Chromatography Forum

Hi all

I wish to do a hot needle injection with my 7683 autosampler. What is the best settings to accomplish this

SGE recommends a 5sec preinjection delay (which automatically activates the hot needle configuration with a 1ul air sandwitch) and a 15 second post injection delay for manual injection. Is that also the best for using the autosampler?

http://www.sge.com/uploads/14/eb/14eb5f ... 0046-S.pdf

The best is what works the best - you have to try some settings and see which give the best results. 15s post injection sounds way too long to me. Start with 3s and 3s and work up in increments of 1s.

Peter

Hmm the method I was reading is old. It recomended hot needle. From what I understand modern autosamplers are so fast that it is not really necesssary as the injection is so fast there isn't time for anaytes to condense in the needle.

I'll try it anyways but it will likely make no observable difference.

I have consistently found that, with methanol as a solvent, doing a hot needle injection with a 3 s pre-injection delay gives better repeatability than the default fast cold needle injection.

Peter