By cbyeoh on Wednesday, June 16, 2004 - 08:58 pm:

Hi all,

I am currently in the planning to develop the method for the analysis of PCBs with the LC/MS/MS. Is anyone of you have any literature or information about the analysis of PCBs with LC/MS/MS. I try to look for it from the internet and library, but I cant find one that discuss about this analysis. Most of the paper I read was related to the analysis of PCBs with HRGCMS, we don't have HRGCMS in our lab...Thanks

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By Anonymous on Thursday, June 17, 2004 - 07:36 am:

People use GCMS for PCBs because highly aromatic compounds do not work well by LCMS. You will probably have to derivatize in order to see anything. Have you thought about UV or fluorescence detection instead of MS?

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By MG on Friday, June 18, 2004 - 06:32 am:

It isn't the presence of aromatic rings that prevents compounds from working well in LC/MS, but the lack of protonation or deprotonation sites. But Anonymous is correct that these compounds would probably not work well via the traditional LC/MS ionization methods (ESI or APCI). I did a quick search and couldn't find anything. They would probably be good candidates for photoionization (APPI), but that ion source doesn't ship standard with LC/MS instruments at this time (we don't have one, yet).

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By cbyeoh on Sunday, June 20, 2004 - 11:36 pm:

Thanks to Anonymous and MG, the reason why I want to develop a method for the analysis of PCBs with LC/MS/MS is our sample matrix is a vegetable oil and the use of LC instead of GC would help me a lot in saving my time on sample clean up, We are going to receive our first APPI setup in 6 month times, by the any suggestion for fast and simple oil clean up method....We are currently using GPC as our standard method, but it seem that there is no complete clean up ....

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By Anonymous on Tuesday, June 22, 2004 - 03:34 pm:

cbyeoh,

You might want to try negative ion APCI and look for M- ions for your PCBs. While there is no guarantee that this will work, chlorine atoms have high electron capture cross sections and hence your PCBs may yield abundant M- ions.

Note, make sure that if you run in negative ion APCI mode that you use high purity (>99%) nitrogen as your nebulizing gas (do NOT use air)and that your source block and vaporizer are hot before applying voltage to the corona discharge needle.

Kevin