Chromatography Forum

Hello together,

i need to change an established PAH method. The reason is that i have to analyze four more PAHs. These new PAHs have a higher evaporation temperature and i cannot find them with the method we actually use.

- Benz[a]anthracene
- Benzo(b)fluoranthene
- Benzo[a]pyrene
- Chrysene
- Dibenz[a,h]anthracene
- Indeno[1,2,3-c,d)pyrene
- Benzo(k)fluoranthene
- Benzo[g,h,i]perylene

GC: Agilent 7890A
MS: 7000A Triple Quad
coupled with a CIS and TDU from Gerstel.

As i am new to GC MS MS (or the system we use) i am a little shy/careful to just change some of the parameters like source or cis temperature, cis injection speed and so on.

Does anyone already have an established method or know what i could change or try ?
I can provide any additional information

Thanks a lot

What are the concentrations of your lowest standard?

For large volume injection of those analytes I would not adjust the inlet parameters except possibly the upper temperature, but any of those will vaporize even with the inlet at 250C, 275C is a little better but you don't need anything drastic.

Using a 5 phase column (Rtx-5ms or HP5-MS ect) you will need to go to about 325C on the upper end of the oven program but they will all elute at those temperatures.

I've had really good luck with an Agilent DB17MS column.
Inlet temp at 280C, ramp from 75c to 300c.

TomC