morsagh
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GC analysis
So i am going to do gas chromatography analysis of mixture of camphor and borneol but problem is i don´t know what methodics should be used (like
which column: general C18, DB-23 or FFAP?) I really don´t know a lot about GC so thank you very much for any help. (gas chromatograph is with FID
detector)
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Heavy Walter
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Hi
A GC capillary column as HP-5 will do the separation.
But you don't mention some aspects: trace level or %? Are you trying to see the borneol metabolite in mammals or just to separate a mixture of both?
Assuming you will try fist a solvent dilution of both analytes begin with these GC parameters to start: Inlet temp 200°C; oven ramp from approx.
80°C to 150 °C (play with the rate); FID temp 300°C.
Flow through column 1 mL/min (He) and split ratio depending if are traces or %.
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morsagh
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It is mixture after reduction of camphor so i want to know quantity of borneol (so in %), and if there any borneol is in significant content. So what
solvent should i use and why oven ramp 80-150°C and what starting and final temp? Thank you so much for help.
[Edited on 26-1-2016 by morsagh]
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Heavy Walter
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Hi
Just dissolve them in hexane.
The oven program is just a suggestion.
As you only need to separate two compounds, the oven ramp will be simple. Start at 80°C, remain during 1 min and then ramp the heating by 20°C/min
to ending at 150°C.
Prepare two separate standards in hexane, inject them separately and you will know each retention time. In case they are too close prepare the mixture
of both and run again.
During analysis you will monitor the peaks coming out and you will decide if they are well separated. If not, you can play with lower heating rate or
lower helium flow.
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morsagh
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What should be used to clean injector? Will acetone work?
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Heavy Walter
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So the system has been down for a while?
The inlet has a glass liner, that will keep most of the dirty stuff.
In case you suspect contamination, yes, you can take out the liner and with cotton hyssop and acetone clean all the cavity. I am not familiar with
that GC brand but I assume it has some seal at bottom of inlet. Check if it is clean.
In case of doubts, post pictures.
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morsagh
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So i was doing GC analysis of my sample and my question is was my reduction successful (at least 0.2%)? I don´t understand GC very much so i please
your help.
Thank you very much
graph is in attachment
Methodics used:
initial temperature 60°C hold 1 min
ramp 12°C/1min up to 160
column HP-5
FID 300°C
concentration was 5mg of sample on 50μl of hexane.
Attachment: concentration 5 100.pdf (13kB)
This file has been downloaded 419 times
[Edited on 24-2-2016 by morsagh]
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Heavy Walter
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Hi
I assume you dissolved your standard and that your product is at time 5.88 min.
At Data Analysis go to Graphics / Signal Options and select "Autoscale". That will let you see your peak.
Make some other dilutions in order to prepare a calibration curve.
Let me know if you need more help.
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