CP-SIL column for GC SCD

[suki_k]

Good Morning,

We use Agilent GC-SCD, and CP-Sil 5CB column. For liquid injection of samples the maximum temperature we go upto is 200 Deg C. Is this enough when black oil is used or do we need to use black flush or raise the temperature higher to avoid contamination?

Thank you

[chemviren]

What is the purpose of your analysis? What is your inlet? Why is your maximum temperature 200 C? What are the dimensions of your current column? What is the boiling point range or carbon number range of your black oil sample?

Depending on the final boiling point of your sample, you may need to backflush. Especially if for some odd reason you are not able to exceed 200 C. Buy a Util-metal column with the CP-Sil phase if you need to.

FYI, once you pass 800 F boiling point of your sample, you're entering a region where SCD analysis is very difficult.

[suki_k]

What is the purpose of your analysis? What is your inlet? Why is your maximum temperature 200 C? What are the dimensions of your current column? What is the boiling point range or carbon number range of your black oil sample?

Depending on the final boiling point of your sample, you may need to backflush. Especially if for some odd reason you are not able to exceed 200 C. Buy a Util-metal column with the CP-Sil phase if you need to.

FYI, once you pass 800 F boiling point of your sample, you're entering a region where SCD analysis is very difficult.

We analyse separator gas, or bottom hole samples. the maximum column temperature is mentioned 350 deg C, dimensions of the column is 30mx0.320x 4micron.
we donot analyse beyond nonyl mercaptan.

[chemviren]

Separator gas, so this is a gas sample? Not a liquid?

C9 mercaptans have BP of around 400 F. This is equivalent to ~ C12.

So the question you need to answer is: What is the carbon number range of your sample?

If your GC-SCD temperature program goes as high as C12-equivalent, then anything present higher than C12 will be stuck in the column or elute after the analysis has finished. You would need to backflush immediatley after C12 if this is the case.

Since your column max temp is 350C, you could extend temperature ramp for the analysis to elute the heavier components. But you must ensure that everything elutes, otherwise you will need to backflush.