Chromatography Forum

Hey I'm trying to do a very simple calculation; % of active area.
Calculation:
peak area/active peak area*100

Empower Calculation:
Area/CCompRef1[Area]*100
Peak type, real, result set only, sample type: Unknowns only, Peak: All.
And I have CCompRef1 set to the active peak i'm interested in in the processing method.
It worked once, then all of a sudden it stopped working. Anyone have any ideas?

I also have a boolean field to say yes or no if the result is >0.1%
GTE(Percent_Active,0.1)
0 = No
1 = Yes

Hi cody84,
From what you have posted the field should work fine - it could be something simple you have overlooked...
What happened when it stopped working?
Is the field blank or not present? (if it is not present, the custom field is either not selected in your view or not present in the project you are working).
Are other custom fields being calculated correctly – i.e. is calibration or quantitation occurring for both the peak and the active peak?
Otherwise, look at the components tab of your processing method and that CCompRef1 is filled correctly.
Hope this helps,
Ben
p.s. your Boolean field will return at >=0.1%

Hey, thanks for the reply. Currently this is the only calculation that I have. Component tab is set up correctly, sample type for theinjection is right...
The only thing I think I changed when it stopped working was the integration...but I still see peaks that are larger than 0.1% and even if they were all below, the one time it worked I had it report "n/a" if the peak was below requirements.
Yesterday I tried another simple calc:

CCompRef1[Area]\CCompRef2[Area]

With both peaks set up right in the component tab and that didn't work. FYI I'm clicking all parts of the calculation in...not typing them in.

Is it possible it could be an access rights thing?

Ok I just remembered what I changed to make it work. It was sample type, restarted and it worked.
Then I changed the GTE to >=0.10
with the '0' added at the end and changed sample type to unknown instead of All and it didn't work again.

Apologies, I didn't mean to complicate things...
GTE(Percent_Active,0.1) was the correct syntax for the field so no need to change this...

(I just was splitting hairs as this would be true at >=0.1 rather than >0.1!)

Field Percent_Active should work fine with unknown sample type and the second field with the syntax you used originally.

If the custom fields are still not working and all parameters are correct, then check that the peaks are quantitated correctly, i.e. both active and current peaks have been both integrated and peaks matched to the correct component names. If not, the fields cannot be calculated.

Update with how this works out,
Cheers,
Ben

hey, so I got it working...sort of. It was the specific chromatogram I was working on. It works fine on other ones, I have no idea why. It was probably working the whole time.