Size exclusion chromatography and MALDI-TOF mass spectrometry can be effectively coupled via a robotic interface, where chromatographic fractions are sprayed directly onto a moving MALDI-TOF target through a heated capillary nozzle. The target is precoated with an appropriate matrix, such as dithranol. For polydisperse synthetic polymers a continuous track of matter is deposited onto the matrix surface. After deposition of the sample fractions, the MALDI-TOF target is introduced into the spectrometer, and spectra are taken from different positions of the polymer track. As a result, well-resolved spectra are obtained which are characteristic for different molar mass fractions of the sample. In the case of copolymers, information on molar mass and copolymer composition is accessible. (C) 2000 Elsevier Science Ltd. All rights reserved.