Chromatography Forum

Hi

I you run a HPLC method using 1% Formc acid in water/1% AcCN to 100% AcCN with a 3 micron 50 mm column, what kind of flow rate is ideal in a waters 2695 instrument ?
Also, I do not use a column heater.

Appreciate your response

thanks

Depends on the column diameter, what kind of samples you run, and how much time you want to spend on the method.

Assuming that you have a 2 mm column and an analyte with a MW around 200 t0 250, you want to run at 1.5 mL/min for a 1 minute gradient, at 1 mL/min for for a 2 min gradient, 0.6 mL/min for 4 min, and 0.5 mL/min for an 8 minute gradient.

I am using a ID 2.1mm column. According to your suggestion, I will have to run a 0.4 - 0.5 ml/min flow rate for a 5 min method. I hope that will not cause any back pressure issues.

thanks

Especially if you heat-up your column (40-50°C will be ok), you'll not have any pressure issue.

Thanks for the suggestions.

The values were estimates for room temperature, as you said that you do not have a column heater. Backpressure is not a problem.

Excuse me JoseM. Reading Uwe's last post I saw you haven't the heater. I've lost this information in your first post.