The application of mass spectrometric techniques for the analysis of the complex mix‐ tures inherent in fuel and lubricant samples will be examined. These samples because they are naturally complex mixtures, typically requires either very high resolution mass spectrometry or one of the hyphenated techniques gas chromatography‐mass spectrometry(GC‐MS) or liquid chromatography‐mass spectrometry (...

Fast and reliable analytical methods for mercury speciation would aid in understanding mercury offgas chemistry. Presently, the U.S. Environmental Protection Agency (EPA) regulates only total mercury; however, many studies indicate that mercury toxicity is highly dependent on the mercury speciation. For example, amalgams and mercury sulfides have relatively low toxicities, while organomercury a...

Body fluid proteome is the most informative proteome from a medical viewpoint. But the lack of accurate quantitation method for complicated body fluid limited its application in disease research and biomarker discovery. To address this problem, we introduced a novel strategy, in which SILAC-labeled mouse serum was used as internal standard for human serum and urine proteome analysis. The SILAC-...

Summary Stable isotope directed metabolomics is increasingly being used to measure metabolic fluxes in microbial, plant and animal cells. Incorporation of 13C/15N isotopes into a wide range of metabolites is typically determined using gas chromatography-mass spectrometry (GC/MS) or other hyphenated mass spectrometry approaches. The DExSI pipeline is an interactive graphical software package whi...

In this study, a QuEChERS method and gas chromatography coupled with time-of-flight mass spectrometry (GC×GCTOFMS) was developed for rapid extraction and simultaneous determination of 12 pesticide residues in honey. The GC×GC-TOFMS method was validated according to the SANCO guidance in terms of linearity, selectivity, reproducibility and recovery. Regarding the results, recovery rates ranged b...

The Critical Assessment of Small Molecule Identification, or CASMI, contest was founded in 2012 to provide scientists with a common open dataset to evaluate their identification methods. In this article, the challenges and solutions for the inaugural CASMI 2012 are presented. The contest was split into four categories corresponding with tasks to determine molecular formula and molecular structu...

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used ...

Because of the growing number analysis scenarios involving complex samples, comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC–TOF-MS) is now a prominent technique for characterization. However, limitations on time, expenses, and sample quantities, as well need specialized expertise in comparative analysis, can prevent discovery analytes that d...

A quantitative analysis of the individual compounds in tobacco essential oils is performed by comprehensive two-dimensional gas chromatography (GC x GC) combined with flame ionization detector (FID). A time-of-flight mass spectrometer (TOF/MS) was coupled to GC x GC for the identification of the resolved peaks. The response of a flame ionization detector to different compound classes was calibr...

the present study describes the fragmentation under electron ionization (ei) of gas phase serine and threonine amino acids. ab initio methods were performed to calculate the fragmentation paths and interpret the mass spectra. the six lowest energy conformers of l-serine, l-threonine and l-allo-threonine were obtained with b3lyp, g3mp2 and mp2 methods. the adiabatic and vertical ionization energ...