GCMS: BFB Increasing With Spike Samples

[morganschimelfenig]

Hello,

My team and I are experiencing some issues with our surrogate, BFB. We are seeing an increase in our spiked standards. For example, our calibration goes from 0.2ppb to 40ppb and our response for BFB will double in response between those calibration points. We also are seeing an increase in response between CCV injections and sample/MB injections which have no standard in them besides the IS and surrogate.

I am hoping someone can help me to determine what the issue is. We have manually injected just IS and IS+CCV and it follows the same pattern eliminating most of the purge and trap autosampler. We have also just spiked CCV and just spiked BFB into vials and there seems to be nothing in the 8260 standard that would cause in increase in the response.

Let me know what you think.

Thanks,
Morgan

[James_Ball]

It is a common problem, and happens more with Dichlorobenzene-d4 surrogates and internal standards than even with BFB. What I have found is it is related to total mass injected even more so than amount of methanol from the standards.

What GCMS and P&T are you using?

Have you cleaned the source recently?