https://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloadshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/direct-analysis-of-organometallic-compounds7. Organic SynthesisWed, 04 Mar 2020 10:24:56 GMT

Organometallic compounds play an important role in chemistry, as recently recognized by the awarding of the 2005 Nobel Prize in Chemistry to Chauvin, Schrock and Grubbs. Characterization of organometallic compounds by mass spectrometry can sometimes be complicated by problems with solubility and reactivity. Electron ionization can be used for some voltatile organometallics. Fast atom bombardment (FAB) and electrospray ionization (ESI) are useful provided suitable solvents can be used. Field desorption (FD) is often effective, but FD emitters can be fragile and the analysis should be carried out by an experienced operator. DART (Direct Analysis in Real Time) complements these methods and provides an alternative; it is fast and does not require solvents. The sampling area is purged with an inert gas, reducing the likelihood of undesirable reactions. Further, AccuTOF-DART permits exact mass measurements without requiring the presence of a reference standard during the sample measurement. DART is extremely robust and does not require special operator training.

<p>Mass spectra of several organometallic compounds were obtained by using DART. A few dry particles of each compound were placed in front of the DART source on a melting point tube and mass spectra were obtained within seconds. The best results were obtained by using small quantities of sample; very large quantities can result in ion-molecule reactions between sample ions and sample neutrals, resulting in isotopic patterns characterized by both M⁺.and [M+H]⁺. All labeled assignments were confirmed by exact mass measurements and isotope pattern matching.</p> https://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/chemical-reaction-monitoring-with-the-accutof-dart-mass-spectrometer7. Organic SynthesisSun, 23 Feb 2020 15:01:48 GMT

DART provides a convenient means for monitoring the progress of chemical reactions. Reactants, intermediates, products and byproducts can be detected by simply dipping a glass rod into the reaction pot and then placing the rod in front of the DART ion source. The AccuTOF's ability to measure accurate masses and isotopic abundances makes it possible to confirm or identify the elemental compositions of peaks in the mass spectra. Here we show the use of AccuTOF-DART to monitor the acetylation of 1,2-hexanediol as a function of time.

<h3>Experimental</h3> <p>600 μl of 1,5-hexanediol (4.9 mmol) was mixed with 700 μl (12.3 mmol) of glacial acetic acid and one drop of concentrated sulfuric acid in a loosely capped scintillation vial. The reaction was slowly warmed with a heat gun and a fume vent was positioned over the reaction vial and the DART source. Samples were taken periodically for analysis with the AccuTOF-DART by sipping a melting point tube into the reaction mixture and placing the tube in front of the DART ion source for a few seconds. The reaction progress was monitored by plotting the fractional abundances of the protonated molecules (MH⁺) as measured for each component in the mass spectra.</p> https://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/analysis-of-highly-polar-compound-ionic-liquid-by-dart7. Organic SynthesisSun, 23 Feb 2020 10:44:49 GMT

Ionic liquids have drawn much attention from various engineering fields, such as tribology, because of their unique properties of electrical conductivity, extremely low vapor pressure, low viscosity, low combustibility, etc. The sample was analyzed by dipping a glass rod to the sample and presented it directly to the DART™ ion source.

<p>Ionic liquids have drawn much attention from various engineering fields, such as tribology, because of their unique properties of electrical conductivity, extremely low vapor pressure, low viscosity, low combustibility, etc. The sample was analyzed by dipping a glass rod to the sample and presented it directly to the DART™ ion source.</p>