Dear Dr. Ntsoelinyane,

Start with trying to answer the following:

1. What plant species was studied?

2. What plant part of the species studied?

3. List all the compounds isolated/identified in the plant (part)species along with each compounds UV spectral characters (eg. lambda max) and molecular weight

4. define the class to which each listed compound

5. What is the solvent of extraction of the plant species : - This would broadly give you to figure out what kind of compounds are extracted - For eg. If you had used methanol, all moderately to highly polar compounds would have extracted.

7. From your list figure out the ones that are soluble in methonol to give you some indication of what type of compounds are present in your sample matrix.

8. What type of system was used: Hopefully you used HPLC- UV Detector- ESI MS detector in a sequence. If you have done that then

9. List each peak detail: UV spectrum (if it was a PDA detector) otherwise check there is a peak in the detected wavelength and whether you see a corresponding peak in the TIC (Total ion chromatogram) in MS. If a peak is present in both detection at the same time, then you have a compound which is UV absorbing and amenable to 'ionisation'

10. List the UV absorption max and the molecular ion (if you have used +mode in MS, the molecular weight + 1 is what you get; if you have used -mode in MS, the molecular weight - 1 is what you get).

11. compare your listed data with the data listed from literature reported compounds that you initially listed.

This is a very general way to go around. If you are lucky, you will be able to 'tentatively' identify some constituents.

Atleast this exercise will give you what to look for.

Please also remember:

In ESI-MS negative or positive mode, if you hare having organic compounds (containing only Carbon, hydrogen and oxygen) you will get 'even' number of 'molecular ion' (M+1 or M-1). This is because the organic compounds will have 'odd' number molecular weight.

If your compound(s) are alkaloids with one Nitrogen, then you will get 'odd' molecular weight numbers in MS (either + or - 1 of molecular weight) since alkaloids with one nitrogen in the molecule have 'odd' number of molecular weight.

This is a rough way (and not a precise one) to go about. But it gives some idea to start with.

Good Luck

Dear Dr. Ntsoelinyane,

Start with trying to answer the following:

1. What plant species was studied?

2. What plant part of the species studied?

3. List all the compounds isolated/identified in the plant (part)species along with each compounds UV spectral characters (eg. lambda max) and molecular weight

4. define the class to which each listed compound

5. What is the solvent of extraction of the plant species : - This would broadly give you to figure out what kind of compounds are extracted - For eg. If you had used methanol, all moderately to highly polar compounds would have extracted.

7. From your list figure out the ones that are soluble in methonol to give you some indication of what type of compounds are present in your sample matrix.

8. What type of system was used: Hopefully you used HPLC- UV Detector- ESI MS detector in a sequence. If you have done that then

9. List each peak detail: UV spectrum (if it was a PDA detector) otherwise check there is a peak in the detected wavelength and whether you see a corresponding peak in the TIC (Total ion chromatogram) in MS. If a peak is present in both detection at the same time, then you have a compound which is UV absorbing and amenable to 'ionisation'

10. List the UV absorption max and the molecular ion (if you have used +mode in MS, the molecular weight + 1 is what you get; if you have used -mode in MS, the molecular weight - 1 is what you get).

11. compare your listed data with the data listed from literature reported compounds that you initially listed.

This is a very general way to go around. If you are lucky, you will be able to 'tentatively' identify some constituents.

Atleast this exercise will give you what to look for.

Please also remember:

In ESI-MS negative or positive mode, if you hare having organic compounds (containing only Carbon, hydrogen and oxygen) you will get 'even' number of 'molecular ion' (M+1 or M-1). This is because the organic compounds will have 'odd' number molecular weight.

If your compound(s) are alkaloids with one Nitrogen, then you will get 'odd' molecular weight numbers in MS (either + or - 1 of molecular weight) since alkaloids with one nitrogen in the molecule have 'odd' number of molecular weight.

This is a rough way (and not a precise one) to go about. But it gives some idea to start with.

Good Luck

Dr. Govindaraghavan is rigth (except that neutral molecule with no or even nitrogen content have even moleculare weight). But in general it's a great work that of to correlate HPLC-MS spectra with the molecules in the sample. You need to collect all possible information and made educated guess. Unless you can count on high resolution masses (from whict you can directly have the molecular formula) or mass from electronic impact (that give several fragments that you can check on databases like those of NIST).

HPLC-MS is likely not going to cut it since a lot of plant metabolites are isobaric. Your best bet would be to acquire LC/MS/MS e.g. on a QTOF instrument, and then use the combination of accurate precursor mass and MS/MS fragmentation to search against a publicly available database, e.g. Metlin.