well known TSKgel Amide-80 HILIC column demonstrates the differences in selectivity.

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Forensic laboratories face a daunting task to identify trace amounts of controlled substances in small samples of seized evidence. Unambiguous identification is required to meet the stiff challenge that is sure to be raised in the courtroom. Positive proof is especially difficult to establish if the controlled substance is hidden in a complex food matrix with a high content of sugars, fats, fatty acids, proteins and alkaloids.

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Penicillins are regulated substances in food for human consumption. The minimum residue limits range from 1 ng/g to as high as 50 ng/g depending on the compound. Because of the complexity of food matrices measuring the level of contaminants requires a total solution composed of sample extraction, sample clean-up, chromatographic separation and detection. In this paper, a solid-phase extraction method with a high performance liquid chromatography tandem mass spectrometry method (HPLC–MS–MS) is shown for the simultaneous determination of six antibiotic residues.

Waters Corporation (Milford, Massachusetts) has acquired Thar Instruments (Pittsburgh, Pennsylvania), a supercritical fluid chromatography (SFC) manufacturer.

Researchers from Queen's University (Kingston, Ontario, Canada) developed porous polymer capillary columns with varied flurous content for chromatography of tagged analytes.

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.

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Using a fixed length-variant of the kinetic plot method, it is illustrated how an analysis that is performed near the optimal flow-rate of a given commercial column can, in many cases, be performed between 50–200% faster by switching to a longer column and operating it at a higher pressure - at least, if the available instrument pressure admits so. The present article aims to show that short columns are not always the best choice to get the fastest separation.

Italian researchers in Rome (Universita Cattolica and Consiglio Nazionale delle Ricerche) and Cagliari (Universita di Cagliari) have used reversed-phase high performance liquid chromatography with electrospray ionization mass spectrometry to analyze naturally occurring salivary peptides from subjects with autism and compare the profiles with those obtained from age-matched control subjects.

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.

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An ultrafast gradient LC separation method was developed to separate a 5-component drug mixture in 30 seconds, with peak widths of 1 second. maXis mass accuracy at sub-ppm levels and true isotopic pattern of the spectra from the peaks lead to a confident elemental formula assignment for each drug compound with the SmartFormula algorithm.