JEOL Resourceshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-DownloadsAperture Size Influences Oxidation in Positive-Ion Nitrogen Direct Analysis in Real Time Mass Spectrometryhttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/aperture-size-influences-oxidation-in-positive-ion-nitrogen-direct-analysis-in-real-time-mass-spectrometryMass Spectrometry (MS)Fri, 10 Jun 2022 09:31:31 GMTDART mass spectrometry commonly uses helium as the DART gas. With the looming helium shortage, other gases are being evaluated for DART.<h2 id="Abstract">Abstract</h2> <p><img alt="Abstract Image" src="https://jeolusa.s3.amazonaws.com/resources_ai/778/js2c00115_0004.webp?AWSAccessKeyId=AKIAQJOI4KIAZPDULHNL&Expires=2145934800&Signature=t5k5xp460M0O%2FpxjhpIUM8offA0%3D" /></p> <p>Direct Analysis in Real Time (DART) mass spectrometry commonly uses helium as the DART gas. With the looming helium shortage, other gases are being evaluated for DART. Nitrogen is inexpensive and readily available, making it a desirable alternative. However, NO<sup>+</sup> reagent ions present in positive-ion nitrogen DART result in extensive oxidation for many compounds. The DART source uses a ceramic insulator cap to protect the operator from electrical shock. The most common cap has an aperture with a 2.5 mm inner diameter, through which the gas exits the DART source. By using a cap with a narrow (0.5 mm) ID, oxidation can be significantly reduced for nitrogen DART. The 0.5 mm cap is hypothesized to reduce back-diffusion of atmospheric oxygen into the DART source, with a reduction in the relative abundance of NO<sup>+</sup> and increase in the relative abundance of [(H<sub>2</sub>O)<sub>2</sub> + H]<sup>+</sup> as the reactive species responsible for ionization of the analytes.</p> <h3>To access this article, please click here:  <a href="https://doi.org/10.1021/jasms.2c00115" target="_blank" title="DOI URL">https://doi.org/10.1021/jasms.2c00115</a></h3> Integrated Data Analysis Making Use of the Total Information from Gas Chromatography and High-Resolution Time-of-Flight Mass Spectrometry to Identify Qualitative Differences Between Two Whisky Sampleshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/integrated-data-analysis-making-use-of-the-total-information-from-gas-chromatography-and-high-resolution-time-of-flight-mass-spectrometry-to-identify-qualiMS Peer-Reviewed ArticlesMon, 13 Dec 2021 11:49:42 GMTAnalysis of complex mixtures with gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC-HRTOFMS) can produce a large amount of data. A new software program was recently reported that integrates all of the available mass spectrometric information from GC-HRTOFMS analysis into a concise report. New capabilities have now been added to the software to incorporate retention index data and to identify differences between two samples.<h3>Abstract</h3> <h4>Rationale</h4> <p>Analysis of complex mixtures with gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC-HRTOFMS) can produce a large amount of data. A new software program was recently reported that integrates all of the available mass spectrometric information from GC-HRTOFMS analysis into a concise report. New capabilities have now been added to the software to incorporate retention index data and to identify differences between two samples.</p> <h4>Methods</h4> <p>Two Scotch whisky samples were sampled by solid-phase microextraction (SPME) and analyzed by GC-HRTOFMS. One of the two whisky samples (Sample B) was identical to the other sample (Sample A) except for an additional six months storage in sherry casks. Both electron ionization (EI) and chemical ionization (CI) data were obtained using a new GC-time-of-flight mass spectrometer system (JEOL AccuTOF GC-Alpha) with enhanced resolving power and mass accuracy. Statistical analysis of replicate measurements of the whisky samples was carried out with a new software program (msFineAnalysis version 3.2) to identify and assign differences between the samples.</p> <h4>Results</h4> <p>There were 124 peaks detected in the two whiskies. Thirteen compounds were detected with a relative peak area greater than 0.05% that were present in greater amounts in the whisky that was stored in sherry casks for an additional 6 months. Ten of these compounds were identified by the software with high confidence, two were identified as isomers with close retention indices, and one was identified interactively.</p> <h4>Conclusions</h4> <p>The software identified small differences between the two samples that resulted from sherry cask aging. Because all of the information available from the hard and soft ionization analyses for each compound is summarized in a concise integrated report, the operator can rapidly determine the level of confidence for each assignment and inspect the information for compounds that are not present in the database.</p> <h3>To read more please follow this link:  <a href="https://doi.org/10.1002/rcm.9225" target="_blank">https://doi.org/10.1002/rcm.9225</a></h3> Insights into Dodecenes Produced from Olefin Oligomerization Based on Two-Dimensional Gas Chromatography–Photoionization–Time of Flight Mass Spectrometry and Multivariate Statisticshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/insights-into-dodecenes-produced-from-olefin-oligomerization-based-on-two-dimensional-gas-chromatographyphotoionizationtime-of-flight-mass-spectrometry-andMass Spectrometry (MS)Fri, 12 Nov 2021 11:18:06 GMTCatalyzed light olefin oligomerization is widely used in petrochemical industries to produce fuels and chemicals. Light olefins such as propene and butenes are commonly selected as feedstocks. Solid phosphoric acid (SPA) and zeolite are representative acidic catalysts. Both the feedstocks and catalysts have an impact on the product composition. In this study, state-of-the-art instrumentation two-dimensional gas chromatography (GC × GC) coupled photoionization─time of flight mass spectrometry was employed to investigate the composition of dodecene products produced from olefin oligomerization. Information such as the olefin congener distribution, dodecene structural subgroup distribution, and individual dodecene isomers was obtained and utilized in the statistical analyses. By using specific data sets of the product composition, the distinguishment between SPA and zeolite catalysts as well as among the feedstocks was achieved by applying the unsupervised screening approaches (principal component analysis and hierarchical clustering analysis). The potential indicators of catalysts and feedstocks were selected by the feature selection methods (univariate analysis: analysis of variance and multivariate analysis: partial least squares-discriminant analysis).<h2>Abstract</h2> <p>Catalyzed light olefin oligomerization is widely used in petrochemical industries to produce fuels and chemicals. Light olefins such as propene and butenes are commonly selected as feedstocks. Solid phosphoric acid (SPA) and zeolite are representative acidic catalysts. Both the feedstocks and catalysts have an impact on the product composition. In this study, state-of-the-art instrumentation two-dimensional gas chromatography (GC × GC) coupled photoionization─time of flight mass spectrometry was employed to investigate the composition of dodecene products produced from olefin oligomerization. Information such as the olefin congener distribution, dodecene structural subgroup distribution, and individual dodecene isomers was obtained and utilized in the statistical analyses. By using specific data sets of the product composition, the distinguishment between SPA and zeolite catalysts as well as among the feedstocks was achieved by applying the unsupervised screening approaches (principal component analysis and hierarchical clustering analysis). The potential indicators of catalysts and feedstocks were selected by the feature selection methods (univariate analysis: analysis of variance and multivariate analysis: partial least squares-discriminant analysis)..</p> <h2>Click Link to View Article: <a href="https://doi.org/10.1021/acsomega.1c03328" target="_blank">https://doi.org/10.1021/acsomega.1c03328</a></h2> Non-targeted analysis of electronics waste by comprehensive two-dimensional gas chromatography combined with high-resolution mass spectrometry: Using accurate mass information and mass defect analysis to explore the datahttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/non-targeted-analysis-of-electronics-waste-by-comprehensive-two-dimensional-gas-chromatography-combined-with-high-resolution-mass-spectrometry-using-accuraMass Spectrometry (MS)Sat, 07 Mar 2020 18:48:34 GMTComprehensive two-dimensional gas chromatography (GC×GC) and high-resolution mass spectrometry (HRMS) offer the best possible separation of their respective techniques. Recent commercialization of combined GC×GC–HRMS systems offers new possibilities for the analysis of complex mixtures. However, such experiments yield enormous data sets that require new informatics tools to facilitate the interpretation of the rich information content. This study reports on the analysis of dust obtained from an electronics recycling facility by using GC×GC in combination with a new high-resolution time-of-flight (TOF) mass spectrometer. New software tools for (non-traditional) Kendrick mass defect analysis were developed in this research and greatly aided in the identification of compounds containing chlorine and bromine, elements that feature in most persistent organic pollutants (POPs). In essence, the mass defect plot serves as a visual aid from which halogenated compounds are recognizable on the basis of their mass defect and isotope patterns. Mass chromatograms were generated based on specific ions identified in the plots as well as region of the plot predominantly occupied by halogenated contaminants. Tentative identification was aided by database searches, complementary electron-capture negative ionization experiments and elemental composition determinations from the exact mass data. These included known and emerging flame retardants, such as polybrominated diphenyl ethers (PBDEs), hexabromobenzene, tetrabromo bisphenol A and tris (1-chloro-2-propyl) phosphate (TCPP), as well as other legacy contaminants such as polychlorinated biphenyls (PCBs) and polychlorinated terphenyls (PCTs).<p><strong>For more information:</strong> <a href="https://www.sciencedirect.com/science/article/abs/pii/S0021967315004604" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0021967315004604</a></p> Molecular Characterization of Volatiles and Petrochemical Base Oils by Photo-Ionization GC×GC-TOF-MShttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/molecular-characterization-of-volatiles-and-petrochemical-base-oils-by-photo-ionization-gcgc-tof-msMass Spectrometry (MS)Sat, 07 Mar 2020 18:46:35 GMTThe characterization of organic mixtures by comprehensive two-dimensional gas chromatography (GC×GC) coupled to electron impact (EI) ionization time-of-flight mass spectrometry (TOF-MS) allows the detection of thousands of compounds. However, owing to the exhaustive fragmentation following EI ionization, despite the use of mass spectral libraries, a majority of the compounds remains unidentified because of the lack of parent ion preservation. Thus, soft-ionization energies leading to organic compounds being ionized with limited or no fragmentation, retaining the molecular ion, has been of interest for many years. In this study, photoionization (PI) was evaluated as the ion source for GC×GC-TOF-MS measurements. First, capabilities and limitations of PI were tested using an authentic mixture of compounds of several chemical classes. Ionization energy exhibited by PI, equivalent to 10.8 eV, resulted in significant retention of molecular ion information; [M]+• for alkanes, ketones, FAMEs, aromatics, [M–H]+• for chloroalkanes, and [M–H2O]+• for alcohols. Second, considering the potential of PI for hydrocarbons, base oils, complex mixtures of saturated and unsaturated hydrocarbons blended for finished lubricant formulations, were extensively evaluated. Several chemical classes of hydrocarbons were positively identified including a large number of isomeric compounds, both aliphatics and cyclics. Interestingly, branched-alkanes were ionized with lower excess internal energy, not only retaining the molecular ions but also exhibiting unique fragmentation patterns. The results presented herein offer a unique perspective into the detailed molecular characterization of base oils. Such unprecedented identification power of PI coupled with GC×GC-TOF-MS is the first report covering volatiles to low-volatile organic mixtures.<p><strong>For more information:</strong> <a href="https://pubs.acs.org/doi/pdf/10.1021/acs.analchem.7b00124" target="_blank">https://pubs.acs.org/doi/pdf/10.1021/acs.analchem.7b00124</a></p> Compositional elucidation of heavy petroleum base oil by GC × GC‐EI/PI/CI/FI‐TOFMShttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/compositional-elucidation-of-heavy-petroleum-base-oil-by-gc-gceipicifitofmsMass Spectrometry (MS)Sat, 07 Mar 2020 18:44:19 GMTComprehensive two‐dimensional gas chromatography (GC × GC) coupled to time‐of‐flight mass spectrometry is a powerful separation tool for complex petroleum product analysis. However, the most commonly used electron ionization (EI) technique often makes the identification of the majority of hydrocarbons impossible due to the exhaustive fragmentation and lack of molecular ion preservation, prompting the need of soft‐ionization energies. In this study, three different soft‐ionization techniques including photo ionization (PI), chemical ionization (CI), and field ionization (FI) were compared against EI to elucidate their relative capabilities to reveal different base oil hydrocarbon classes. Compared with EI (70 eV), PI (10.8 eV) retained significant molecular ion (M+·) information for a large number of isomeric species including branched‐alkanes and saturated monocyclic hydrocarbons along with unique fragmentation patterns. However, for bicyclic/polycyclic naphthenic and aromatic compounds, EI played upper hand by retaining molecular as well as fragment ions to identify the species, whereas PI exhibited mainly molecular ion signals. On the other hand, CI revealed selectivity towards different base oil groups, particularly for steranes, sulfur‐containing thiophenes, and esters, yielding protonated molecular ions (M + H)+ for unsaturated and hydride abstracted ions (M‐H+) for saturated hydrocarbons. FI, as expected, generated intact molecular ions (M+·) irrespective to the base oil chemical classes. It allowed elemental composition by TOFMS with a mass resolving power up to 8000 (FWHM) and a mass accuracy of 1 mDa, leading to the calculation of heteroatomic content, double bond equivalency, and carbon number of the compounds. The qualitative and quantitative results presented herein offer a unique perspective into the detailed comparison of different ionization techniques corresponding to several hydrocarbon classes.<p><strong>For more information:</strong> <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/jms.4319" target="_blank">https://onlinelibrary.wiley.com/doi/abs/10.1002/jms.4319</a></p> What Is the Opposite of Pandora’s Box? Direct Analysis, Ambient Ionization, and a New Generation of Atmospheric Pressure Ion Sourceshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/what-is-the-opposite-of-pandoras-box-direct-analysis-ambient-ionization-and-a-new-generation-of-atmospheric-pressure-ion-sourcesMass Spectrometry (MS)Sat, 07 Mar 2020 15:53:10 GMTThe introduction of DART and DESI sources approximately seven years ago led to the development of a new series of atmospheric pressure ion sources referred to as “ambient ionization” sources. These fall into two major categories: spray techniques like DESI or plasma techniques like DART. The selectivity of “direct ionization,” meaning analysis without chromatography and with little or no sample preparation, depends on the mass spectrometer selectivity. Although high resolution and tandem mass spectrometry are valuable tools, rapid and simple sample preparation methods can improve the utility of ambient ionization methods. The concept of ambient ionization has led to the realization that there are many more ways to form ions than might be expected. An interesting example is the use of a flint-and-steel spark source to generate ions from compounds such as phenolphthalein and Gramicidin S.<p><strong>For more information:</strong> <a href="https://www.jstage.jst.go.jp/article/massspectrometry/2/Special_Issue/2_S0007/_article" target="_blank">https://www.jstage.jst.go.jp/article/massspectrometry/2/Special_Issue/2_S0007/_article</a></p> Rapid detection of fentanyl, fentanyl analogues, and opioids for on-site or laboratory based drug seizure screening using thermal desorption DART-MS and ion mobility spectrometryhttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/rapid-detection-of-fentanyl-fentanyl-analogues-and-opioids-for-on-site-or-laboratory-based-drug-seizure-screening-using-thermal-desorption-dart-ms-and-ion-Mass Spectrometry (MS)Sat, 07 Mar 2020 15:51:37 GMTFentanyl and fentanyl analogues represent a current and emerging threat in the United States as pure illicit narcotics and in mixtures with heroin. Because of their extreme potency, methods to safely and rapidly detect these compounds are of high interest. This work investigates the use of thermal desorption direct analysis in real time mass spectrometry (TD-DART-MS) and ion mobility spectrometry (IMS) as tools for the rapid and sensitive (nanogram to picograms) detection of fentanyl, 16 fentanyl analogues, and five additional opioids. Competitive ionization studies highlight that detection of these compounds in the presence of heroin is readily achievable, down to 0.1% fentanyl by mass with TD-DART-MS. With IMS, detection of nanogram levels of fentanyl in a binary fentanyl and heroin mixture is possible but can be complicated by decreased resolution in certain commercial instrument models. Modifications to the alarm windows can be used to ensure detection of fentanyl in binary mixtures. Additionally, three complex background matrices (fingerprint residue, dirt, and plasticizers) are shown to have a minimal effect of the detection of these compounds. Wipe sampling of the exterior of bags of questioned powders is shown to be a safe alternative method for field screening and identification, removing the need to handle potentially lethal amounts of material.<p><strong>For more information:</strong> <a href="https://www.sciencedirect.com/science/article/pii/S2468170917300152" target="_blank">https://www.sciencedirect.com/science/article/pii/S2468170917300152</a></p> Mechanosensitivity below Ground: Touch-Sensitive Smell-Producing Roots in the Shy Plant Mimosa pudicahttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/mechanosensitivity-below-ground-touch-sensitive-smell-producing-roots-in-the-shy-plant-mimosa-pudicaMass Spectrometry (MS)Sat, 07 Mar 2020 15:49:57 GMTThe roots of the shy plant Mimosa pudica emit a cocktail of small organic and inorganic sulfur compounds and reactive intermediates into the environment, including SO2, methanesulfinic acid, pyruvic acid, lactic acid, ethanesulfinic acid, propanesulfenic acid, 2-aminothiophenol, S-propyl propane 1-thiosulfinate, phenothiazine, and thioformaldehyde, an elusive and highly unstable compound that, to our knowledge, has never before been reported to be emitted by a plant. When soil around the roots is dislodged or when seedling roots are touched, an odor is detected. The perceived odor corresponds to the emission of higher amounts of propanesulfenic acid, 2-aminothiophenol, S-propyl propane 1-thiosulfinate, and phenothiazine. The mechanosensitivity response is selective. Whereas touching the roots with soil or human skin resulted in odor detection, agitating the roots with other materials such as glass did not induce a similar response. Light and electron microscopy studies of the roots revealed the presence of microscopic sac-like root protuberances. Elemental analysis of these projections by energy-dispersive x-ray spectroscopy revealed them to contain higher levels of K+ and Cl− compared with the surrounding tissue. Exposing the protuberances to stimuli that caused odor emission resulted in reductions in the levels of K+ and Cl− in the touched area. The mechanistic implications of the variety of sulfur compounds observed vis-à-vis the pathways for their formation are discussed.<p><strong>For more information:</strong> <a href="http://www.plantphysiol.org/content/170/2/1075" target="_blank">http://www.plantphysiol.org/content/170/2/1075</a></p> Identification of selected CITES-protected Araucariaceae using DART TOFMShttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/identification-of-selected-cites-protected-araucariaceae-using-dart-tofmsMass Spectrometry (MS)Sat, 07 Mar 2020 15:47:37 GMTDetermining the species source of logs and planks suspected of being Araucaria araucana (Molina) K.Koch (CITES Appendix I) using traditional wood anatomy has been difficult, because its anatomical features are not diagnostic. Additionally, anatomical studies of Araucaria angustifolia (Bertol.) Kuntze, Araucaria heterophylla (Salisb.) Franco, Agathis australis (D.Don) Lindl., and Wollemia nobilis W.G.Jones, K.D.Hill & J.M.Allen have reported that these taxa have similar and indistinguishable anatomical characters from A. araucana. Transnational shipments of illegal timber obscure their geographic provenance, and therefore identification using wood anatomy alone is insufficient in a criminal proceeding. In this study we examine the macroscopic appearance of selected members of the Araucariaceae and investigate whether analysis of heartwood chemotypes using Direct Analysis in Real Time (DART) Time-of-Flight Mass Spectrometry (TOFMS) is useful for making species determinations. DART TOFMS data were collected from 5 species (n =75 spectra). The spectra were analyzsed statistically using supervised and unsupervised classification algorithms. Results indicate that A. araucana can be distinguished from the look-alike taxa. Another statistical inference of the data suggests that Wollemia nobilis is more similar and within the same clade as Agathis australis. We conclude that DART TOFMS spectra can help in making species determination of the Araucariaceae even when the geographic provenance is unknown.<p><strong>For more information:</strong> <a href="https://brill.com/view/journals/iawa/38/2/article-p266_8.xml" target="_blank">https://brill.com/view/journals/iawa/38/2/article-p266_8.xml</a></p>