2015 Fiscal Year Research-status Report
化合物同定及び異性体識別に資する閾値エネルギー分解IMS/MS/MS法の開発
| Project/Area Number |
25513011
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
中村 健道 国立研究開発法人理化学研究所, 環境資源科学研究センター, 専任研究員 (10360611)
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| Project Period (FY) |
2013-04-01 – 2017-03-31
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| Keywords | tandem mass spectrometry / collision energy / CID MS/MS / isomer / diastereomer / energy-resolved MS/MS / fragmentation / ion mobility |
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| Outline of Annual Research Achievements |
We've integrated energy-resolved tandem mass spectrometry (ER MS/MS) capabilities to the ion mobility (IMS) MS/MS acquisition workflow in an LC/MS time-scale. The integration has enabled us acquisition of LC/ER MS/MS datasets in a high-throughput manner. In the meantime, the ER MS/MS datasets could be linked with IMS data for obtaining structural information on fragment ions of interests. We study the way to identify small molecules by using the information obtained through the integrated approach. Although combined use of molecular masses and retention indices is current standard procedure of isomer differentiation with LC/MS technology, opportunity to acquire MS data without chromatography will surely increase with the advancements in various in-situ ionization techniques. To cope with the future "no-chromatography" situations, we explored a strategy for isomer differentiation solely based on collision-induced dissociation (CID) MS/MS data. In general, isomer differentiation based on spectral matching fails as isomers often share substructures and/or common structural features that would give same fragment ions. On the other hand, each fragmentation channel has structure-dependent characteristics including critical (threshold) energy for each reaction pathway. Consequently, breakdown curves associated to each channel would become characteristic to each isomer. Experiments with some test samples including common isomeric metabolites showed that our ER MS/MS approach is useful for differentiation of isomers including diastereomers.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
In addition to the institutional reorganization that resulted in change of academic unit to which PI belongs, a fellow stuff scientist who had been sharing institutional tasks with PI had left the institution in the middle of fiscal year 2015. As a result of the confusion, PI had been fully occupied with institutional tasks temporarily and some inevitable delays occurred in the progress of research. Boy now, however, the situation had become under control and the goal of current project shall be accomplished by the end of fiscal year 2016.
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| Strategy for Future Research Activity |
Now the experimental workflow has been established, we continue to compile datasets for standard small organic compounds including common metabolites for a small database. Although data processing is still a bottleneck of current workflow, the issue has partly resolved by implementation of macros in the processing software. In parallel to the data compilation, we shall continue the software development by our own and also seek collaborations with the instrument manufacturer. For the future cross platform use of ER MS/MS datasets, the strategy for standardizing "representative pattern" associated to each isomer will be investigated.
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| Causes of Carryover |
In addition to the institutional reorganization that resulted in change of academic unit to which PI belongs, a fellow stuff scientist who had been sharing institutional tasks with PI had left the institution in the middle of fiscal year 2015. As a result of the confusion, PI had been fully occupied with institutional tasks temporarily and some inevitable delays occurred in the progress of research. Boy now, however, the situation had become under control and the goal of current project shall be accomplished by the end of fiscal year 2016.
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| Expenditure Plan for Carryover Budget |
To catch up and accomplish the goal by the end of fiscal year 2016, we continue to hire a part time worker to carry out some of the experimental work. Additional demands in supplies including consumables, chemicals, and travel expenses for attending pertinent conferences to present arrange shall also be covered by the carryover fund forwarded from the fiscal year of 2015.
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