A novel probe is described that is capable of sampling liquid from droplets dispersed in a gas in such a way that the composition of the liquid is not changed during the sampling process. A unique feature of the probe design is the use of a wick of fibers that allows liquid to pass into the probe but excludes vapor. Another important feature is an ability to vary the flux of liquid droplets to the probe inlet over a substantial range. Such variation allows one to choose an operating condition that ensures the absence of composition distortion during the sampling process. The effectivness of the probe is demonstrated by experimental results obtained with dispersions of charged droplets now in common use as sources of ions in electrospray ionization mass spectrometry.