scholarly journals Development of a Particle-Trap Preconcentration-Soft Ionization Mass Spectrometric Technique for the Quantification of Mercury Halides in Air

2015 ◽  
Vol 87 (10) ◽  
pp. 5109-5116 ◽  
Author(s):  
Daniel A. Deeds ◽  
Avik Ghoshdastidar ◽  
Farhad Raofie ◽  
Élise-Andrée Guérette ◽  
Alain Tessier ◽  
...  
Keyword(s):  
Mass Spectrometric ◽  
Ionization Mass ◽  
Soft Ionization ◽  
Spectrometric Technique ◽  
Mass Spectrometric Technique ◽  
Mercury Halides ◽  
Particle Trap

scholarly journals Ground-based intercomparison of two isoprene measurement techniques

2002 ◽  
Vol 2 (3) ◽  
pp. 905-920
Author(s):  
E. Leibrock ◽  
L. G. Huey ◽  
P. D. Goldan ◽  
W. C. Kuster ◽  
E. Williams ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Chemical Ionization ◽  
Measurement Techniques ◽  
Mass Spectrometric ◽  
Ionization Mass ◽  
Chromatographic Technique ◽  
Field Site ◽  
Air Masses ◽  
Spectrometric Technique ◽  
Mass Spectrometric Technique

Abstract. An informal intercomparison of two isoprene (C5H8) measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS) was compared to a well-established gas chromatographic technique (GC). The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an interference associated with air masses from the Denver, CO metropolitan area. However, the CIMS technique is also demonstrated to be sensitive and fast and is a candidate for isoprene measurements in remote environments near isoprene sources.

scholarly journals Ground-based intercomparison of two isoprene measurement techniques

2003 ◽  
Vol 3 (1) ◽  
pp. 67-72 ◽  
Author(s):  
E. Leibrock ◽  
L. G. Huey ◽  
P. D. Goldan ◽  
W. C. Kuster ◽  
E. Williams ◽  
...  
Keyword(s):  
Chemical Ionization ◽  
Measurement Techniques ◽  
Mass Spectrometric ◽  
Ionization Mass ◽  
Chromatographic Technique ◽  
Field Site ◽  
Air Masses ◽  
Spectrometric Technique ◽  
Mass Spectrometric Technique ◽  
Tandem Mass Spectrometric

Abstract. An informal intercomparison of two isoprene (C5H8) measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS) was compared to a well-established gas chromatographic technique (GC). The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an anthropogenic interference associated with air masses from the Denver, CO metropolitan area as well as an additional interference occurring in clean conditions. However, the CIMS technique is also demonstrated to be sensitive and fast. Especially after introduction of a tandem mass spectrometric technique, it is therefore a candidate for isoprene measurements in remote environments near isoprene sources.

scholarly journals Demystifying and Unravelling the Factual Molecular Structure of the Biopolymer Sporopollenin

2019 ◽  
Author(s):  
Abanoub Mikhael ◽  
Kristina Jurcic ◽  
Celine Schneider ◽  
David carr ◽  
Gregory L. Fisher ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Nuclear Magnetic Resonance ◽  
Chemical Structure ◽  
Pollen Grains ◽  
Outer Wall ◽  
Mass Spectrometric ◽  
Chemical Degradation ◽  
Ionization Mass ◽  
Soft Ionization ◽  
Biochemical Pathways

<p></p><p>Sporopollenin is a natural, highly cross-linked biopolymer composed of carbon, hydrogen, and oxygen, which forms the outer wall of pollen grains. Sporopollenin is resilient to chemical degradation.<sup> </sup>Because of this stability, its exact chemical structure and the biochemical pathways involved in its biosynthesis remains a mystery and unresolved.<sup> </sup></p> <p>We have identified and characterized the molecular structure of the clean, intact sporopollenin using soft ionization mass spectrometric and nuclear magnetic resonance techniques. These analyses showed that sporopollenin contained a poly(hydroxyacid) dendrimer-like network, which accounted for the sporopollenin empirical formula. In addition, the identified hydroxy acid monomers contained a beta diketone moiety, which most probably accounts for the known antioxidant activity of sporopollenin. Moreover, our elucidation studies allowed us to identify a unique circular polyhydroxylated tetraketide polymer. This polymer acted as the rigid backbone on which the poly(hydroxyacid) network can be built, forming the scaffold of the spherical sporopollenin exine.</p><br><p></p>

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