Development of a time-of-flight mass spectrometer combined with an ion-attachment method for multicomponent gas analysis

Abstract

We developed a new mass spectrometer that can analyse multicomponent gases without fragmentation. This is essentially a time-of-flight (TOF) mass analyser in which the ion attachment method is used for ionisation. The method using this new device is referred to as “time-of-flight analysis in combination with ion-attachment” (TOFIA). TOFIA has the capability to analyse breath gas in about 10 min using the radio-frequency (RF) ion-guiding method and a multichannel scaler (MCS). The mass resolution of the trial device was unsatisfactory, but the device can be greatly improved in the future. We successfully analysed exhaled breath gases related to diseases, including ammonia, acetone, and isoprene gases. We expect that the TOFIA device developed in this work will contribute significantly to studies on the relationship between breath gas and health.

Comparison of Cu+, Ag+, and Au+ Ions as Ionization Agents of Volatile Organic Compounds at Subatmospheric Pressure

“…Reactions at low pressures (≲10 –7 Torr) led to fragmentation of the examined compounds, while at higher pressures bonding of one or more molecules to the metal ion was observed, providing molecular weight information. Later, Li + ions produced inside the thermionic source were used for ionizing organic compounds by forming simple ion–molecular complexes in the gas phase. , Cu + ions produced by laser ablation in a laser plasma ion source were used for the detection of octane and trinitrotoluene in the gas phase, and the reaction time of the complex formation between Cu + ion and organic molecules was estimated to be about 1 ms at a pressure of 0.3 Torr . In both these examples, complexes containing molecules of water, [M + H 2 O] + , [M + 2H 2 O] + , and [M + VOC + H 2 O] + , were also present in the spectra, which was similar to our previous work with Au + ions.…”