کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1196120 964455 2007 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Probing the Mechanisms of an Air Amplifier Using a LTQ-FT-ICR-MS and Fluorescence Spectroscopy
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Probing the Mechanisms of an Air Amplifier Using a LTQ-FT-ICR-MS and Fluorescence Spectroscopy
چکیده انگلیسی

We report the first quantitative assessment of electrosprayed droplet/ion focusing enabled by the use of a voltage-assisted air amplifier between an electrospray ionization emitter and a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer (ESI-LTQ-FT-ICR-MS). A solution of fluorescent dye was electrosprayed with a stainless steel mesh screen placed in front of the MS inlet capillary acting as a gas-permeable imaging plate for fluorescence spectroscopy. Without use of the air amplifier, no detectable FT-ICR signal was observed, as well as no detectable fluorescence on the screen upon imaging using a fluorescence scanner. When the air amplifier was turned ON while electrospraying the fluorescent dye, FT-ICR mass spectra with high signal to noise ratio were obtained with an average ion injection time of 21 ms for an AGC target value of 5 × 105. Imaging of the screen using a fluorescence scanner produced a distinct spot of cross-sectional area ∼33.5 mm2 in front of the MS inlet capillary. These experimental results provide direct evidence of aerodynamic focusing of electrosprayed droplets/ions enabled by an air amplifier, resulting in improved electrospray droplet/ion capture efficiency and reduced ion injection time. A second set of experiments was carried out to explore whether the air amplifier assists in desolvation. By electrospraying a mix of quaternary amines, ratios of increasingly hydrophobic molecules were obtained. Observation of the solvophobic effect associated with electrospray ionization resulted in a higher abundance of the hydrophobic molecule. This bias was eliminated when the air amplifier was turned ON and a response indicative of the respective component concentrations of the molecules in the bulk solution was observed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the American Society for Mass Spectrometry - Volume 18, Issue 11, November 2007, Pages 1909–1913
نویسندگان
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