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- Posts: 3
- Joined: Thu Jun 30, 2016 1:07 am
My lab is moving from a Rxi-5ms 20m column to a BPX5 30m column for analysis of ignitable liquids (both petroleum-based and water-soluble). We use helium as a carrier gas with a Shimadzu GC-2010 Plus gas chromatograph fitted with a Shimadzu QP2010 Ultra mass spectrometer detector and Shimadzu AOC-20i autosampler.
The internal diameter of the column is 0.25mm and the film thickness is 0.25 micrometers. All analyses look fine except the diesel chromatograms do not resolve pristane and phytane. Our method includes an injector temperature of 240 Celsius, injection volume of 1 microliter, split mode of 15:1, and column flow of 1.5 mL/min.
The temperature program is 37 Celsius for 2.5 minutes, ramped to 290 Celsius at 10 degrees/min and held for 5 minutes.
I looks like pristane and phytane are coeluting with the n-alkanes and was hoping anyone could help me improve my resolution to separate the peaks.
Thanks!