The invention relates to a mass spectrometry method for analysing mixtures of substances using a triple quadrupole mass spectrometer, whereby said mixtures of substances are ionised prior to analysis. The invention is characterised in that the method comprises the following steps: a) selection of a mass/charge quotient (m/z) of an ion created by ionisation in a first analytical quadrupole (I) of the mass spectrometer; b) fragmentation of the ion selected in step (a) by applying an acceleration voltage in an additional subsequent quadrupole (II), which is filled with a collision gas and acts as a collision chamber; c) selection of a mass/charge quotient of an ion created by the fragmentation process in step (b) in an additional subsequent quadrupole (III), whereby steps (a) to (c) of the method are carried out at least once; and d) analysis of the mass/charge quotients of all the ions present in the mixture of substances as a result of the ionisation process, whereby the quadrupole (II) is filled with collision gas, but no acceleration voltage is applied during the analysis. Steps (a) to (c) and step (d) can also be carried out in reverse order.