Chromatography Forum

Hello.
I have a problem with using custom fields in gas chromatography. When I use clear calibration in sample set and I process it using Method set with processing method chosen in Default Processing Method, then results which I get are only those, which in sample set were before the line Clear calibration.
In HPLC when I create Method Set, I choose Derived channel with wave length used in method, then I assign processing method to that channel. But in GC-FID I don't have that option, because I don't have a possibility of choosing Derived Channels. I don't know if the problem with using clear calibration is related to assigning processing method to Method set otherwise than I do in HPLC.
So I can't clear my sample set, because then I don't have all results I need. Do you know anything about clearing sample set without using clear calibration line? Or maybe do you have any ideas about creating Method set otherwise?
I will be greatfull for any help

Im not sure about GC, but for PDA data I have to create derived channels as you mention for a wavelength then associate that derived channel with a proc method. What is your bracketing standard set up? Is it possible that you have Don't Process or Report set for all the standard lines? Are you using labels for calibration correctly?
Typically, you use clear calibration to wipe points from the calibration curve that aren't suitable (like running standards directly after a system suitability standard) so to start quantitating your unknowns using specific standards, is there anything like wrong labels or wrong functions in your sample set that seems out of place?

Also, do you have the correct method set in the sample set for those lines after clear calibration? Are the channels for those lines locked? Are there values in the component editor for those lines and the standards used to quantitate them?

Thanks for answer.
Unfortunately I have already checked all the things you mentioned.
One thing I don't quite understand is what you asked about bracketing standard set up. In our sample set we inject standards at the begining, just after blank injections (clear calibration line is between blank and first standard) and before samples. After samples we inject only control standard to get RSD for whole sequence and we don't use that injection for calculations.
About creating derived channel in method set - when I try to do this, I get a comunicate "Please select a proper instrument method first" - in my understanding it means that for GC-FID methods I can't create derived channel. I thought maybe I could change instrument method first, but I didn't see any option related to creating channels.

Hmm, maybe you cant create derived channels in GC then.

For bracketing standards I mean some people run samples using a bracketing with overlap layout so if the labels used to reference certain standard injections were wrong, then you wont get any amounts.

Maybe check the tablespace in your project, you may not have enough left to generate results. Or just check what messages are popping up in the Message Centre when you process the sample set.

In Message Center I get messages for every injection, which couldn't be processed: "Error- There are no channels specified to clear in method set. This is usually caused by not specifying an instrument method in the method set - processing aborted".
Obviously I have chosen instrument method in method set before I processed sample set. Maybe I should create other instrument method only to put it in the same line, as clear calibration? But I don't know what I should change in it in relation to instrument method I use to run samples.
Any ideas?

There is obviously some conflict going on in your instrument method when it comes to analysing these samples which wont quantify, I would be having a deeper look at the settings in the method to see if something sticks out.