Chromatography Forum

Hi guys,

I'm just doing my data analysis at the moment and I noticed something very odd with a small set of samples that all used the same method.

Whenever I acquire data, I select the option for saving a copy of the method with the datafile.

When I look in the .M file inside each datafile, the acq.txt shows a method that it 20.87 min long, the same as my 'slow-ramp' method.
However when I look at each datafile the chromatogram shows that the run ends at 18.2 min, so when the datafile was acquired it was actually running my standard ramp method.

How could this have happened? Is it possible that if I had changed and saved that method it went through and changed it in all my datafiles?
Has anyone else had problems with the acq.txt files?

cheers
Liz

Can you tell if the acq.txt file is being updated or is it just being copied from one processed file to another?

i can think of 2 things
the report display showing is not to full scale
the method is set to collect only 18.2 minutes of uv. in such case the pump will still run and do the full gradient as expected but you will not see the remaining information since it is not acquired by the method

chemstation is neither CFR or GLP so you can pretty much do everything and have any type of weird errors like these if you are not aware of them

To verify what gradient actual was running, you can overlay the pump-composition to the chromatogram. This will tell you which ramp was used.

sorry, neglected to say I'm using GC-MS chemstation.

How would I be able to determine if and how acq.txt was simply being copied and why would it do that anyway?

Does the method that ends up copied to the data file match the one that is loaded when you start your sequence? I wonder if the "store method with data file" option is bugged and it only references the method loaded when you start, rather that whichever method is used during that particular data file acquistion.

It would have been a standby method I had loaded and saved before the sequence was started but I can check the logfiles.

The weird thing is that my sequence alternates between scan and sim methods, both of which are 18.2 min long and the sim files are OK, the 18.2 min sim method is attached to them. Its the 18.2 scan files that have the 20.87 min method attached to them.

Perhaps I inadvertently changed and saved a method without changing the name and that created a bug?