Empower Tip: Empower CDS User Question

In this tip, we will answer an Empower CDS user question.

Q: Empower calculates peak tailing, however, how can I calculate peak fronting?

Great question. This can be done with a couple of simple Custom Fields.

The definition of USP Tailing is width @5% of peak height/(2 x front half of the peak). The front half of the peak is the time from width start point at 5% of peak height to retention time and reported as f@5%.

STEP 2:

We can calculate the back half of the peak by subtracting the front half of the peak from the width@5%.

Using the USP Tailing formula, we could calculate fronting by the following: width @5% of peak height/(2 x back half of the peak).

Alternatively, we could use the symmetry calculation which is back half/front half and flip that around to be front half/back half.

If the value is greater than 1, the peak is fronted. Here is an example chromatogram with all the fields.

It's that easy!