For school we have to create a temperature program for the optimization of a separation with hydrocarbons (benzene, toluene, xylene all in several variations soluted in methanol). There is a lot stuff to find on the Internet, but most of them are too difficult for us to understand (second year College).
I hope someone can help us with information or an Internet url so that we can finish our research for our project.

Regards

Jorim & Wouter (Netherlands)

PS It is not necessary to come with a complete temperature program, what we like to now is: How to make our own temperature program.

It's not just the temperature program, it is also the column phase and dimensions. A very good starting point is a column manufacturer's catalog or website.

ps I usually do not respond positively to requests for homework help, but you asked where to find information to complete the project, not for a complete solution to the project.

Thanks for your advice, but use a different column is not something we could de. We have to use the column thats now in place (school's and money??). So we have a RP C18 column and thats it!

ps I now what I ask and we want to create it self! So a complete solution is not necessary

It is not GC you want. It is LC if your column is a RP C18. I assuming this is a 25cm 5 micron C18 reverse phase chromatography column.

Tell us if this is not correct, please.

Anon

Me mistake.
Ad the moment were busy with the theory of GC and HPLC so I had turned around it.
We use a column that is suitable for the detection of hydrocarbons and for our project we have to wright a temperature program.
But the problem is that I can't find nothing about the theory behind temperture programming. I'd hoped someone had for me understandable information or an Internet url what can help me to write our program.

Thanks,

Jorim

Jorim,

There is a good explanation of processes by Grob here which might not turn up on Google.

http://www.restekcorp.com/advntage/d96grob.htm

Regards,

Ralph

Nice url

Thanks Ralph

Dear Jorim,

It is hard to construct a temperature program without some specifics of a method. What are the column dimensions? What is the carrier gas and what is it flow rate? What is the sample introduction technique? These are the most important factors affecting the temperature program.

There are some general rules, however [1-3].

DEFAULT CARRIER GAS FLOW RATE, F. There are two important rules [1,3] for selecting F. First, F should be proportional to column diameter. Second, F for helium should be 20% lower than F for hydrogen; F for nitrogen should be 1/4 of F for hydrogen. You can compute F for your column starting from this setpoint: for a 0.32 mm open tubular column, F for hydrogen should be 3.2 mL/min. With so chosen F, it is the most likely that the shortest analysis time for your separation needs will be achieved.

DEFAULT OVEN HEATING RATE [2,3], R. Measure or calculate the hold-up time, tM, for your column and the carrier gas flow rate at the initial oven temperature. R should be inversely proportional to tM so that it is always 10 degree Celsius per tM. For example, if tM = 1 min then R should be 10 degree Celsius per min. If tM = 2 min, then R should be 5 degree Celsius per min. With so chosen R, it is the most likely that the shortest analysis time for your separation needs will be achieved.

Good luck,
Leon

References

1. Blumberg, L. M. "Theory of Fast Capillary Gas Chromatography. Part 3: Column Performance vs. Gas Flow Rate". J. High Resolut. Chromatogr. 1999, 22, 403-13.

2. Blumberg, L. M.; Klee, M. S. "Optimal Heating Rate in Gas Chromatography". J. Micro. Sep. 2000, 12, 508-14.

3. Klee, M. S.; Blumberg, L. M. "Theoretical and Practical Aspects of Fast Gas Chromatography and Method Translation". J. Chromatogr. Sci. 2002, 40, 234-247.