Column ovens and RI detectors

[dgraham]

Hi,

I have read that column ovens are important for sugar analysis. I always assumed this was to promote better and consistant column separation however I recently read that when using RI detectors (commonly used for sugar detection) that it is important to use a column oven to maintain a constant temperature and avoid baseline shift. I know that RI is temperature dependant but surely any eluant leaving the column oven will cool before it passes through the detector. Shouldn't the cells in the detector be heated to maintain a constant temperature of samples passing through? Thanks in advance for clarifying this.

[tom jupille]

0.01" id tubing has about 0.5 microliter of volume per centimeter of length. Assuming you have 20 cm of tubing between column and detector, that works out to 10 microliters. At 1 mL/min, that's a residence time of 0.010 x 60 sec = 0.6 seconds. Not much time to cool down.

And yes, many RI detectors incorporate heat exchanger tubing to damp out temperature fluctuations.

[dgraham]

Thanx for the reply!