Chromatography Forum

Hi,

Im running empower2 - a relsubs method.

I have 1 sample which is injected twice and quantitated against 2 standards. I've made custom field to mean the amount result of named components. The porblem is that this does not work for unknown peaks which do not have components.

Is there any way of doing this? Grouping retention times doesnt work in report publisher.

Thanks

I believe I remember reading somewhere that

SAME.%.%.AVE(Area)

will average peak areas of injections with the same name. Dunno if the components have to be named as well for that to work though.

do you realy need a custom field for this?

maybe there are some possibilities by just selecting/modifing the right report method.

When you go the table parameters you can activate some statistical calculations like average and %RSD.

Maybe you also have to set the report method setting from individual to "by vial" (or similar)

The custom field would only work if the "unknown" has a component set up.

I've tried all sorts of modifications in the report method.

The problem is that empower is recognising the fact that the impurity is the same in both chromatagrams. I can't select in the report method to group by RT as these, although simiar will not be exactly the same. This does how if I take the presicion down to 0. However this isnt the best approach.

I see..

I think, with just the plain retention times this is probably can't be done (easily).

Best would be that you give a name to your unknowns, maybe somthing like unk1, unk2... or just plain numbering like as 1,2,3... so the software can recognise them as compounds (hope there are not too much and different in each sample...).

But then it can probably be done without a custom field, just by the report method

Name a component as your CCalRef1 in your processing method. From there, (CCalRef1[Amount]*100*Area)/(CCalRef1[Area]) (or something close to this) would yield wt/wt pct vs. your CCalRef1 component amount as long as your report includes unknown peaks.

The custom field would only work if the "unknown" has a component set up.

I've tried all sorts of modifications in the report method.

The problem is that empower is recognising the fact that the impurity is the same in both chromatagrams. I can't select in the report method to group by RT as these, although simiar will not be exactly the same. This does how if I take the presicion down to 0. However this isnt the best approach.

How about using RT Ratio? Use one peak as default peak, to calculate RT ratios.

Ace

Thanks for your replies.

The problem still is that I cant group the same unknown peaks from the different injections together and take the mean from them.

If I group them by RT ratio then as before I have to take the number of decimal points down to 1 or 0.

Surely there must be another way?!

if RT ratio and/or RT are different more than 1 decimal, how do you want to let the software group the unknown peaks?
The only way I can suggest you is to name the peaks, but you can name them unknown_1, unknown_2, ...

Ace