A student whom I know wishes to do some DNA melting experiments, following them by UV/VIS spectrophotometry. What sort of solvent should she use for a recirculating bath? I have used ethylene glycol/water for low temperature work, but I have not done much high temperature work. If anyone knew of a Methods article on this subject, please feel free to pass along the reference.

For high temps silicon and mineral oils are well suited, but are really only necessary if you keep the bath at high temps for long times (high throughput PCRs are often used in these baths kept at denaturing temps).

 

Most ethylene glycol mixtures are suited up to 100 C, which is generally enough for melting experiments. However, in lab courses I know people doing denaturation at 95C simply with water. It depends a bit on the desired throughput and accuracy.