Can LCMS help to verify the presence of different phytochemical constitutes in the plant extract? Because their may be many phytochemical compounds present in the plant extract, can we verify most of them with the help of LCMS data?
Yes, it is possible when you have percent peak area. in LC chromatogram, each peak respect to the single compound, at the same time the area and length of peak occupancy determines the concentration of compound. If you got highest peak with increased width, it indicates the rich component in the extract.
hope this helps you.
Yes, LCMS identify the present phytochemical compounds in the plant extract. After identifying the present components, LCMS-QTOF can as well be used for validating the identified components or you can use standards for targeted components to be rest assure.
I hope this is helpful.
Often it is not possible to completely characterize all the compounds. For example, if you have a glycoside you can only identify the class of te compound, i.e. flavonoids, saponins, etc. You cannot be sure of the position of linkage(s) between aglycon and sugar(s). Furthermore you cannot identify the exact sugar(s), but only if they are hexoses, pentoses, deoxysugars, etc. Finally, you cannot establish how the sugars are connected each other
Dear Ravi
LCMS can help in the identification of a lot of class of compounds present in plant extract. But in case you have a glucoside compound or a new compound, this technic will be limited. you will just detect the presence of the compound in the LC chromatogram but you couldn't be able to identify it.
Dear Rajesh.
In short it all depends on what you are looking for and whether you have existing standards or knowledge of the type of molecules you are looking for.
You mention LCMS as a possible method for phytochemical identification and I am not sure if you are referring to LC-MS or LC-MS/MS as these are both mass spectrometry based techniques with quite different abilities and often confused by inexperienced users.
The advantage of both techniques is you can determine the mass of the precursor ion (the mass of the molecules that are separated chromatographically and elute at specific retention times) and if you have a standard or good knowledge of the compounds expected to elute at the retention time, you would be able to allocate a possible identity. As mentioned previously in these replies the fact that different isomeric forms (in terms of conjugated carbohydrate or even different isomeric forms such as with the polyphenolics and flavanoid compounds) could be present and mass spectrometers cannot give structural information for these individual compounds. There are no structural libraries available for LC-MS/MS, as is the case for GC-MS where high energy electron impact ionisation in the gas phase ensures consistent fragmentation, but you can build your own libraries using a consistent method which can then be used later to help identify the individual compounds.
Using LC-MS does not give any true compound identity as these instruments are nominal mass instruments which cannot predict the empirical formulae for the different compounds, but can be used to confirm the possible structures in combination with the retention time and chromatographic conditions.
On the other hand using accurate mass systems that are normally configured as LC-MS/MS type instruments much more information can be obtained through controlled fragmentation of the precursor to give different confirmatory fragements that could easily confirm the presence of single or multiple sugar moeities. Again due to the possibility of many isomeric compounds with the same exact mass you cannot give a positive identity without supporting information.
One point to keep in mind is that the initial plant extraction technique will have a strong influence on the class of compound that is being extracted. For example alkaloids have a specific extraction and cleanup technique while lipids and sugars have different extraction methods due to their solvent solubilities. When assaying polyphenols there are many possibilities and these as well as the flavanoid compounds have many isomeric compounds that would have the same mass, requiring at least some standards to be able to make sense of the elution order.
Perhaps you should read up on targeted versus un-targeted mass spectrometric analysis, which could give you some further background. There are many good textbooks and marketing literature available. This would give you a clearer idea of what is possible.
If you have the compounds already extracted and the sub-fractions are relatively pure you could also attempt NMR to give supporting structural data.
Good luck
Hi,
Can I get a fingerprint of the plant extract on LC / MS / MS (3Q) or HPLC? Does it make any sense if we don't use substance standard?
Reviewers asked me to better characterize the extract used in cell research. They recommended LC / MS. I have little time to answer and I won't be able to buy any more standards.
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