Analytical challenge for determination of instable standard of other N-nitroso structure

[daniel.silveira]

Hello Figo,

The theme for nitroso-tadafil is already be discussed in another topic.

N Nitroso Tadalfil

Hello all, I am developing an LC–MS/MS method for N-nitroso tadalafil. Based on structure, I expected the [M+H]⁺ precursor around m/z 419, but in my scan I am seeing a strong signal at m/z 389. Has anyone else observed m/z 389 for N-nitroso tadalafil? Is this a valid precursor ion or could it be an in-source fragment/adduct? Any insights or shared experience would be very helpful.

However one of the main problems is the standard stability. At low temperatures is quite stable in solid and solution form. When we developed the method the standard and samples should be prepared at low temperature (as possible) and avoid light as much as possible. Only with this conditions we were able to get some results for Nitroso-Tadalafil.

Best Regards,

Daniel