Influence of injection parameters on column performance in nanoscale high-performance liquid chromatography

The influence of the injection volume and the sample solvent on column effi ciency has been evaluated in packed nano liquid chromatography using column s 150 mu m i. d. Evaluation of column performance was by means of reduced p late height (h) versus reduced velocity (v) for four polyaromatic hydrocarb on test compounds (PAHs). When compounds are dissolved in a weak solvent (s uch as MeCN: H2O, 30:70), and whatever the injection volume - 60 or 200 nL - again in efficiency can be observed due to the well-known on-column focus ing phenomenon, but keeping constant solute retention factors. Under optimi zed conditions (flow rate: 150 nL min(-1), solvent sample MeCN: H2O, 30:70, injection volume 200 nL), a reduced plate height of 1.83 has been obtained for a 15 mu m C-18 packing corresponding to 36000 plates m(-1), which illu strates the absence of any extra-column band broadening under nano LC condi tions.