Chromatography Forum

Hello all-

I am having a bit of an issue setting up these custom calculations. Here is the background.

Using either a dual wavelength UV or a PDA, we are quantitating peak one and peak two within the same run. Peak one is calculated using a wavelength of 224 nm and peak two at a wavelength of 282 nm. I know pretty well how to set up other calculations, but this one is giving me trouble. How can I set up the custom calculation to calculate only peak 1 at the 224 nm and only peak 2 at the 282 nm? It is also necessary for it to be able to quantitate using either the UV or a PDA, if this is possible.

Thanks

I don't know if this will help you but I've been reading about Empower custom calculations.

1. Go to Manage -> Configure -> right click your project of interest -> properties -> go to custom field tab and then click new.

2. I assume you'll want to compute the ratio for each peak so select that option, also probably set it as "Result Set Only"

3. Empower syntax works like label.injection.channel.operation(field) or just label.injection.channel.field, so if you wanted to compute the different ratios for the peaks you would probably do something like =...channel1(Area)/...channel2(Area) I'm not sure but I think the ... modifier means you're leaving label and inj number blank so then you'll only look within your sample?

Maybe someone more experienced can chime in here

have you already played with the "channel reference field" in the processing method \ component tab?

with that you can control if the peak is quantitated on a specific channel only.
in any other channel, the peak will only be integrated as "unkown" peak type, without its component name.
maybe you'll need two processing methods for PDA and TUV detectors, if the channel names are not identical

Easier than you think!

First you need to add label claim fields to the sample set via custom fields

Next you create two custom calculations fields based upon each label claim. The rest of the info peak area, std conc, dilution and sample weight would all be in the sample set or part of the amount calculation.

Then you use savvy when you create your reports and only add the custom calc need for the peak of interest to the table which will display it. Also, filter by channel and peak name for that table.

When you process use both processing methods in your method set and the standards I your sample set.

Do the same for the other component.

I do this routinely.

Regards,
Art