Solvent trapping during large volume injection with an early vapor exit part - Part 3: The main cause of volatile component loss during partially concurrent evaporation

When 0.53 mm i.d. uncoated precolumns connected to a solvent vapor exit are used for sample introduction with partially concurrent solvent evaporation , substantial losses of volatile solutes are often observed. They were foun d to be the consequence of solute accumulation at the front end of the floo ded zone, which in turn is the result of a strong pressure drop over the fl ooded zone owing to the formation of plugs of sample liquid, The pressure d rop causes significant solvent evaporation at the front, which enriches the solute material there and causes its loss. The use of 0.32 mm i.d. restric tions between the uncoated precolumn and the vapor exit greatly reduced thi s problem.