HPLC analysis of aliphatic sulfonate surfactants using ion-pair detection.
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A method was developed for the analysis of a number of surfactants which contained no UV-chromophores, using RP-HPLC with Indirect Photometric Detection, IPD. Pyridinium salts such as N-methylpyridinium iodide, N-methyl-2,2'-dipyridinium iodide and N,N'-dimethyl-2,2'-dipyridinium diiodide, were used as the visualization reagents, forming ion-pair complexes with the sulfonate surfactants. This allowed ordinary UV-detection. N-methylpyridinium iodide proved to be a suitable reagent, both with respect to ease of preparation and response. The eluents consisted of mixtures of acetonitrile and water, being 0.1 - 0.25 mM with respect to pyridinium salt. The method was sensitive and exhibited good signal to noise ratios, as well as linear responses over a wide concentration range. All of the analyzed surfactants were separated, including the diastereomeric forms of some of the surfactants. (+info)
Identification of Campylobacter jejuni genes contributing to acid adaptation by transcriptional profiling and genome-wide mutagenesis.
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A comparative electron paramagnetic resonance study of the nucleotide-binding domains' catalytic cycle in the assembled maltose ATP-binding cassette importer.
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Activation of mouse and human peroxisome proliferator-activated receptor alpha by perfluoroalkyl acids of different functional groups and chain lengths.
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