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- Posts: 1
- Joined: Thu Oct 21, 2004 9:49 pm
we'va been working in a calibration curve for static headspace BTEX (aromatics compound) determination, which gave us a terrible headache.
So which is the problem?
We own a 7694E head space sampler associaded with a needle trough septum to a HP 6890 GC Mass Detector.
As long as two months we got a not variability response and acceptable calibration curve. Since two weeks has apear an non inexplicable aleatorius factor that make all our research go down.
We tried everything, as vial pressure, carrier pressure, leaking fenomena,
equilibrium time, loop fill time, loop equilibrium time,etc...
We going in a splitless method (0.01 to 0.10 ppm sampler concentration)
-vial pressure (6 to 28 psi) each try
-carrier pressure (60 to 75 psi)
-loop equilibrium time (0.15')
-vial equilibrium time (30')
-vial temperature (90ºC)
-inject time (1')
-transfer line (150ºC)
-loop temperature (135ºC)
would you please there is someone who can help us?
So which is the problem?
We own a 7694E head space sampler associaded with a needle trough septum to a HP 6890 GC Mass Detector.
As long as two months we got a not variability response and acceptable calibration curve. Since two weeks has apear an non inexplicable aleatorius factor that make all our research go down.
We tried everything, as vial pressure, carrier pressure, leaking fenomena,
equilibrium time, loop fill time, loop equilibrium time,etc...
We going in a splitless method (0.01 to 0.10 ppm sampler concentration)
-vial pressure (6 to 28 psi) each try
-carrier pressure (60 to 75 psi)
-loop equilibrium time (0.15')
-vial equilibrium time (30')
-vial temperature (90ºC)
-inject time (1')
-transfer line (150ºC)
-loop temperature (135ºC)
would you please there is someone who can help us?
