Chromatography Forum

Is it possible to adjust the amount value for calibration in Empower?

I run a method which uses bracketing standards to calculate amount of impurity peaks. The calculation is:

(Weight Adjusted Area of sample/Weight adjusted area of bracketing standard) * Purity of Standard * RRF * 0.005 * 100.

The method was validated using the bracketing standards at 0.5% (w/w), because 100% w/w is off the scale for Linearity. We adjust the final value for impurity by multiplying by this factor of 0.005.

Problem is, Empower is returning blank values for amount in our samples and giving the Q20 (flat curve) error. Is there any way to account for this in the component editor/weights or dilution fields?

Hi ,

Link maybe worth a look :

viewtopic.php?t=15593

Sorry not came across this problem .. yet

Thanks ill have a look through that thread, this is the first time I have encountered this as well!

I don't use this software but it may be a rounding problem. Perhaps if you entered the calibration as parts per hundred or parts per thousand, you remove the need for small decimal numbers.

The problem is my standards are run at the 0.5% (w/w) level and I'm using these to quantify my 100% samples. But strangely, I do get amounts for the peaks that are in my standard (say "X" active) but I'm not getting anything for the impurity peaks. I'm guessing its because I haven't named the peaks in the components tab (there are too many).

Is there any way to quantitate unknowns peaks off a bracketing standard? How do other people report impurities methods?

What's ccalref set to?

Its not set to anything, the field is blank.

I have decided to log this as an official call with Waters, I feel there is something small here that I cant see myself, hopefully they can resolve it.

Hi
guessing you have tried impurity tab , amount set to 'amount or %w/w?
with main component selected ?
Still not 100% sure on Q20 error sorry

If you assign ccalref to a component, Empower will have something to compare unknowns to and may start populating your empty fields.