A Proton Transfer Reaction-Quadrupole interface Time-Of-Flight Mass Spectrometer (PTR-QiTOF): High speed due to extreme sensitivity

作者：Sulzer Philipp^*; Hartungen Eugen; Hanel Gernot; Feil Stefan; Winkler Klaus; Mutschlechner Paul; Haidacher Stefan; Schottkowsky Ralf; Gunsch Daniel; Seehauser Hans; Striednig Marcus; Juerschik Simone; Breiev Kostiantyn; Lanza Matteo; Herbig Jens; Maerk Lukas; Maerk Tilmann D; Jordan Alfons

来源：International Journal of Mass Spectrometry, 2014, 368: 1-5.

DOI：10.1016/j.ijms.2014.05.004

• PTR-TOFMS
• PTR-MS
• TOF
• High sensitivity
• Trace gas analysis
• Direct injection mass spectrometry

Here we introduce a new prototype of a Proton Transfer Reaction-Time-Of-Flight Mass Spectrometry (PTR-TOFMS) instrument. In contrast to commercially available PTR-TOFMS devices so far, which utilize a transfer lens system, the novel prototype is equipped with a quadrupole ion guide for the highly effective transfer of ions from the drift tube to the mass spectrometer; hence we call it PTR-QiTOF, whereas %26quot;Qi%26quot; stands for %26quot;Quadrupole interface%26quot;. This new interface greatly improves the TOF mass resolution because of favorable injection conditions. Depending on whether we optimize the PTR-QiTOF to maximum sensitivity or maximum mass resolution, we get about 6900 and 10,400 m/Delta m mass resolution, respectively, already at m/z 149 (increasing with ascending masses). Furthermore, we increase the pressure in the drift tube from typically 2.2 mbar to 3.8 mbar and the drift tube voltage from 600V to 1000V. We directly compare the sensitivities of a commercial state-of-the-art PTR-TOFMS instrument to this %26quot;high pressure%26quot; PTR-QiTOF prototype and find that these modifications lead to a gain on average by a factor of 25 in terms of sensitivity with a maximum of about 4700 cps/ppbv for dichlorobenzene at m/z 147 for the PTR-QiTOF. This is (to our knowledge) the highest sensitivity ever reported for a PTR-MS instrument, regardless of the employed mass spectrometer. The increased sensitivity also has a very positive effect on the detection limit, which lies now at about 20 pptv with 100 ms and 750 ppqv after 1 min integration time. We provide data on the linearity of the instrumental response over a concentration range of five orders of magnitude and evaluate the prototype%26apos;s performance in a real-life test by analyzing the dynamic headspace of a minute amount of trinitrotoluene using only 2 s integration time.

• 出版日期2014-7-15