A NEW GRIDLESS ION OPTICS FOR HIGH RESOLUTION TIME-OF-FLIGHT MASS SPECTROMETER

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2621-2626 ◽  
Author(s):  
A. BHOWMICK ◽  
W. C. J. CARVALHO ◽  
A. V. KORGAONKAR ◽  
J. V. YAKHMI ◽  
V. C. SAHNI

Wire meshes commonly used as transmission grids in ion optical configurations has certain unavoidable disadvantages. Apart from the loss in transmission, there are small angle deflections while the ions are passing close to the wires. This is important for high resolution time-of-flight mass spectrometry as this effect impairs both the dynamic range and the resolution. The amount of deflection from various commercially available grids are determined from simulation calculations on representative wire grids. Gridless designs of ion optics are becoming more popular in recent times for sophisticated and sensitive measurements. Here we report such a device for time of flight mass spectrometer that also assists in perpendicular ionization. This ion optics together with a gridless ion reflector gives a high time resolution of more than 40000.

2010 ◽  
Vol 82 (20) ◽  
pp. 8456-8463 ◽  
Author(s):  
Shuichi Shimma ◽  
Hirofumi Nagao ◽  
Jun Aoki ◽  
Keiji Takahashi ◽  
Shinichi Miki ◽  
...  

2016 ◽  
Author(s):  
Lei Yao ◽  
Ming-Yi Wang ◽  
Xin-Ke Wang ◽  
Yi-Jun Liu ◽  
Hang-Fei Chen ◽  
...  

Abstract. Amines and amides are important atmospheric organic-nitrogen compounds but high time resolution, highly sensitive, and simultaneous ambient measurements of these species are rather sparse. Here, we present the development of a high resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) method utilizing protonated ethanol as reagent ions to simultaneously detect atmospheric gaseous amines (C1 to C6) and amides (C1 to C6). This method possesses sensitivities of 5.6–19.4 Hz pptv−1 for amines and 3.8–38.0 Hz pptv−1 for amides under total reagent ion signals of ~ 0.32 MHz, and detection limits of 0.10–0.50 pptv for amines and 0.29–1.95 pptv for amides at 3σ of the background signal for a 1-min integration time, respectively. Controlled characterization in the laboratory indicates that relative humidity has significant influences on detection of amines and amides, whereas the presence of organics has no obvious effects. Ambient measurements of amines and amides utilizing this method were conducted from 25 July 2015 to 25 August 2015 in urban Shanghai, China. While the concentrations of amines ranged from a few pptv to hundreds of pptv, concentrations of amides varied from tens of pptv to a few ppbv. Among the C1- to C6-amines, the C2-amines were the dominant species with concentrations up to 130 pptv. For amides, the C3-amides (up to 8.7 ppb) were the most abundant species. The diurnal profiles of amines and amides suggest that in addition to the secondary formation of amides in the atmosphere, industrial emissions could be important sources of amides in urban Shanghai. During the campaign, photo-oxidation of amines and amides might be a main loss pathway for them in day time, and wet deposition was also an important sink.


2007 ◽  
Vol 89 (4) ◽  
pp. 453-457 ◽  
Author(s):  
S.D. Kraft ◽  
J. Mikosch ◽  
P. Staanum ◽  
J. Deiglmayr ◽  
J. Lange ◽  
...  

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