Short polystyrene monolith-fritted micro-liquid chromatography columns for rapid isocratic analysis of pharmaceuticals direct from plasma

The manufacture of micro-HPLC columns with combined stationary phases, a body of 3.5-mu m XTerra-C-18 particles, and poly(styrene-divinylbenzene) (PS-DVB) frits is described in detail. The efficiency of the columns was assessed by rapid separation of neutral and acid compound mixtures. Direct analysis of some pharmaceuticals in plasma resulted in lower limits of detection (LOD) for salmeterol xinofate of 12.5 nanograms on-column.