624 (cyanopropylphenyl) stationary phase and dichloromethane
Posted: Wed Aug 05, 2009 8:19 am
hi,
we use a Phenomenex ZB624-column (60x0.25x1.4) to separate high volatile flavors (such as acetaldehyde, propanal, methylpropanal, 2- and 3-methlybutanal).
There are small amounts of solvents (MeOH and CH2Cl2) in the sample due to the addition af standards (max. 25 mikroliters in HS-vial)
This worked very well with SPME-GC-MS (separation of acetaldehyde from the air peak, baseline separation of 2- and 3-methylbutanal, far away from the CH2Cl2 solvent front).
However, recently we observed a large solvent front and very high background on m/z 71,73,86,88,90,100,102 and so on. Therefore, the sensitivity dropped by a factor of >500.
As soon as we work with samples without solvents, the background noise disappears.
There is no leak in the system, and all possible sources of contamination were eliminated and/or replaced.
Does anyone know about incompatibilities of cyanopropylphenyl-phases with solvents?
Thanks for any help!
we use a Phenomenex ZB624-column (60x0.25x1.4) to separate high volatile flavors (such as acetaldehyde, propanal, methylpropanal, 2- and 3-methlybutanal).
There are small amounts of solvents (MeOH and CH2Cl2) in the sample due to the addition af standards (max. 25 mikroliters in HS-vial)
This worked very well with SPME-GC-MS (separation of acetaldehyde from the air peak, baseline separation of 2- and 3-methylbutanal, far away from the CH2Cl2 solvent front).
However, recently we observed a large solvent front and very high background on m/z 71,73,86,88,90,100,102 and so on. Therefore, the sensitivity dropped by a factor of >500.
As soon as we work with samples without solvents, the background noise disappears.
There is no leak in the system, and all possible sources of contamination were eliminated and/or replaced.
Does anyone know about incompatibilities of cyanopropylphenyl-phases with solvents?
Thanks for any help!