Tandem mass spectrometry Natural products

Natural products and natural-like compounds, generally coming from microbes, plants, sponges and animals [2, 3] may be fully identified and quantified by means of modem and advanced analytical techniques, such as high-performance liquid chromatography (HPLC) coupled to various detectors - from the most common UV/Vis to mass spectrometry and tandem mass spectrometry (HPLC-MS and HPLC-MS/MS). The role of MS is to provide quantitative and qualitative information about mixtures separated by liquid chromatography [4],... 

Sandvoss, M. Weltring, A. Preiss, A. Levsen, K. Wuensch, G. Combination of matrix solid-phase dispersion extraction and direct on-line chromatography-nuclear magnetic resonance spectroscopy-tandem mass spectrometry as a new efficient approach for the rapid screening of natural products Application to the total asterosaponin fraction of the starfish Asterias rubens. J. Chromatogr., A 2001, 917, 75-86. 

Improvements in the instrumentation, ionization sources, high-resolution mass analyzers, and detectors [67-69], in recent years have taken mass spectrometry to a different level of HPLC-MS for natural product analysis. Mass spectrometry detection offers excellent sensitivity and selectivity, combined with the ability to elucidate or confirm chemical structures of flavonoids [70-72]. Both atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) are most commonly used as ionization sources for flavonoid detection [73-76]. Both negative and positive ionization sources are applied. These sources do not produce many fragments, and the subsequent collision-induced dissociation energy can be applied to detect more fragments. Tandem mass spectrometry (MS , n> 2) provides information about the relationship of parent and daughter ions, which enables the confirmation of proposed reaction pathways for firagment ions and is key to identify types of flavonoids (e.g., flavones, flavonols, flavanones, or chalcones) [77-80]. 

Pachuta RR, Kenttamaa HI, Cooks RG, Zennie TM, Ping C, Chang C-J, Cassady JM. Analysis of natural products by tandem mass spectrometry employing reactive collisions with ethyl vinyl ether. Org Mass Speetrom. 1988 23 10-15. 

Alternatively, the primary ions may be scanned with the second mass analyzer held constant to produce a parent spectrum. This type of tandem mass spectrometry reveals all the reactant ions giving rise to a particular fragment ion. Kon-drat et al. (215) have demonstrated applications of this technique to the identification of biosynthetically related natural products that fragment to a common ion. 

Quirke, J. M. E. Hsu, Y.-L. Van Berkel, G. J. Ferrocene-based electroactive derivatizing reagents for the rapid selective screening of alcohols and phenols in natural product mixtures using electrospray tandem mass spectrometry. J. Nat. Prod. 2000, 63, 230-237. 

Julian, R.K. Jr. Tandem Mass SpecTomelry in Natural Products Discovery, in Proceedings of the 44th ASMS Conference on Mass Spectrometry and Allied Topics, Portland, Oregon, May 12-16, 1996. 

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