Serpentine flow in post column derivatisation

[Ary]

Just to let everyone who contributed to this thread a few weeks back know that I've manged to build two of these and they do indeed make a noticeable (2-3 fold) difference for our particular application. Thanks again for everyones input.

[Rob Burgess]

I'm looking to do some high temp. LC (up to 250°C) in the near future and believe this serpentine tube could help me with pre-heating / cooling of the MP pre and post column. Any opinions on this intended use?

To Mark Tracy, do you supply that product from distributors in the UK do you know? If not what our the order part numbers from the US?

[Mark Tracy]

Dionex and several other vendors sell eluent pre-heaters based on convoluted stainless steel tubing.

None of the polymeric tubing is rated to 250 °C; you can take PTFE to 150; PEEK or ETFE are stronger than PTFE at room temperature, but have lower melting points.

For operating at 250 °C I would suggest a countercurrent heat exchanger. I have made them by twisting together two pieces of that flexible capillary that Agilent sells and silver-soldering them together.

Dionex is represented in the UK, write to info@dionex.co.uk or call +44 01276 691 722

[Uwe Neue]

Send me an e-mail! I will instruct you how to build an efficient tubing yourself in an easy way.

[Ary]

Rob

It depends how you are planning to run your high temp chromatography. I actually use an Agilent 1100 with the column oven set to 80C to preheat. I then start my gradient as close to 80C as possible. I am only using water in my high temp system so I always run gradients. Working in this way I dont find this causes any problems. I use a standard GC for my oven and a short piece (~10cm) of tubing before the column is sufficient to give good results. Columns are my main problem. They dont particularly like gradients and tend to die after a relatively short number of injections(30-50). If you have any tips on that I would be pleased to hear them. The best so far has been Xterra.

Cheers

Steve

[Mark Tracy]

The Agilent column oven uses countercurrent heat exchangers of the type I described, so you don't need to make one if that is your oven. You can examine one to get the idea if you need to make your own for some other purpose.