Gas chromatography combined with fast flow glow discharge mass spectrometry (GC-FFGD-MS)

A low power ( <5 W) dc fast flow glow discharge (FFGD) ion source has been adapted for the detection of halogenated hydrocarbons using gas chromatography as the sample introduction technique. A simple and robust interface design enabled direct coupling of the ion source to a common gas chromatograph. After optimisation, detection limits for four compounds were from 0.3 - 66.5 pg ( by monitoring the halogen ions Cl-35, Br-79 and I-127). The source operating conditions can be 'tuned' to obtain different information, allowing both sensitive elemental detection and structure elucidation using a single instrument, with sub-pg detection limits for the bromobenzene molecular ion. The source pressure, power and discharge gas flow rate were found to have significant effects on the relative fragment ions detected. These observations can be rationalised using neutral, excited state chemistry.