WHAT'S NEW WITH DART MS?                                         December 2013 
 The Latest Developments in Direct Analysis in Real Time Mass Spectrometry 

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We would like to wish you all the best for the Holiday Season and thank you for your interest in DART this past year. 

We have some recent results on SPME-DART to present, and your colleagues have published a number of new and interesting papers.

Please have a read and feel free to contact me if you have any questions or comments.  Thanks.


Brian Musselman, Ph.D.
President and CEO

Recent Results on Multi-Phase SPME-DART-MS for Increased Coverage and Sensitivity
 We have been investigating ways to improve the sensitivity and coverage of the DART analysis of contaminants and residues in complex matrices like food and fluids.  Though DART can excel at the direct analysis, we looked at how some simple extraction procedures may greatly improve the quality of the analytical measurements.

Here we looked into using multiple phases of solid phase extraction material to see the possible increase in coverage for pesticides in juice.  We used Supelco LC-Probes which are 45 micron SPE coated fibers designed to collect samples for LC/MS analysis.  Three fibers with different coatings including; PDMS-DVB, SCX and C-18 coating were used to enable differential capture of the target compounds.

The probes were inserted into the spiked cranberry juice.  Then each probe was removed from the sample, rinsed with water to remove soluble molecules like carbohydrates, and then positioned between DART source and MS.  The spectra at the right were obtained in a few seconds.

It is clear the the use of multiple phases increases coverage and should also improve the sensitivity.

If you or an associate would like us to analyze a few samples with our Thermo EXACTIVE+ we are looking for problems to challenge this exciting combination of SPME and DART technology.   Please contact me directly for information or a discussion.

Recent Publications on DART MS

Ashton D. Lesiak, Kendra J. Adams, Marek A. Domin, Colin Henck, Jason R. E. Shepard
Department of Chemistry, University at Albany, State University of New York (SUNY), Albany, NY; Mass Spectrometry Center, Merkert Chemistry Center, Boston College, Chestnut Hill, MA

Dimethylamylamine (DMAA) is a sympathomimetic amine found in weight-loss/workout supplements or used as an appetite suppressant. DMAA is a stimulant that is banned by the World Anti-Doping Agency (WADA). Adverse health effects as well as fatalities have been implicated with its use. Direct analysis in real time mass spectrometry (DART-MS) is an ambient ionization method that was employed to rapidly identify the presence of DMAA in various samples without any extraction or preparations whatsoever. DMAA was first identified in supplements, sampled directly in their solid forms. Furthermore, DMAA was detected directly in urine over 48 h as a means of indicating recent abuse of the substance. DART-MS analysis is instantaneous, and coupled with the high mass accuracy associated with the time-of-flight mass analyzer, results in unequivocal identification of the presence of DMAA. These features demonstrate DART-MS as an attractive potential alternative screening method for the presence of drugs and medications or for toxicological investigations.

R. Paseiro-Cerrato, G. O. Noonan & T. H. Begley
Department of Analytical Chemistry, Nutrition and Food Science. Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela E-15782, Spain; US FDA, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, MD 20740, USA

Primary aromatic amines (PAAs) are a group of substances with undesirable health effects, that are used in a variety of commercial products. Several recent studies, using a number of screening and confirmatory methods, have reported the migration of PAAs from some kitchen utensils into acetic acid 3% (w/v). Many of these methods require significant sample preparation, therefore the aim of this work was to determine if direct analysis in real time mass spectrometry (DART-MS) could be utilized as a rapid screening tool for the determination of PAAs in kitchen utensils. DART-MS results from direct analysis of the utensil have been compared with results of PAA migration by ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. The UPLC-MS/MS method had excellent linearity, appropriate sensitivity (LOD ≤ 1.5 µg L−1; LOQ ≤ 4.5 µg L−1), repeatability from 2.4 to 13.2% and acceptable recoveries. DART-MS results were in good agreement with UPLC-MS/MS data, with 100% of non-compliant (PAA positive) samples successfully identified by DART-MS.

Prabha Dwivedi, Daniel B. Gazda, Joel D. Keelor, Thomas F. Limero, William T. Wallace, Ariel V. Macatangay, and Facundo M. Fernández
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States; Wyle Science, Technology and Engineering Group, Houston, Texas 77058, United States; NASA Johnson Space Center, Houston, Texas 77058, United States

The development of a direct analysis in real time-mass spectrometry (DART-MS) method and first prototype vaporizer for the detection of low molecular weight (30-100 Da) contaminants representative of those detected in water samples from the International Space Station is reported. A temperature-programmable, electro-thermal vaporizer (ETV) was designed, constructed, and evaluated as a sampling interface for DART-MS. The ETV facilitates analysis of water samples with minimum user intervention while maximizing analytical sensitivity and sample throughput. The integrated DART-ETV-MS methodology was evaluated in both positive and negative ion modes to (1) determine experimental conditions suitable for coupling DART with ETV as a sample inlet and ionization platform for time-of-flight MS, (2) to identify analyte response ions, (3) to determine the detection limit and dynamic range for target analyte measurement, and (4) to determine the reproducibility of measurements made with the method when using manual sample introduction into the vaporizer. Nitrogen was used as the DART working gas, and the target analytes chosen for the study were ethyl acetate, acetone, acetaldehyde, ethanol, ethylene glycol, dimethylsilanediol, formaldehyde, isopropanol, methanol, methylethyl ketone, methylsulfone, propylene glycol, and trimethylsilanol.

Shanshan Zeng, Lu Wang, Teng Chen, Haibin Qu
Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China

A surface flowing mode sample holder was designed as an alternative sampling strategy for direct analysis in real time mass spectrometry (DART-MS). With the sample holder, the on-line coupling of macroporous resin column chromatography with DART-MS was explored and the then achieved through the sample holder. This new hyphenated system was employed to monitor the column chromatography elution process of Panax notoginseng's column chromatography. The effluent from macroporous resin column was first diluted and then mixed with a derivatization reagent on-line, and. After that, the mixture was then directly transferred into the ionization region of DART-MS by the sample holder. Notoginsenosides were methylated and ionized in a metastable helium gas stream, and was introduced then led into MS for the detection. Theis on-line system showed reasonable repeatability with the a relative standard deviations of 12.3% for the peak area. Three notoginsenosides, including i.e. notoginsenoside R1, ginsenoside Rb1 and ginsenoside Rg1, were simultaneously determined during the eluting process. The alteration of the chemical composition in the effluent was rapidly and accurately identified in 9 min, which agreed agreeing well with the off-line analysis determination output. Compared with UPLC method, The presented technique is was more sensitive and convenient compared to the traditional UPLC method. This studyThese results suggested that the surface flowing mode DART-MS could be used for has a good potential for the on-line process monitoring in the pharmaceutical industry.

About IonSense
IonSense, Inc. provides OpenSpot Mass Spectrometry™ solutions to the fields of food safety, forensics, drug development, and chemical analysis. We manufacture and develop direct analysis in real time (DART®) technology licensed from JEOL USA, Inc. and atmospheric solids analysis probe (ASAP™) licensed from M&M Consulting.

DART and ASAP Sources are available for most commercial LC/MS systems.  Look here to see if your system is DART-ready.  And  check here to see if your system is ASAP-ready.

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