Performance Characteristics of a Comprehensive GCxGC-High Resolution TOFMS System Utilizing Chemical Ionization
Poster May 22, 2015
Jonelle Shiel, Mark Merrick, Scott Pugh, Matthew Soyk, and Viatcheslav Artaev
Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful tool which leads to dramatically improved separation for complex samples. This technique generates very narrow chromatographic peaks, requiring a high speed detection system to accurately represent the chromatographic separation in two-dimensional space. When combined with a rapid acquisition High Resolution Time-of-Flight Mass Spectrometer (HRTOFMS), the resulting accurate mass data provides additional information for compound identification.
A soft ionization source, which generates mostly molecular or quasi molecular ions, further enhances the information available by allowing for the unambiguous, or nearly unambiguous, identification of the elemental composition of compounds of interest. Conventional Electron Ionization (EI) sources used for MS detection systems generate multiple fragment ions and can limit the formation of the parent ion of interest. Incorporating Chemical Ionization (CI) can greatly assist in maintaining the molecular or quasi molecular ion relative to the typically used EI source. This work demonstrates the performance of a GC×GC-HRTOFMS with a CI source.
The LECO Pegasus® GC-HRT 4D supports standard CI reagent gases, including methane, isobutane, and ammonia, while also allowing for custom gases to be chosen. To assist in optimization of the ion source, both automated and manual reagent gas flow optimizations are available. In addition, the instrument allows for simple exchange of the ion source between CI and EI.
The data presented includes: Benzophenone standards to demonstrate the instrument’s performance regarding detection limit, linear dynamic range, precision, resolution, and mass accuracy. A 10% Diesel sample is also included to demonstrate the two-dimensional separation capability of the instrument.
Using Elemental Analysis For Discrimination Of Pinot Noir Wines From Six Different Districts In An AvaPoster
The determination of geographical origin of wine is gaining increased interest by researchers and federal agencies around the world, partially due to increased fraud with regards to place of origin labelling. For wine, multi-elemental profiling of macro, micro, and trace elements has been proposed for determination of authenticity. Commercial wines from different wineries in 5 different neighborhoods within one AVA show characteristic elemental fingerprints. Macro, micro and trace elements as well as elemental ratios contribute to the observed separation, indicating the involvement of multiple factors and underlying mechanisms, including location and soil composition, elemental uptake by vine and rootstock, viticulture and nutrient management, water sources, and small differences in the different wineries.READ MORE
Fast arsenic speciation analysis of wines and rice with LC-ICP-QQQPoster
This method was designed in response to recent and proposed food standards, both international and national, that limit inorganic arsenic rather than total, organic, or individual arsenic species such as arsenite (AsIII) and arsenate (AsV). Analysis time is 10x faster than the current FDA regulatory method, increasing sample throughput, avoided spectral interferences and dramatically increased sensitivity. Validation data from two laboratories demonstrate the method’s accuracy and reproducibility of both wine and rice matrices in a single analytical batch.READ MORE
Proteomics and Substrate Based MS Imaging of Xenobiotic Metabolising Enzymes in Ex Vivo Human Skin and a Human Living Skin Equivalent ModelPoster
Untargeted proteomics analysis showed that human skin and a commercially available living skin equivalent model exhibit a similar distribution of xenobiotic metabolising enzymes. A new technique, substrate based mass spectrometry imaging (SB-MSI) was developed during this study.READ MORE