Chromatography Forum

I ama young scientist and a new Totalchrom user, and I am struggling with how to go about creating a custom expression to automatically calculate wt./wt.% assay. I understand how to add custom expressions in a report format. As of right now I am setting my reference standard calibration level to "1", and added in the amount of standard used. In my sequence my first reference standard is set to "cal-replace" and the next four are set to "cal-average". I have added sample amounts into the sequence, and understand that the method will have to be calibrated to the working standards each time it has run.

In the past, I was told to use the following expression:
(#RA/#WT) x 100

It was explained to me that raw amount, in totalchrom terms:
area sample/wt.standard x area standard

Unfortunately, my weight percent values do not appear to be correct. Has anyone else had success calculation weight percents using totalchrom?

Any help is sincerely appreciated.

Looks like this is an old question that went unanswered. But I'll take a stab.

My analysis requires the use of a %solid. A 98% solid sample indicates that 2% of the samples weight was water. To account for that 2% of water weight in our "final results" I enter 0.98 into the "sample amt" column of my sequence. You should notice the adjustment in your "raw amount" vs. "adjusted amount".

Hope this helps.