How to program autosampler injector on HP1090 for gradient?

[wfanumn]

For example, the dwell time of my old HP1090 is about 0.5 min. How to program autosampler injector to delay 0.5 min? Which means start injection after 0.5 min of gradient.

thanks a lot.

[mbicking]

There is no easy way to do this on an Agilent system. It may be possible using the injector program feature and some external signals/contact closures. I am familiar with injector programming, but I don't remember if you have any external contacts on a 1090.

The bigger question is why you are worried about a 0.5 min delay volume. Under typical flow this means a 30 second delay, which is usually not significant for most gradient separations.

If you are doing fast LC with small columns and/or particles, then the 1090 may not be the best instrument to use, since the detector cell may be too large and the response too slow.

More details might be helpful.