drawing up a water sample with an autosampler

Discussions about GC and other "gas phase" separation techniques.

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I am having an issue trying to draw up a 0.2 uL sample with a salvaged CTC A200 autosampler. I can easily draw that amount consistently with a hydrocarbon matrix but when I try to draw that with water I usually get nothing.
I switched to a gas tight syringe but that did not help.

I am using 50/50 xylene acetone for the rinse solvent. I have tried pre-rinsing the syringe with water sample as well as only pumping sample (without pre-rinsing) but that does not seem to do it either.

If I manually sample, I can pull a water sample, just not on the CTC.


* Decrease drawing speed
* Change syringe (needle tip may be clogged)
* Use "sandwich" - i.e. air gaps before and after sample
Would an intermediate rinse with Methanol or Acetone be possible to remove any traces of the xylene that may be causing a problem with the water entering the syringe?
The past is there to guide us into the future, not to dwell in.
3 posts Page 1 of 1

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