Our system is 7820A/5977E we have a tailing problem during PAH's analysis.
The method we used is:
Injection Volume: 1 µl
55 C held for 5 min, 25 C/min to 320 C, held for 3 min
Carrier gas: He 1.5 ml/min
Column: HP 5: 30m x 0,25 mm x 0,25 µm
Liner: 4mm id, dual taper deactivated, no wool
Acquisition mode: EI, SIM (1 to 200 pg)
Aux: 290 C, Ions Source:340 C, MS Quad: 150 C
What we made until now is:
Cleaning the Inlet and the ion source, using different Liners. increase Transfer line temperature to 340 C. Change the column, new pre, and post-column, Septa and O-Ring, different solvents, bake out the MSD, and different PAHs standards.
18/69 = 0.59 Water% (counts=5538)
28/69 = 2.36 Nitrogen% (counts=22200)
32/69 = 1.29 Oxygen% (counts=12140)
44/69 = 0.17 Carbon Dioxide% (counts=1586)
Any comments and suggestions will be appreciated