Chromatography Forum

I am setting up a linear pesticide curve in chemstation (GC) containing Permethrin, Tetramethrin, Esfenvalerate, Sumithrin, MGK 264 and Piperonyl Butoxide. I created a method and am getting good separation and linearity (120C for 2 mins, 25C/min to 195, 10C/min to 280, 4.5 min hold; agilent 7890/HP-5 column/FID).

My question concerns the fact that there are two isomer peaks for the pesticide actives, and I cannot get an integration table set up so that it adds the two peaks together, and integrates them properly at the same time. Chemstation either disregards the first peak, or will not pick up the valley between the peaks (it just drops down the baseline, and adds additional area that is not actually part of the peak(s) of interest) While the 'add sum' function gives me the sum of the peaks, when I manipulate with a 'baseline now' or the like, I cant get the sum of the peaks of interest, while they are properly integrated. Basically, I need chemstation to pick up a valley between two close peaks, integrating the peaks seperately, yet adding the area of the seperate peaks when I print out a report.

Yes, I am new to chemstation, coming from turbochrom and empower. Thanks for any help.

Sam

I'm not sure about GC-chemstation, but MS-chemstation (Enviro Quant mode only) will let you set up the two peaks in a calibration table as separate compounds with a specific label in the calibration table under "compound type" (e.g., L1). The label "S" is used for surrogates and "i" denotes internal standards. If you give it an "L#" descriptor you are then given an option to report the sum of the L# group as a separate compound in the Quant Report. This is typically used for PCBs and Pesticides analysis in the Enviro Quant mode using either an MS or ECD detector. It's hard for me to remember all the details because I haven't used Enviro Quant mode for over a year. I don't think it's available in Enhanced mode but I'm not certain.

ty

Oh yeah, Custom reports work well too. Go here to see how to use them...
http://www.chem.agilent.com/en-US/Produ ... abase.aspx

Also call Agilent Customer service and give them your Chemstation Product number (not serial #) so they know which version of chemstation you are using. They might have a quick solution to this issue.

Ty