We are very new at LC/MS and LC/MS/MS, AND we are really short on funds, so I am hoping someone can help me save time and money! We have a method for analysis of phthalate monoesters that was developed on a Finnigan TSQ triple quad. We are trying to set up the method on a Varian 1200L triple quad. We are using standard solutions of 500ng/ml, and still can't see the molecular ions or breakdown products we are supposed to see. BUT I do see a lot of m/z 91.5, 77.5 and 59.9. Am I missing a very basic common method of contamination? We have a nitrogen generator, with no hydrocarbon filter--could it be hydrocarbons? They are the same whether I inject in methanol or acetonitrile. Are there any good references about contamination in LC/MS(/MS)? Or could the problem be somewhere in the optimization? I'm a little lost, and would love some direction!
Thanks!