Specificity analysis HRMS

Eljarrat E and Barcelo D (2002) Congener specific analysis of dioxins and related compounds by gas chromatography coupled to LRMS, HRMS, MS-MS and TOF-MS. Journal of Mass Spectrometry 37 1105-1117. 

Finally, a third method has been proposed for the analysis of toxaphene using EI-HRMS in SIM mode [98,99], This method is based on the congener-specific analysis for Parlar No. 26, 50, and 62, which are considered as indicators of toxaphene contamination. Selective ion monitoring at a resolving power of 10,000 of mass fragments at m/z 340.8806 ([M — Cl — HCl] cluster ion) for Parlar No. 26 and at m/z 338.8649 and 340.8620 ([M — Cl — 2HC1] cluster... 

Future development in GC-MS analysis will require the use of more stable GC capillary columns or multidimensional GG coupled to advanced MS techniques such as HRMS and MS-MS with El and EGNI ionization. The availability of further individual congeners for specific analysis and isotopically labeled standards will assure an accurate quantitative analysis. In addition, the development of more selective analytical methods for the isolation of these compounds from environmental and biological matrices can help to enhance the selectivity of the LRMS techniques. Further research and collaborative studies still need to be done to solve the problems associated with the analysis of PGTs and toxaphene. 

Direct solid-state polymer/additive mass analysis has involved various ionisation modes El (Section 6.2.1), Cl (Section 6.2.2), DCI (Section 6.2.2.1), FAB (Section 6.2.4), FI (Section 6.2.5), FD (Section 6.2.6) and LD. Survey mass spectra obtained with soft ionisation methods (FI-MS, CI-MS) provide diagnostic overviews of chemical composition. The supplemental tandem (MS/MS) and atomic composition (AC-MS) techniques are used to make specific identifications of various organic ingredients. Direct analysis of polymer systems for more than a few thousand daltons has only just begun. Ionisation methods employed are FD, ESI and MALDI. Solid-probe ToF-MS (or DI-HRMS) is a breakthrough [188]. 

Quantitative Bioanalysis with High Mass Resolution Prior to the introduction of the API sources for LC-MS, GC-MS was the dominant format for mass spectrometry. Within GC-MS, mass analysis at high resolution using magnetic sector instruments was relatively common, especially in the central mass spectrometry facilities of major corporations and universities. Uses of these instruments included quantitation by GC-HRMS for improved specificity and sensitivity. 

Two recent papers examining coal extracts showed little evidence for multiple heteroatom species in the small molecules (1-2Y The extracts of an abnormally high sulfur coal from Yugoslavia were found to contain species with several sulfurs per molecule (3). HRMS analysis of extracts from the Argonne Premium Coal Sample used in this study showed evidence for species containing both SO and SN (4-5 Y Specific compounds containing sulfur and... 

Figure 40. Comparison of analysis of standard solutions containing 200 pg of TCDD and 200 ng of Arachlor 1260 using (a) both the GC/HRMS and DP/SRM (direct probe/specific reaction monitoring) for (b) this mixture and (c) a sample containing only 200 ng of TCDD [193].

In general, ECNI-HRMS can provide higher sensitivity, whereas higher selectivity can be achieved using the EI-HRMS mode. This can be explained by the broad fragmentation pattern obtained with El, which allows one to chose a more specific ion to be monitored. Thus, both HRMS techniques may offer greater possibilities than LRMS for the analysis of toxaphene. 

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