by
dblux_ » Sat Apr 04, 2015 5:17 pm
...
Extraction: I'll centrifuge water and benzene+solvent at 600 rpm for 15 minutes,...
You need rather to shake it vigorously. Emulsion will easily disapear forming two layers when you stop shaking.
I'll put the vial at 4 degrees and when the vial reach the 4 degrees I take out 0.5 microliters of solvent+benzene with a syringe, I fill the other 0.5 microliters of the syringe with solvent + internal standard and I inject in the GC.This procedure is to reduce volatilisation and to know the partition of benzene between water and solvent.
Execute your experiment in room temperature
Is it a good way? How know the partition?
The GC column is capillary, non polar, suitable for aromatics and pesticides. Phase: bonded; poly(5%diphenil/95%dimethylsiloxane). I'd like to know if the substances mentioned above are dangerous for the column and how set this program in the best way:
Hydrogen 30 ml/min (fixed)
Air 300 ml/min (fixed)
Carrier gas: He 1 mL/min
Detector temperature: 180°C or 250?
Injector temperature: 180°C 250 or 250?
Oven temperature program: I know three program used with other column to determinate BTX, but I need to identify only benzene. Really ? Forgot about internal standard ?What is the best program?
35°C for 5min , to 70 °C at 5 C/min, to 180°C at 15C/min and hold 10 minutes at 180°C
50°C holding time 1 min, to 70°C at 5/min, to 200 at 20 °C/min and holding 200°C for 20 min
40°C for 5 min, to 48°C at 2 C/min and to 120 at 15 °C/min (no holding time at 120°C)
Injection: splitless. Why ?????????
Thanks!
Andrea
