A portable system (10) is disclosed for collecting a sample from exhaled breath of a subject. The sample is collected for drug detection using mass-spectroscopy. The system comprises a sampling unit (14) and a housing (12) holding the sampling unit (14). The sampling unit (14) comprises an electrostatic filter membrane (13) that collects non-volatile drug substances from the exhaled breath. The housing (12) has an inlet (15) and an outlet (16).
