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Internal Standard Fluctuation EPA 8260

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

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HELLO~

Anyone out there offer some suggestions as to why internal standard, most notably ion 96 fluorobenzene decreased in area counts from intial cal. The area of 96 was very stable over months, then dropped 40 %, HOWEVER, once a "high" concentation sample is analyzed, the area bounces back, then after 2 or 3 sample comes back down. I have changed analytical trap, did some tubing changes with the concentrator, Velocity, and still no solution. The other compounds are also depressed in area counts, but ion 96 is the most noticeable. Seems to point to an active site that is passivated with a high concentration sample? Where would this active site be?? Please help with any suggestion. Oh, the transfer line was also changed with no help.
Better Living Through Chemistry...

I hope it help:

J Chromatogr B Analyt Technol Biomed Life Sci. 2009 Oct 1;877(27):3201-9. Epub 2009 Aug 21.
Internal standard response variations during incurred sample analysis by LC-MS/MS: Case by case trouble-shooting.

Tan A, Hussain S, Musuku A, Massé R.

Quite interesting paper. If you do not have access to full article please let me know.

Hi dr-pyrex

I would greatly appreciate it if could send a copy of that paper

My e-mail is chroman.ms@gmail.com

Thank you in advance
3 posts Page 1 of 1

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