Also in splitless injection, the sample must be vaporized above the column entrance. Splitless injection was conceived for sample evaporation in the gas phase between the needle exit and the column entrance, which, as we know today, presupposes nebulization at the needle exit. Evaporation in the gas phase largely avoids adsorption on surfaces and, hence, allows even high-boiling and other difficult compounds to reach the column unhindered. So far, my father s rule is accurate. Fast autosamplers do not reproduce the conditions of manual injection for which the empty liner was designed.
Injection is performed in such a short time that evaporation inside the syringe is avoided.
Solute degradation on the metal surfaces at the bottom of the injector results not from the chemical activity of these surfaces, but from how the sample material gets there. One of the samples analyzed is injected a second time by the on-column technique. If no on-column injector is available on the instrument, the column is dismantled from the vaporizing injector. Use either an on-column syringe with a thin needle or a short piece of 0.53mm i.d. precolumn to enable injection with a standard syringe. Conditions ensuring nebulization You may want to test whether conditions for nebulizing the sample would improve your results.