saturn 2000 and PAH analysis

[danicrd]

hello
I have a problem with Varian saturn2000/3800 equipped with 1079 during pah analysis.
All heaviest PAH doesn't exist in my chrom!
Until PAH with mass 202 the sensitivity is ok, but PAH from m/z 252 to 302 completely disappear.
I have also cleaned the trap, changed column (rxi-5sil 30m*0.25*0.25) and liner (1079 fritted liner) but no change happens.
The only thing that give some increment to signal was temp rising of trap from 220°C to 230°C
Some other condition are
InJection: large volume of 9uL, solvent dicloromethane
flow 1.3mL of helium
trap temp 230°C
t.line temp 300°C
Any advice are greatly appreciated..
Thanks to all
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[AICMM]

danicrd,

Please post your inlet conditions. With the large volume injection, if you are not losing the lighter PAH's then I would think you are not losing the heavies. Therefore, I would have to suspect you are not getting them off the inlet. With a fritted liner you should have plenty of surface are (perhaps too much?) to vaporize the heavies.

Best regards.

[danicrd]

After a visit of service engineer that cleaned the trap (already cleaned), cut off column, set temperature of ion trap to 240°C the heavier pah now are ok. The ebgineer has focused the cleaning work on gate due to discolored parts on washer side.
The inlet condition remains the same..
Middle Injector Type 1079
-------------------------
Oven Power: On
Coolant: On
Enable Coolant at: 160 C
Coolant Timeout: 20.00 min

Temp Rate Hold Total
(C) (C/min) (min) (min)
--------------------------------
0 0 0.20 0.20
330 200 4.00 5.85
300 50 25.00 31.45
200 4 0.00 56.45

Time Split Split
(min) State Ratio
----------------------
Initial On 10
0.01 On 75
0.20 Off Off
4.50 On 200
20.00 On 100

[WK]

danicrd
Top marks for replying with a resolution !
This is of interest to me who may do PAH in future by Saturn.
Regards
WK