(167b) Isotachophoresis: from Grams to Nanograms

One of the grand challenges posed by the human proteome is the quantification of low-abundance proteins which may represent less than a billionth of the total protein mass in a sample. Isotachophoresis has a number of unique properties which make it an excellent candidate for use as a first dimension of separation in a multi-dimensional separations platform. First, it is largely independent of scale and can handle mass loadings from grams down to picograms. Second, it can concentrate dilute target solutes by orders of magnitude while removing contaminants and forming zones of pure proteins. Third, ITP is self-sharpening and so it can recover from dispersion, e.g., induced by migration around a bend. Fourth, it can be carried out at virtually any pH and ionic strength for which leading and terminating electrolytes are available, thus avoiding the issue of isoelectric precipitation. Finally, a train of purified ITP zones can be made to halt at a predictable point in a channel, allowing components to be added or subtracted from the stack. This talk will use both models and experiments to demonstrate each of these features and then conclude by showing how ITP might be used in a multi-dimensional separations platform.