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Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: kamiyu on August 07, 2014, 04:47:30 PM

Title: About reporting of Mass spec rsult involving bromine atom
Post by: kamiyu on August 07, 2014, 04:47:30 PM

Not sure if I should place a topic here but i am writing my paper and I am stuck with reporting one of my compound that has a bromine on it.

The m/z peaks are 245 and 247, clearly suggesting the presence of bromine and this is correct.

But how about reporting these number ??

Shoudl I say the molecular ion is 245? or 247??? or I should report both?? If so, HOW???

Thanks

Title: Re: About reporting of Mass spec rsult involving bromine atom
Post by: rwiew on August 07, 2014, 06:30:30 PM

You're writing a journal paper? Will depend on the style of the journal of course, see past articles.

Title: Re: About reporting of Mass spec rsult involving bromine atom
Post by: clarkstill on August 08, 2014, 03:33:40 AM

I was always taught that you give the lowest mass molecular ion, since all the higher peaks are contaminated by the 1% carbon-13, or by any deuterium that might have found its way in from an NMR solvent etc., but if in doubt just give both.

Title: Re: About reporting of Mass spec rsult involving bromine atom
Post by: MOTOBALL on August 08, 2014, 10:17:00 AM

A common way of handling this is,

"The [M+H]⁺ ion was observed as an approximately 1:1 doublet at m/z 245, 247 which is consistent with the presence of a single Br atom."

Have you resolved the issue of M +16 and +28 m/z signals that you had mentioned in an earlier post ??

Title: Re: About reporting of Mass spec rsult involving bromine atom
Post by: kamiyu on August 08, 2014, 10:54:35 AM

Thanks for your reply

M+16 is oxidized molecular ion because the method is ASAP

There is nothing that increases molecular ion by 28. The M+28 that I have is 391m/z which is the plasticizer. (diooctyl phthlate)