Compound LOD and LOQ in OpenLab CDS-Chemstation

I’m running OpenLab CDS Chemstation Edition C.01.09. I would like my final report to display “Not Detected” if the value is less than the LOD, and “< LOQ” if less than the LOQ...otherwise, display the calculated value.

 

The only way I could figure out to do this was to add two Compound Custom Fields to the method. One for LOQ and one for LOD. Then these can be specified for each compound. Unfortunately, it appears that these have to be manually entered for each sample when the sequence is created, and copying one sample to another row does not copy this information. There does not seem to be a way to copy a table of values from word or excel into this table. I have been able to alter my report to use any value given in these fields to display the text as I want.

 

Despite these difficulties in getting initial values I to the fields, is this the best way to accomplish this?

 

i do see that there is a part of the Run Time Checklist labeled “Update Custom Fields Values”. Is there an example Macro that I can use to populate these fields prior to report generation?

Parents
  • Hello,

     

    There are several ways to do this including complex solution like custom extension and external constants files but the most accessibly way is to use the compound name. One possible other solution if values are the same for all compounds and do not change that often use a report parameter. I am guessing for your report each peak has its own LOD and LOQ so that is not an option. In this case, I would suggest naming your peaks as peakname_LOD_LOQ, this might look like Methanol_0.525_1.101. Now when you need the compound name for an expression you would use Choose(1,Split(Compound_Name,"_")). When you need the LOD or LOQ for an expression, like the IIF comparison for reporting compound amount, use Val(Choose(2,Split(Compound_Name,"_"))) or Val(Choose(3,Split(Compound_Name,"_"))). 

     

    Marty Adams

  • That’s a decent idea...seems kind of like a cheap hack, but if that’s what it takes. I’d probably use the pipe as my delimiter, but it would work the same. I didn’t know about the Val() function, so thanks for that. The Compound Custom Fields still seems more “right” if it weren’t for poor interface to populate values.

    Is there an updated macro programming guide for OpenLab CDS Chemstation somewhere? The latest one I could find online has no mention of Compound Custom Fields.

Reply
  • That’s a decent idea...seems kind of like a cheap hack, but if that’s what it takes. I’d probably use the pipe as my delimiter, but it would work the same. I didn’t know about the Val() function, so thanks for that. The Compound Custom Fields still seems more “right” if it weren’t for poor interface to populate values.

    Is there an updated macro programming guide for OpenLab CDS Chemstation somewhere? The latest one I could find online has no mention of Compound Custom Fields.

Children
  • Compound Custom Fields will work and likely would the correct solution, but you have already found the workflow issue that it causes. We have gotten around this with some customers by creating a template sequence for the method with all the values filled in including the compound custom fields for more sample than they will likely ever do in one run. Then to run the system they open that sequence, update any necessary fields, and the cut out the extra lines. The new update custom field values entry in the run time checklist was placed there to allow data analysis to write a value into a custom field for reporting. An example of this is the compound mulitplier which is not available in IR for reporting. You could create a custom field for that value in the method, write a macro to copy that value during DA into the custom field, and then add that macro to your method. Now in IR you could report compound multiplier using that custom field.

     

    Marty Adams

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