Chromatography Forum

Dear all,

after few days of struggling to create a proper Intersample custom field, I am asking for your help!
We need a custom field that always compares two repeated measurements (e.g., first and second) for the same batch and storage condition and this custom field should return the absolute difference in LabelClaim_Pct.

Here is one Formula I found to be working but it only calculates two samples by labels:
ABS(U1.1.(CCompRef1[LabelClaim_Pct])-U2.1.(CCompRef1[LabelClaim_Pct]))

But it is useless when we perform our stability analysis containing 24 samples.
So I figured that I need to add [Batch] and [Storage_cond] Custom fields into the formula, because we always perform two measurements for one batch+storage condition. But all my attempts are faulty...

I would be eternally grateful for your ideas!

Thank you and best wishes
Marina

Perhaps you are over-complicating it?

Hint that may be helpful - samples with different names can have the same label.

IE: CU samples 1-10, all separate preparations from the same lot of tablets can be named LOT123-01, LOT123-02...LOT123-10 and all have label U0101.

Then you do your summary statistics table by label, so each lot gets its own table.

Perhaps you are over-complicating it?

Hint that may be helpful - samples with different names can have the same label.

IE: CU samples 1-10, all separate preparations from the same lot of tablets can be named LOT123-01, LOT123-02...LOT123-10 and all have label U0101.

Then you do your summary statistics table by label, so each lot gets its own table.

Thank you for the great idea, DR,
but the issue is that for our stability studies in ICH/GMP it is very important to keep the data such as: batch nr.; the time point and the climatic conditions as raw as possible. Meaning it cannot be altered.

So I really need a custom field that includes batch and climatic condition (also CF) to filter the results. Do you know the operation that filters the results?
The most recent CF that kind worked was this one:
ABS(EQ(Batch, Batch) * EQ(Storage_cond, Storage_cond) * ABS(U1.1.(CCompRef1[LabelClaim_Pct])-U2.1.(CCompRef1[LabelClaim_Pct])))

The issue is that it does not use Batch to filter the Samples.. Is there any way to make it better?

Thanks a lot for your time and support!

Regards
Marina