Suoraan toisiinsa liitetyt nes-tekromatografiakolonnit soveltuvat erinomaisesti pienten ainemäärien analysointiin hankalista matriiseista. Menetelmä mahdollistaa automatiikan käytön, jolloin säästytään työläiltä näytteen käsittelyvaiheiIta. Onkin sanottu, että ainoa rajoitus menetelmän hyödyntämisessä on analyyttisten kemistien luovuuden puute.%Column switching and multidimensional chromatography involve the cleanup or separation of multicomponent mixtures by online selective transfer of a fraction or fractions from one chromatographic column to one or more secondary columns, for the purpose of additional separation. On-line multidimensional chromatography allows complex samples to be broken into manageable portions, resulting in improved speed, precision, and chromatographic resolution. Food and beverages and environmental samples can be analysed, and biological fluids such as serum and urine investigated for drugs, with minimal sample preparation. In general, these sample matrices are too complex to be handled by single-column HPLC separation. Trace enrichment, a special adaptation of the technique, is often used in the analysis of water or biological fluids for trace organics. A large volume of water is passed through a highly retentive precolumn placed in the sample-loop position of a liquid sampling valve, and the organics retained by the precolumn are then eluted into the HPLC analytical column. Two applications are considered: the determination of E-2-nonenal in beer at ultra trace level and a screening method for in-time monitoring of organic impurities in river water.
展开▼
