GC-MS – Multimedia

Despite all the progress in the proteomic and genomic research, the quantitation of steroids in biological samples is still needed for the establishment of the biochemical phenotype of disorders affecting steroid biosynthesis.

Examples will be highlighted for food/flavor/fragrance, metabolomic, and petrochemical application markets. The advantage in number of compounds detected and overall quality of their mass spectral library similarity scores, as compared to one-dimensional methods will be clearly demonstrated.

The aim of this work was non-targeted screening of xenobiotics in paper and paperboard packaging materials used for food packaging in the Czech Republic.

A new dual-layer cartridge for the efficient extraction of PAHs from edible oils

A GC/MS or LC/MS workflow for Metabolomics applications includes a number of distinct steps: experimental design, sampling, sample preparation, data acquisition, data processing, deconvolution, identification and data interpretation.

The MsXelerator software includes Quality Control procedures and Analysis of Variance (ANOVA) to properly control each step in this workflow and to obtain reliable results for both quantitation and identification.

A sharp, narrow, and sensitive peak is a pre-condition for a sensitive GC analysis. Therefore, a protectant is needed to protect the analyte from any type of distortion for integration and to prevent overestimation. Existing solutions do not overcome these problems completely due to limitations. As the matrix enhancement problem originated from matrix components, its solution should come from similar components.

Acetonitrile was used as the extraction solvent with sodium chloride to enhance the partitioning of analytes into the organic phase. Recovery indicated good method accuracy and repeatability, and was within the acceptable range for residue determinations. The mere presence of pesticide residues in tea does not necessarily mean that the tea has become toxic and would pose a health hazard. We revealed that only a negligible or small percentage of pesticides in tea is transferred to the infusion.

The dSPE of QuEChERS was replaced with an SPE cartridge, which provided a very clean chromatogram, although a small recovery percentage was obtained. The method fulfilled all validation criteria and was useful for monitoring etoxazole residues in red pepper. It can also be used and optimized for other fruit and vegetable matrices.

QuEChERS involves an initial step when a few grams of the sample are extracted with acetonitrile followed by a clean-up step (with dispersive-SPE) used to remove, to a certain extent, unwanted matrix compound (such as pigments, sugars, organic acids). With QuEChERS, the final extract ends up with the pesticides in acetonitrile, which, being polar solvent, can be
problematic in GC-MS.

Analysis of Herbal powders or ‘churnas’ using an optimized GC-MS/MS method is described. As they have high amount of matrix co-extractives, they pose critical analytical problems. The purpose of this work was overcome the effect of the matrix and develop a reliable method.