Related Articles

• 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 spectrometry

  Fentanyl 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.
• Simultaneous determination of residual agricultural chemicals in food by GC-MS/MS - MSTips259

  As "food safety" is recognized as an increasingly important issue on a global scale, many nations have their own regulations on residual agricultural chemicals in food. In Japan, the positive list system, which was enforced at the end of May 2006, stipulates a uniform standard of 10 ppb as a quantity that is considered safe for human health. Under the positive list system, more agricultural chemicals need to be examined, and as a result, techniques capable of accurately and collectively analyzing residual agricultural chemicals in food are in increasing demand. While mass spectrometry (MS) is known for its high detection sensitivity, MS/MS is becoming the mainstream of pesticide analysis for its superior sensitivity and selectivity. The JMS-TQ4000GC, JEOL’s latest GC-MS/MS system, has a unique ion storage/ejection mechanism within the MS/MS collision cell and incorporates new firmware to support MS/MS analysis with up to 36,000 transitions. In this work, we report the verified results for pesticide residues sensitivity in food using the JMS-TQ4000GC.
• Study of Chemical Exchange by 2D NMR

  The NMR signal of a spin reflects its local magnetic environment. If a spin due to chemical exchange samples two magnetically different states then its NMR signal would reflect both states. Its appearance on a NMR spectrum would be determined by the dynamics of the exchange event. In the case of chemical exchange that is slow on the NMR time scale, it is possible to observe two distinct signals for the same spin, one signal for each state under exchange. Presence of chemical exchange is often demonstrated with the exchange experiment (2D NOESY experiment). A exchange peak (cross peak) of the same sign can be observed between the two autopeaks (diagonal peaks) that represent the two states under exchange. Because the same results can be interpreted in a different way based on NOE, further evidence is desirable.
• Instantaneous Detection of Explosives on Clothing

  The detection of explosives is of vital importance in forensic applications and in preventing criminal or terrorist activity. The analytical detection of explosives on surfaces is normally done by using solvent extractions or wipes and chromatography or chromatography combined with mass spectrometry. This is inefficient because solvent extractions and wipes only result in a partial transfer of material from the surface into the sampling material. Furthermore, the chromatographic analysis can be time-consuming and requires the use of disposable solvents (an environmental concern). The JEOL AccuTOF™ with Direct Analysis in Real Time (DART™) has demonstrated the capability to detect both volatile and involatile explosives on surfaces such as plastic, cloth, concrete, glass, cardboard, metal, and more. No wipes or solvent extractions are required. The method is instantaneous, environmentally friendly, and does not require solvents. An example is shown in this application note.
• Stability in quantitative analysis of residual agricultural chemicals in food by GC-MS/MS - MSTips262

  As "food safety" is recognized as an increasingly important issue on a global scale, many nations have their own regulations on residual agricultural chemicals in food. In Japan, the positive list system, which was enforced at the end of May 2006, stipulates a uniform standard of 10 ppb as a quantity that is considered safe for human health. Under the positive list system, more agricultural chemicals need to be examined, and as a result, techniques capable of accurately and collectively analyzing residual agricultural chemicals in food are in increasing demand. While mass spectrometry (MS) is known for its high detection sensitivity, MS/MS is becoming the mainstream of pesticide analysis for its superior sensitivity and selectivity. The JMS-TQ4000GC, JEOL’s latest GC-MS/MS, has a unique ion storage/ejection mechanism within the MS/MS collision cell and incorporates new firmware to support MS/MS analysis with up to 36,000 transitions. In this work, we report the stability of 8 pesticides that were added to spinach extract.
• Molecular Characterization of Volatiles and Petrochemical Base Oils by Photo-Ionization GC×GC-TOF-MS

  The 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.