What's New with DART?
The latest developments and news on DART® Mass Spectrometry
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Greetings!, We have some new data utilizing the Cerno BioScience MassWorks™ Software with the new DART GSX, showing the accurate mass capabilities of this combination. Additionally there are a number of interesting new DART publications on Heparin, Explosives, and Milk. Please have a look and contact me if you have any questions or comments. Thanks. Regards,  Brian Musselman President and CEO IonSense, Inc.
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Accurate Mass DART on a Quadrupole MS
The DART GSX System, which is based on the Agilent GC/MSD, can rapidly screen for unwanted materials such as pesticides or phthalates in a matter of seconds. However, there are times when higher specificity is needed, beyond the nominal mass accuracy provided by the MSD analyzer. Using the MassWorks Software, provided by Cerno Biosciences, this data can be converted to accuracies of  a few milliDaltons, greatly enhancing specificity and aiding in identification. Calibrating the spectra is simple and fast. The user loads the file containing the calibration mix (PFTBA) and a list of standard ions, then adjusts the peak selection to include isotope patterns. From this point the user could calibrate with the default parameters or adjust a few parameters if necessary. This system and software were utilized for identifying pesticides and phthalates in herbal supplements. A methanol extract of a ground Black Cohosh herbal supplement was used for this study. Four samples were each spiked with 1 PPM of the following phthalates or pesticides, DPP, BBP, Methamidophos and Acephate. The samples were then analyzed on the DART GSX at 250C using foam swabs dipped in the solution. The analysis of the 4 analytes was very quick, and the total run time including the calibrant was 3.5 minutes. After the calibration was run the values were recorded and the results are shown below. |
Sample
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Nominal Mass
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Exact Mass
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Accurate Mass
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mDA
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Methamidophos
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142.0
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142.0091
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142.0138
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4.6
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Acephate
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184.0
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184.0197
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184.0122
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7.5
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DiButyl Phthalate
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279.1
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279.1596
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279.1545
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5.1
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Benzyl Butyl Phthalte
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313.1
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313.1439
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313.1305
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13.4
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With the increase in mass accuracy, the confidence is greatly increased in specifying the presence of a contaminant. In addition an unknown compound may sometimes be identified due to its match in a formula search. |
DART on Your GC/MS -- Test Your Samples on the NEW DART GSX
 | | The DART GSX System |
The new DART-GSX System enables rapid screening and characterization of samples on the Agilent GC/MSD, which is widely used in many of your labs For details on the GSX, you can download the brochure here The DART GSX System can be fitted to one of your existing Agilent GC/MSD instruments or it can be supplied as a complete system with a new or refurbished Agilent GC/MSD. If you are interested in having samples run on the demonstration unit in Saugus or want to learn about the DART GSX Early Access Program, please let us know. |
Recent DART Publications
Sensors with high chemical specificity and enhanced sample throughput are vital to screening food products and medical devices for chemical or biochemical contaminants that may pose a threat to public health. For example, the rapid detection of oversulfated chondroitin sulfate (OSCS) in heparin could prevent reoccurrence of heparin adulteration that caused hundreds of severe adverse events including deaths worldwide in 2007-2008. Here, rapid pyrolysis is integrated with direct analysis in real time (DART) mass spectrometry to rapidly screen major glycosaminoglycans, including heparin, chondroitin sulfate A, dermatan sulfate, and OSCS. The results demonstrate that, compared to traditional liquid chromatography-based analyses, pyrolysis mass spectrometry achieved at least 250-fold higher sample throughput and was compatible with samples volume-limited to about 300 nL. Pyrolysis yielded an abundance of fragment ions (e.g., 150 different m/z species), many of which were specific to the parent compound. Using multivariate and statistical data analysis models, these data enabled facile differentiation of the glycosaminoglycans with high throughput. After method development was completed, authentically contaminated samples obtained during the heparin crisis by the FDA were analyzed in a blinded manner for OSCS contamination. The lower limit of differentiation and detection were 0.1% (w/w) OSCS in heparin and 100 ng/μL (20 ng) OSCS in water, respectively. For quantitative purposes the linear dynamic range spanned approximately 3 orders of magnitude. Moreover, this chemical readout was successfully employed to find clues in the manufacturing history of the heparin samples that can be used for surveillance purposes. The presented technology and data analysis protocols are anticipated to be readily adaptable to other chemical and biochemical agents and volume-limited samples.
Edward Sisco, Jeffrey Dake, Candice Bridge University of Maryland College Park, Department of Chemistry and Biochemistry, Chemistry Building, College Park, MD 20742, , United States Army Criminal Investigation Laboratory, Gillem Enclave, GA 30297 Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques . This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed.
Vojtech Hrbeka, Lukas Vaclavika, Ondrej Elichb, Jana Hajslova
Institute of Chemical Technology Prague, Faculty of Food and Biochemical Technology, Department of Food Analysis and Nutrition, Technicka 5, 166 28 Prague 6, Czech Republic, Diary Research Institute, Ke Dvoru 12a, 160 00 Prague 6, Czech Republic
The potential of direct analysis in real time (DART) ambient ionization technique coupled with high resolution mass spectrometry (HRMS) in authentication of milk and dairy products was critically assessed. In particular case, DART-HRMS was used for several scenarios: (i) discrimination among milks obtained from various farm animal species (cow, goat, and sheep), (ii) discrimination between cows´ milk produced in conventional and organic farming, and, (iii) detection of vegetable oil added to a milk-based product (soft cheese). For this purpose, a rapid profiling procedure based on examination of milk/cheese toluene extracts, was implemented. The obtained triacylglycerol (TAG) profiles (mass spectra) were processed with principal component analysis (PCA) and linear discriminant analysis (LDA). Based on LDA model, reliable differentiation of cows´ milk samples and goats'/sheep's milk was possible. The DART-HRMS procedure also allowed distinguishing milk mixtures prepared at adulteration level of 50% (v/v). The capability to recognize milk from conventional and organic farming was rather low, poor classification rates of the LDA model were obtained. On the other hand, reliable detection of the presence of vegetable oils (rapeseed, sunflower, and soybean), added to soft cheese at amount as low as 1% (w/w), was possible. Additionally, the quality of added oil in terms of degree of its oxidation could be documented.
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About IonSense
IonSense, Inc. provides OpenSpot Mass Spectrometry™ solutions to the fields of food safety, forensics, drug development, and chemical analysis. They 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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