Empower Tip: Review Window and the Processing Method

From time to time, I am asked if Empower can subtract a 3D baseline from 3D data such as from a PDA. If the method calls for a gradient and the gradient results in a rising baseline, it may be desirable to subtract the baseline across the wavelength range. Sound complicated? It’s very easy to do.

We begin by bringing a Sample Set into Review, open and apply the Method Set. The mobile phase in this case is water/acetonitrile and the gradient goes from 7% acetonitrile to 20% acetonitrile in 1.5 minutes. We see the resulting rise in the baseline for the blank.

Go to the Method Set window, enter the label for the blank injection into the PDA 3D Blank Subtraction field. The label comes from the Sample Set Method and in this case is simply B.

Save the change to the Method Set, return to the Main Window and reapply the Method Set. Notice that the baseline for the blank is a straight line, i.e., it subtracted from itself should result in a straight line.

Select one of the standards or samples and zoom in on the baseline. Notice the flat baseline which results from subtracting the blank baseline.

Finally, I have included an overlay of the baseline for the sample without the subtraction (blue) and with the subtraction (black).

It’s that easy!