Analytical Instrument Documents

Tomatoes are rich in lycopene, a hydrocarbon antioxidant that is the source of the red coloring in ripe tomatoes. The potential benefits of nutritional antioxidants such as lycopene have received a great deal of attention in the popular media. A piece of tomato skin was placed in front of the DART and the positive-ion mass spectrum was recorded.

There has been a recent trend in mass spectrometry towards the development of “open-air” ionization sources. These techniques allow for the rapid analysis of samples at atmospheric pressure with little or no sample preparation. The Direct Analysis in Real Time (DART™) ion source, which is ideal for the analysis of small molecules, represents the first and simplest of the open-air techniques.1 This source creates ions based on the interactions of long-lived excited state neutral atoms or molecules (“metastables”) with the sample and atmospheric gases.

The AccuTOF time-of-flight mass spectrometer equipped with Direct Analysis in Real Time (DART™) has been used to detect a wide variety of explosives in or on a variety of materials ranging from solutions to samples deposited on surfaces ranging from ABS plastic to metal, clothing and cardboard. Detection is rapid, specific, and sensitive.

Please see the following publication: “Versatile New Ion Source for the Analysis of Materials in Open Air under Ambient Conditions” Robert B. Cody, James A. Laramee and H. Dupont Durst, Analytical Chemistry 77 (8), 2297- 2302, 2005

DART provides very simple mass spectra that are free of multiple charging and alkali metal cation adducts such as [M+Na]+  and [M+K]. This facilitates identification of target compounds in mixtures and simplifies assignment of elemental compositions for unknowns.

Includes 44 application notes in the categories of Introduction and fundamentals, Drug Analysis, [Food, Flavors, and Fragrances], Forensics, Homeland Security, Industrial Materials, and Organic Chemistry.

In a recently published comparison of the ambient ionization techniques direct analysis in real time (DART™) and DESI, it was reported that a protonated molecule was not observed for DART, whereas the protonated molecule could be observed for DESI and DAPCI. This is an incorrect observation, resulting from the use of different experimental conditions for DART than were used for the other two techniques. Mass spectra of aspirin measured on a JEOL AccuTOF-DART™ mass spectrometer under the correct operating conditions are shown here. All assignments for the mass spectral peaks were confirmed by exact mass measurements.

Methamphetamine is a Schedule II Controlled Substance that is illegally manufactured in clandestine labs. There are several common synthetic pathways in use. For this study, methamphetamine was synthesized from phenyl-2-propanone by the (1) Leukart synthesis or (2) Reductive Amination, or from ephedrine or pseudoephedrine by the (3) Nagai, (4) Birch, and (5) Edme syntheses. Each of these reaction sequences resulted in unique impurity profiles1-3 that can be used by law enforcement to track the activities of clan labs, distribution networks, and trafficking patterns. The AccuTOF-DART was used to examine the starting materials, reaction mixtures, and final products from each reaction scheme.

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.

Fingerprints contain a great deal of chemical information that is not often exploited for forensic analysis. DART can detect and identify the chemical components of fingerprints, often providing information about what substances a subject has been handling.