Results only being calculated randomly
Comments
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Hi,
Haven't had this issue before, but we do a lot of work with custom fields.
There are a few things which I suspect you will have checked already, but which could cause this kind of issue.
Do all the samples have an Area for the components in the table? The calculation will still fault if the peak is missing as it won't have an Area value to reference.
Similarly, does the last result processed with label D (not necessarily the last sample injected with label D) have a peak area for XYZ?
The processing order isn't necessarily the same as the injection order, so it might be worth using processing commands in the sample set to ensure that the sample or samples with label D are definitely processed before the samples with which they are compared.
When a result set gave different results when re-processed using existing integration, am I right in thinking that some of the samples had been re-integrated?
There might also be a problem if the sample labelled D is a Standard. Does the calculation produce the same results if the Sample Type is set to All?
If you want to return 0 for "no area" and assuming there will always be a XYZ[Area] in sample D, does this field work instead?
10*REPLACE(Area,0)/D..(XYZ[Area])
Hope this helps, or at least clarifies the issue for others.
Regards,
Kenny.
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Hi Kenny,
Thanks for the reply.
Yes all of the components have an area in the results table but the custom field I require still shows 0.000000. There is just the one injection for sample with label D. It is basically a dilute solution (1/10) of any sample and the main peak area from that injection is used to calculate the impurity content for all samples in the run. Its an old method from the days when chromatograms used to top off for the main peak.
Since posting this, I have realised that the channels were not processed in the order they appear in the sample set. So I have the following:
Dilute Sample (Label D)
Sample 1
Sample 2
Sample 3
Sample 4
Empower processed as follows (as an example):
Sample 3
Sample 4
Dilute Sample (Label D)
Sample 1
Sample 2
So only samples 1 and 2 have results calculated as samples 3 and 4 do not have the required input value from the Dilute sample. Is there any reason this would happen on Empower? I have a quantitate line and summarize custom fields line at the end of the sample set. So I thought it would process in order of injections and summarize any intersample custom fields at the end? Should I use other functions or labels? I am not using U101, U102 etc labels here.
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It could be worthwhile giving all the samples a label just to be absolutely sure about the processing order:
Label Sample Processing Processing Command Label Reference D Dilute Sample Don't Process or Report U01 Sample 1 Don't Process or Report U02 Sample 2 Don't Process or Report U03 Sample 3 Don't Process or Report U04 Sample 4 Don't Process or Report Normal Quantitate D Normal Quantitate U* Normal Summarize Custom Fields I can only guess as to why the processing order would be different from the injection order, but I think at least some of the processing occurs in parallel. I've seen the odd injection process "out of order", so I tend to ensure that my reports don't depend on the Result ID or Processing Date. It might happen if it takes longer to process the dilute sample than it does to process the others. For example, if the dilute sample has a longer run-time, has more peaks, uses a different acquisition data rate or uses a different processing method it could finish after the earlier samples...
I think the processing commands should sort this out though.
Best of luck!
Kenny.
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Hi Kenny,
The labels worked a treat! Thanks for that. I am still unclear why it processes channels in incorrect order as the dilute sample only has one peak to be integrated so it should not take that long. At least the labels will ensure it works 100% of the time.
Thanks
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