The quality of drinking water is an important issue nowadays. Due to the fast spreading of a water contamination event within the public distribution network, the continuous improvement of an early warning system and the development of new real time water monitoring methods are essential. In this paper, the development of a new method for the measurements of aqueous samples by means of the Differential ion Mobility Spectrometry (DMS), also known as High Field Asymmetric waveform Ion Mobility Spectrometry (FAIMS) is described. The presented method involves nebulisation of the liquid sample by the nano electro spray ionisation (nano‐ESI) source with the subsequent desolvation of the analyte and ionisation by a 63Ni source.