Plasma proteins electrophoretic measurements

Multi-variable or cold-ethanol precipitation techniques yielded plasma protein fractions rich in lipoprotein (Oncley et al. 1949). These isolation procedures were extremely important. They demonstrated that physical properties such as solubility could be studied with lipoproteins as well as other proteins. Electrophoretic mobilities and specific refractive increments of lipoproteins were shown to be measurable properties (Armstrong et al. 1947 a and 1947 b). A detailed analysis of lipoprotein composition was undertaken (Oncley et al. 1950). 

In a similar effort to combine preconcentration with electrophoretic separations, Fortier et al. [123] investigated the analytical performances of a microfluidic system comprised of an enrichment column, a reversed phase separation channel, and a nanoelectrospray emitter embedded together in polyimide layers. The authors demonstrated that the configuration minimized transfer lines and connections and reduced peak broadening and dead volumes, resulting in good reproducibility of retention time and peak intensity. The microchip was interfaced to both ion trap and TOF MS. Measurements were performed for a dilution series of protein digests spiked into rat plasma samples and provided an LOD of 1-5 fmol. 

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