The analytical high-speed countercurrent chromatograph (HSCCC-4000) previously reported has been successfully interfaced to a JEOL mass spectrometer using a frit method. The frit interface requires a low pressure (2Kg/cm(2)) and eliminates various complications caused by a thermospray method which would produce a high back pressure of 2OKg/cm(2). In addition, the method can be applied to analytes with a broad range of polarity by choosing Frit/EI, Frit/CI or Frit/FAB. A series of preliminary studies shows that the best partition efficiency can be obtained from multilayer coils of 0.3 to 0.5mm ID PTFE (polytetrafluoroethylene) tubing with a total capacity of several milliliters. The HSCCC-4000 produces the efficient separations at a flow rate between 0.1 and 0.2ml/min whereas the optimum feed rate for the Frit/MS ranges between 1 and 5(mu)l/min. Therefore, the effluent from the HSCCC column was introduced into the Frit/MS after passing through an adjustable split tee which splits the stream at a desired ratio of 1:40 by applying a 2m length of O.1mm ID tubing at the exhaust line. The performance of the apparatus was demonstrated in three sets of model experiments: 1) Separation of indole auxins with a solvent system composed of hexane/ethyl acetate /methanol/water (1:1:1:1, v/v/v/v) under Frit/EIMS conditions: 2) Analysis of mycinamicins with hexane/ethyl acetate/methanol/water (1:1:1:1,v/v/v/v) under Frit/CIMS conditions: 3) Analysis of colistin complex with n-butanol/0.04M TFA (1:1,v/v) containing 1% glycerol under Frit/FABMS conditions.