Chromatography Forum

Any Chemstation experts out there?

We often run large overnight sample sets in our lab but occassionally the guard column becomes blocked during the run and chemstation senses an overpressure and turns off the flow.

There's nothing we can do about saving the run but the problem is that the column is then left filled with aqueous buffer overnight, which is not good.

I would like to add a macro (or something) to change the behaviour of chemstation so that when it senses an over-pressure it does not stop the flow immediately but instead switches to pumping at 0.5ml/min from the organic phase for about 30 min to flush the column, then stops the flow.

Does anyone have any idea how I can do this?

Thanks!

Nick

The ChemStation can do many things, but thinking and reacting are not always easy to do.

I will check into some possibilities and let you know if I find anything.

In ChemStation Online session, go to 'Instrument', 'Set up Pump', and set the conditions you want if it gives an overpressure. Click OK, then go to 'Instrument', 'More Pump', and select 'Control'. Select Pump On, and under Error Method, select "Take Current Method". Now the flow conditions will be stored in memory of the pump, and if the system gives an error, the pump will load that method from memory, and pump at the low flow rate with the 'flush' solvents.

Each 1100 or 1200 module has a place to save an 'error method' (lamps off on detectors, low flow on pumps, temp control on/off, etc.). The Agilent ChemStation can make intelligent decisions.

nimbi63,

Just a question: I've always used this feature of Chemstation to turn the flow off completely if there's an error (it's not nice finding all my acetonitrile pumped to waste over the weekend).

If you get a severe blockage, but the error method specifies that a flow should continue (as in this case), what happens? The pump will try to continue at the error method flow, but if it is still enough to generate an over-pressure error... is there a fall-back "really bad error" forcing zero-flow?