Chromatography Forum

What's the difference between function Condition Column and Equilibrate in the Empower3 Run samples sequence?

Which one should I use for post-sample column wash when using gradient elution?

Thanks.

If you want to have a gradient run to flush out a column, you want to use Condition Column. I think Equilibrate just runs it at starting conditions for a period of time.

DR, you mean that Empower would only work the first condition? For example this gradient.

• t/ A% / B%

1 /100/0
2 /50/50
3 /0/100

Would it only run the first condition (100%A) for 1 minute (or for 3?) Or would it run the whole gradient and end at the first condition (100%A)?

The logic behind Empower is a bit different to that of other CDS.

Think of two indepentend timer clocks, one for Empower and one for the HPLC.
At inj.start, the instrument.method is sent to the systems and both counters are set to zero. Empower then just reads what comes from the detectors while the system is working according to the instrument method settings and its own timer.
When the "Empower-clock" is over, Empower just sends a new inject command and the systems reset their timers to zero; regardless at which point of a gradient they are.
If no new injection occurs, the system will pump at the last known condition or as long as your solvent last.

Therefore you need to program your gradient so that it will go back to initial conditions for equilibration for next injection. Also program the run-time accordingly.
This concept may be strange at first sight but adds a lot if flexibility.

If you don't want to collect the data of the re-equilibration step, use the "next inj-delay" column (maybe hidden column).
Use the equilibrate or condition column for pre- or post-sequence column rinse. It does like DR said.
Equlibrate just pumps at initial conditions for the whole time set in the "run-time" column while cond-column also runs the gradient table. For both, no injection is made and no data are stored

E.g.
t/%B
0/0
1/50
3/100
3.5/0

Then set the runtime to (3.5+equib.time) or use 3 in runtime and (equib.time) in "next inj delay"

With "equilibrate, 10min", it will pump 0%B for 10 min.
With "cond.column, 10", it will run the whole gradient and keeps pumping 0%B for the last 6.5min

DR, you mean that Empower would only work the first condition? For example this gradient.

• t/ A% / B%

1 /100/0
2 /50/50
3 /0/100

Would it only run the first condition (100%A) for 1 minute (or for 3?) Or would it run the whole gradient and end at the first condition (100%A)?

Equilibrate = 100% A
Condition = complete gradient

Hello,

Equilibrate = set the solvents mixture to the INITIAL conditions.
Condition column = run the gradient without injecting a sample.

A sample set can be look like:
1) equilibrate (for a specified time, usually 10 - 20 column volumes)
2) condition column (time = the total time of the programmed gradient, e.g. 5%B to 95% B in 15 minutes, thus the time for the column conditioning = 15')
3) equilibrate (see step 1: the column is equilibrated at the INITIAL conditions of the gradient)
4) Run sample
5) equilibrate
6) Run Sample
7) End of the sequence: stop the pump by loading a method with flow = 0.00 ml/min. To run this method, use CONDITION COLUMN for 0.1 min.

You could skip the the equilibation step between samples by programming the equilibation step at the end of your gradient. You can use RUN TIME and NEXT INJECTION DELAY to control when data are stored and when data acquisition is stopped.

I hope this clarifies the question.