Vinyl chloride by 524.2

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

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I know from reading threads on here that a lot of us run 524.2...I was wondering if anyone has ever experienced trouble with vinyl chloride recoveries.

We have beautiful calibrations, ICVs (separate source) within 20% and are continually failing PTs high for vinyl chloride. We've ruled out standard issues, operator issues (prep, etc) and have also analyzed different PTs on different instrumentation (an ion trap and a quad). All of our failing PTs had calibration, sequence and batch QC all within 20% so I'm stumped.

Any ideas?
We do not have issues with VC. Due to the fact you are seeing this on multiple platforms I would look at your standard and PT preps. Or a long shot the standards are not what they claim to be.
Are you using VC standards made in methanol or from gasses?

If made in methanol how do you store the standards, both stocks and working mixes?

Failing PTs high would tend to indicate you are losing some of the standard during storage so that your calibration contains less concentration than what it should have.

Also do you prepare both the PT and the calibration in preserved water? It can make a slight difference in recovery sometimes.
The past is there to guide us into the future, not to dwell in.
Back when I ran VOC analysis, we kept our 8260 gases stock and working standards separate from the mega mix. It was our experience that the gas standard, once removed from the flame sealed ampule, was only good for 7 days. Additionally, we would not use it for calibrations if it was older than 5 days.
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