Chromatography Forum

I've been trying to figure something out and I've just about decided it isn't possible. I have Chemstation on a 5890 with an autoinjector. I run a blank of the solvent I use to dissolve my samples, then a series of samples. I overlay the blank so that I can eliminate all peaks caused by the blank. Chemstation won't allow you to print with overlays, so I'm trying to come up with a way to remove the overlay so that I can print. The only thing I've come up with is to save the event table, reload the sample and apply the event table and integrate. I don't like the idea of saving event tables for every blank I run and having so many files laying around. Is there some way to removet the overlays?

Second question:
The autoinjector will inject a minimum of 1 uL. This doesn't exactly provide the nicest peak shape. Is it possible to set the split high enough to inject neat samples or can it only be used with diluted samples?

Dtahm: Sadly, this is a consequence of Chemstation software. You must reload the event table in order to visually "subtract out" the matrix peaks from the analyte peaks. I believe that TotalChrome software does allow blank chroms to be overlain without reloading an event table each time.

In regards to your sample injection, the highest split ratio setting that instrument can perform is 200:1 no? Or you could do a 1:100 or 1:10 dilution of your neats in water (solvent, matrix blank) and then inject the one microlitre per a 1:100 split---this would give a total "dilution factor" of 1,000 or 10,000. This may solve your problem

I have never tried running a 5890 with Chemstation, so I am not sure if this would work.

Could you not do a Column Compenstion run and then set your signal to subtract the column compensation run?

Gasman

You can use 5ul syringes instead of 10ul. Alternatively, there was a "nanoliter adaptor" that reduced injection volumes by 5? times, eg 1ul=0.2ul. You may be able to find a secondhand or unused one for sale somewhere.

Can't help with your other problem.

I've been trying to figure something out and I've just about decided it isn't possible. I have Chemstation on a 5890 with an autoinjector. I run a blank of the solvent I use to dissolve my samples, then a series of samples. I overlay the blank so that I can eliminate all peaks caused by the blank. Chemstation won't allow you to print with overlays, so I'm trying to come up with a way to remove the overlay so that I can print. The only thing I've come up with is to save the event table, reload the sample and apply the event table and integrate. I don't like the idea of saving event tables for every blank I run and having so many files laying around. Is there some way to removet the overlays?

Can't you use "Subtract Blank Run" to subtract the solvent from your real chromatogram? Make sure under View that yours is on View Full Menu or you won't even see that option. I don't understand what you mean about Chemstation not allowing you to print with overlays, we print from the overlaid format all the time, or I am I missing something?

Second question:
The autoinjector will inject a minimum of 1 uL. This doesn't exactly provide the nicest peak shape. Is it possible to set the split high enough to inject neat samples or can it only be used with diluted samples?

With a 10ul syringe, the minimum is 1 ul. Change the syringe to a 5 ul syringe, and change the syringe configuration under Injector to 5 ul, and you'll get the option of injecting 0.5 ul. We do this all the time to inject 0.5 ul of aqueous samples. And you can do similar by using a 1 ul syringe and changing to 1 ul in the configuration options under Injector. I can look up the part numbers for such 5 ul and 1 ul syringes if need be (but so can you), available from Agilent, Hamilton, and SGE.

It is possible to print overlays from Chemstation but only the chromatogram. Simply overlay the signals, select print selected window and this will work.
Chemstation will not generate a report from this but that can be done individually.



GCguy

Another option for getting the overlays printed is to get the display as you want it, then (depending on your ChemStation version), use the "Copy to Clipboard" feature.

You can then paste the chromatogram into any Windows program for display, editing, and printing.