dinitropyrenes' determination

[acetonitrile80]

Hello everybody,

I'm doing analysis on NHAP and OPAH by GC-NICI/MS. I have tested different capillary columns (Agilent, 5MS 30 m x 0.25 mm, 0.25um - OPTIMA 17MS, 30 m x 0.32 mm, 0.25 um and 17 MS OPTIMA 30 m x 0.25 mm, 0.25 um). In all cases, I used the pulsed splitless mode (injector T = 230 ° C, with a pression of 30 psi). Only with the column 5 MS I am able to determine the dinitropyrenes. Could anyone tell me why? Thanks

[rb6banjo]

Have you tried adjusting your injector temperature hotter? Pyrene itself has a boiling point of around 400 °C. 230 °C is probably on the low side for good vaporization of the analyte(s).