An on-line solvent (eluent) evaporator is used for reconcentrating a fraction from a first LC column before introduction into a second LC separation step, possibly involving another mobile phase. For pentane and pentane containing 10% of dichloromethane, evaporation rates of 1 ml/min were achieved, On evaporating a volume of 6 ml, 2-ethylnaphthalene was retained to more than 75%, Separation of aliphatic and polyaromatic hydrocarbons in a linseed oil is shown as an application.
