Chromatography Forum

But a dwell volume difference shouldn't affect the peak width!

Right - If there was a mention of excessive PW, I missed it... I guess it can be inferred from matching RTs but with diminished R. If it were due to significant dwell volume differences, the RTs probably wouldn't match.

Going by the chart, it looks like <10µL is needed to prevent significant loss of R.

Rereading the original post... 14 seems like a pretty steep R requirement!

Given the fairly short RTs, I think it may be helpful to know the gradient program and how well the RTs match.

Hi Amat

The problems are:
1, The Waters connectors differs the connectors of other companies. Cut the old fittings, and make new ones.
2. What is the colunm temp.? If the col.temp is high You should use preheater capillary. The col. heater systems of Agilent and Waters are different.
3 Ask a Waters guy change the std 0.009" cappillary to 0.005"

You have a tiny column that can be subject to a ton of extra-column bandspreading. the probelm could also be associated with a gradient delay, but let us look at the post-column problems first.

1. What was the detector, and what was the detector cell volumn on the Agilent system? What is the detector on the Waters system, and what is the cell volume?

2. What is the diameter of the connection tubing to the detector cell?

3. What is the sampling rate or time constant setting for the detector? What was the setting on the Agilent system? Your peak width is around 1 sec. If your sampling rate is in the same ballpark, your peak will be much wider than it should be.

If you would have given us the information about the column dimensions and the retention times up front, we would have gotten to this much faster. Plus, I still would like to know what your flow rate is...

DWELL VOLUME IS 70 ul