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


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Greetings!


We are getting ready for the upcoming Recent Advances in Food Analysis (RAFA 2013) meeting in Prague next month and have some details below.  We have also extended out relationship with Thermo to sell DART, and there are some interesting new publications.

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


Regards,

Brian Musselman, Ph.D.
President and CEO

Recent Advances in Food Analysis (RAFA 2013)
 We will be attending the upcoming  6th International Symposium on Recent Advances in Food Analysis in Prague November 5-8, and welcome you to visit, if you are attending. 

Together with our partner KR Analytical, we are also hosting a seminar on November 6 titled, "Enhancing the Value of Direct Analysis in Real Time (DART) MS Leveraging Sorbent Technologies."  You can see the agenda here


ID-CUBE Available with Orbitrap MS Systems

Through our new arrangement with ThermoFisher Scientific you can now get the Q-Exactive™ and
ID-CUBE on the Exactive Plus
Exactive™ Plus LC-MS systems shipped from the Thermo factory equipped with the ID-CUBE ion source.  This will provide a single point of contact for the purchase, installation, and support for the system.

With the ID-CUBE source, a drop of sample is placed on the OpenSpot™ Sample Card which is then inserted into the source.  The screen is quickly heated and the sample ionized, providing for for rapid pesticide detection, forensics identification, and screening for product quality. 

Here is an application showing the capabilities of DART coupled with an Orbitrap mass spectrometer.  High-Throughput Food Safety Control Employing Real Time Ionization (DART) Coupled to Orbitrap High-Resolution Mass Spectrometry

The Q Exactive LC-MS system combines quadrupole precursor selection with high-resolution, accurate-mass Orbitrap detection designed for high-confidence identification, quantitation and confirmation. The Thermo Scientific Exactive Plus Orbitrap LC-MS is a benchtop instrument designed for high-performance screening, compound identification and quantitation.
Recent Publications on DART MS


Capabilities and limitations of direct analysis in real time orbitrap mass spectrometry and tandem mass spectrometry for the analysis of synthetic and natural polymers

Maxime C. Bridoux, Xavier Machuron-Mandard
CEA, DAM, DIF, Arpajon, France

RATIONALE. Despite the widespread use of direct analysis in real time mass spectrometry (DART-MS), its capabilities in terms of accessible mass range and the types of polymers that can be analysed are not well known. The goal of this work was to evaluate the capabilities and limitations of this ionization technique combined with orbitrap mass spectrometry and tandem mass spectrometry, for the characterization (structural and polydispersity metrics) of various synthetic and natural polymers.
METHODS. The capabilities and limitations of DART-MS (and -MS2), using an orbitrap mass spectrometer, for polymer analysis were evaluated using various industrial synthetic polymers and biopolymers. Stainless steel mesh screens secured on a movable rail were used as the sampling surface, onto which 5 μL of various polymers dissolved in tetrahydrofuran were added. Assignment of spectral features and calculation of molecular weight and polydispersity metrics were performed using Polymerix™ software and the results were compared with those obtained by gel-permeation chromatography (GPC).
RESULTS. Protonated oligomers and ammonium adducts were instantaneously detected as the major ionisation products in positive ion mode. Only perfluoropolyethers (PFPEs) were ionised in negative mode and detected as [M]-. ions. Only singly charged molecular species were observed for all oligomers under study, allowing for a rapid determination of the molecular weight and polydispersity metrics of polymers. At elevated DART gas temperatures (400-500C) the molecular weight and polydispersity metrics compared fairly well with those obtained by GPC, with polymers whose masses ranged from 200 g.mol-1 to 4000 g.mol-1.
CONCLUSIONS. DART-MS allowed the direct and rapid analysis (mass spectra and tandem mass spectra of all the polymers were acquired in seconds) based on the exact masses of their [M+H]+ and [M+NH4]+ ions (in the positive mode) or [M]-. ions (for polymers having a high sensitivity toward electron-capture ionisation such as PFPEs), as well as the exact masses of their product ions, for both synthetic and natural polymers under ambient conditions without any sample pre-treatment.


Joseph R. Swider
The McCrone Group, Westmont, IL

The use of a direct analysis in real time (DART) mass spectrometer (MS) instrument was optimized for 22 compounds of organic explosive residues to provide a guide for DART-MS users in rapid screening of explosive compounds. Samples were introduced as neat solutions and sequential dilutions to determine optimal instrument conditions and lowest concentration detectable. Most compounds were optimized to 250C in the negative ion mode, and several compounds benefited from the addition of a chloride dopant from methylene chloride (amino-dinitrotoluenes, RDX, EGDN, and PETN). Few compounds were more sensitive in the positive ion mode (TEGDN, DEGDN, HNS, and DMNB). Mixtures of compounds were detected using clean room wipes, directly from their surfaces and from subsequent extractions. Compounds from the mixtures were also successfully detected in soil and from swipes of spiked surfaces. The instrument showed merit in detection of pg/μL solutions for most of the compounds and among the substrates tested.


Yang Wanga, Li Liua, Li Mab, Shuying Liua
Jilin Ginseng Academy, Changchun University of Chinese Medicine, Jilin, Changchun 130117, China, School of Environmental Air Security and Pollution Control Engineering, Jinan University, Guangzhou 510632, China

Direct analysis in real time (DART) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF-MS) was applied to investigate the different types of saccharides including ginseng oligosaccharide extract with minimal sample pretreatment. Helium gas temperature into the DART ion source was adjusted to find optimal ionization temperature for glucose in increments of 50 C from 50 C to 450 C. It was observed that gas temperature had a significant effect on signal intensity in DART mass spectra. The temperature for the glucose ionization should be at least 150 C, and the signal intensity reached optimal ionization state at 250 C. With the increase of a sugar chain, a higher gas temperature was needed for saccharide ionization. Interestingly, sugar cluster formation can be observed at 450 C for disaccharides and trisaccharides. It is found that the [M+NH4]+ ions of trisaccharide and ginseng oligosaccharides can be rarely produced without any derivatization even at 450 C. All the samples except five carbon monosaccharides can generate the m/z 198 ion, so it is difficult to determine whether a m/z 198 ion is the [M+NH4]+ ion of glucose or merely a sample fragment ion most likely an ammoniated monosaccharide fragment.
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.

Phone - 781.484.1043  | info@ionsense.com | http://www.ionsense.com
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