Liquid trap or separator for electrosurgical applications

Apparatus for mass spectrometry and/or ion mobility spectrometry comprising:

• a first device arranged and adapted to generate aerosol, smoke or vapour from a target;
• a mass and/or ion mobility analyser;
• one or more second devices arranged and adapted to aspirate aerosol, smoke or vapour and/or liquid to or towards the analyser;
• and
• a liquid trap or separator located between said first device and said mass and/or ion mobility analyser, wherein said liquid trap or separator comprises a liquid collector or drain and a liquid detector arranged and adapted to detect aspirated liquid, wherein said liquid trap or separator is arranged and adapted to capture and/or discard liquid aspirated by said one or more second devices and wherein said liquid trap or separator is further arranged and adapted such that when said liquid detector detects aspirated liquid then said liquid trap or separator is arranged and adapted to divert at least some of said liquid to said liquid collector or drain.