Contamination, Peak at m/z 100

[Alp]

I am curious about a peak I am seeing at m/z 100, ionspray, positive ion mode on an API-III.

I looked at a table I found on common background ions to see if I could find a good candidate. I could not.

The front end, orifice, behind curtain plate, Q0 through to end of Q1 were recently cleaned to remove high background signal. The background improved significantly but I was left with a huge peak at m/z 100.

I was infusing 75/25 methanol /0.1% formic acid in type one water at the time I noticed the peak. The peak remained when I switched to ACN/0.1% formic acid in type one water. The intensity is in the millions. It is BIG.

I am curious what it could be coming from. I suspect one of the solvents used to clean with, the plastic containers I used for holding the solvents (polypropylene) or the latex gloves.


Any ideas?


Alp

[Pepter]

DMSO ?

[bhuvfe]

http://en.wikipedia.org/wiki/Methylpyrrolidone ?

[Alp]

Yes, Methylpyrrolidone seems a reasonable candidate.

Sodium+ adduct of DMSO would show up at 101.

Thanks

[cloudyarun]

i have a problem in ms. very low intensity problem.i cleaned glass capillary and spary shield with ACN. still intensity is not raised..
i am using Bruker daltonics Mass spectrometry