[adhikary]

Hello Scholars,
I’m doing work on Organophophorus compounds. One of my compounds is containing pyridine and it is ionic. Pyridine containing phosphate part is positively charged and the anion is chloride. I need to check its Mass. I tried with GC-MS and LC-MS in Acetonitrile, but couldn’t find the mass. Do you think it is possible to detect mass by chromatography? I test TLC with different composition of ethyl acetate / n-Hexane, Acetonitrile/n-Hexane, Acetonitrile/diethylether etc. but the expected product spot doesn’t move from the base. Do you have any suggestion?

[Honclbrif]

You can't determine the molar mass of a small molecule by chromatography, and you can't to GC-MS on ionic compounds (salts are largely nonvolatile).

LC-MS should have worked just fine in positive ion mode. Just a few questions then:
1. Did you flush your compound out before you started acquiring data?
2. Is your sample concentrated enough?
3. Is your sample free of salts, detergents, and particulates?
4. Is your sample soluble in ACN?

[orgopete]

You should be able to see your compound with LC-MS. I am presuming water is the other phase with acetonitrile. You can dissolve your sample in water or methanol if needed, especially if all you are seeking is the MW of the chemical ionization. It may be an adduct of an ion modifier (if used).

[adhikary]

Honclbrif and Orgopete,

Thank you for discussions.

The answer of your all queries are yes! infact I flushed the whole mass with petrolium ether. Infact I performed the reaction in ACN (Acetonitrile). I need to separate the product, but I lost the product with several attempts. I expect the product as [(RO)P(=O)(OPh)(NC₅H₅)]⁺Cl^-, here R = Ethyl and Methyl groups. If you have any more ideas will be accepted with a coordial thank.