Peak compression in CEC is a phenomenon that can generate very narrow peaks with extremely high efficiencies that defy current chromatographic theory. This review article summarises the content of publications in this area up to this date. Two main types of peak compression effects have been observed in the literature.
View Article and Find Full Text PDFThe peak compression effect has been applied to improve quantification limits in chiral capillary electrochromatography (CEC). A stationary phase based on the chiral selector vancomycin (Chirobiotic V) was used for separations of the enantiomers of mianserin. By adding solvents with a low dielectric constant, e.
View Article and Find Full Text PDFThe complementary use of gas chromatography-mass spectrometry (GC-MS), gas chromatography-atomic emission detection (GC-AED) and nuclear magnetic resonance (NMR) spectroscopy is demonstrated by the identification of four major by-products in a sample from an exploratory attempt to synthesise 1.3-dichloro-5-(difluoromethoxy)benzene. GC-MS was used for straightforward identification of the target compound and one of the impurities.
View Article and Find Full Text PDFTwo different automated generic liquid chromatography screens for the separation of chiral compounds of pharmaceutical interest have been evaluated. The test set comprised 53 chemically diverse chiral compounds involving 55 enantiomeric pairs from the pharmaceutical industry (i.e.
View Article and Find Full Text PDFAn example of the complementary use of GC-MS. GC-AED and GC-FT-IR is described for efficient structure elucidation of an unknown impurity in pharmaceutical analysis. None of the analytical techniques could solve the structure of the unknown impurity alone; identification was, however, straightforward by combining the available spectroscopic information.
View Article and Find Full Text PDFPeak compression effects in capillary electrochromatography of basic drug substances using a strong cation-exchanger have been studied. Extremely narrow peaks with apparent efficiencies of several million plates per meter could be obtained when the composition of the sample zone differed from that of the mobile phase. The increased efficiencies were predominately observed when the analyte had an elution time similar to that of the electroosmotic flow marker.
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