A generalised method for the deconvolution of mass spectral data from the aerodyne aerosol mass spectrometer (AMS) is presented. In this instrument, the sampled ensemble of gas and non-refractory particle phase materials interfere with each other in the mass spectra and the data must be systematically analyzed to generate meaningful, quantitative and chemically resolved results. The method presented here is designed to arithmetically separate the raw data into partial mass spectra for distinct chemical species. This technique was developed as part of the AMS analysis tools introduced by Allan et al. (J. Geophys. Res. Atmos. 108 (2003) 4090) and is in use by most groups within the AMS users community. This technique employs a user-definable ‘fragmentation table’ for each chemical species or group of species, and examples of some tables designed for the interpretation of field data are given. The ongoing work being performed to develop and validate the tables will be presented in future publications.