Your question is rather vague - can you supply some more detail please? What is the nature of the sample? How is it being presented to the mass spectrometer - GC/MS, LC/MS? What information do you require?

Because HR-MS contemplates isotopic quantities. This feature is one of the characteristics of High Resolution.

Regard

Mr. Hyder,

Chan you provide chemometric data about the accuracy towards a standard?

Thanks Hocart. That was done by GC-MS (EI). My synthesised organic compound gave pure carbon and proton nmr data. But I did not get the accurate mass with Jeol USA high resolution mass.

The electron impact is a "hard" type ionization, i.e. you obtain strong fragmentation. The presence and abundance of molecular ion depends on the nature of compound.

regards,

G

As mentioned above, EI is an energetic form of ionisation and may not provide a molecular ion ( M+.). Can you tell us something more about the molecule you are analysing? How were you presenting it to the MS - by GC or by solids probe. Is it volatile? Is it thermally stable? Did you derivatise it?

Perhaps you could analyse it by LC- high resolution accurate mass MS using electrospray ionisation and look for a protonated adduct ([MH]+).

Thank you Mr. Charles Hocart. That was the derivatives of cyclic dithiocarbonate and ethanolamine. The solid sample was dissolved in acetone and injected for mass spectrometry

Mohammad,

regarding the intensity of molecular ions. - a chemical ionisation for GC-MS gives very nice spectra (the molecules are less fragmented).

regards,

G