Chemstation Report NORM% results (and Mol% vs. Vol%)

[Labgurl]

Can anyone help me out please.
I'm working with Chemstation methods that were created by someone else.....and the reports read Norm% values. Is it possible to customize the report to read wt%, mol% or vol%?

Our Standard method and Sample method are identical (except the response factor from the standard method has been applied to the sample method.)

Our standard certificate results are measured in volume%. So it was those certified values that were entered into the Standard method, and the response factors from the standard run were used in the creation of the sample method. The certified volume% values match the report Norm% values for our standard runs. Now is it safe to say that the Norm% values obtained from the sample runs would then too also be vol%?

I tried running a different standard which certified results were given in mol%, and the Norm% report values did not come close to matching.
The standard is a 8 component Liquid mix piston cylinder (methane to pentane & C6+ Balance). The samples are unknown volatile liquid mixtures of these components.

Any suggestions?

[Consumer Products Guy]

Is it possible to customize the report to read wt%, mol% or vol%?

Disclaimer: I only use ChemStation up to A.10.

We use Sequence Summary Reports to deliver our results in weight percent (usually) or in v/v%, depending on how we set up the Sequence Table. We use "ESTD%" under Specify Reports, and set up a calibration table from an injection of our standard, then Save the Method. Most of the remainder is handled under sequence, like in Sequence Table and in Sequence Output (select box 9 and use "Compound Summary").

[Labgurl]

Ok, we had a newer version of Chemstation installed Jan/09, so I think it's pretty up to date.

Ok so for your set-up....do you just use one method....the same to run the standard (external std) as you would with your samples? You don't apply any response factors from your standard run?

[Consumer Products Guy]

Ok, we had a newer version of Chemstation installed Jan/09, so I think it's pretty up to date.

Ok so for your set-up....do you just use one method....the same to run the standard (external std) as you would with your samples? You don't apply any response factors from your standard run?

Yes, one Method used for both external standard (or internal standard) as for samples. We establish linearity (virtually all are linear in our working range). In Sequence Table (ST), the external standard (ES) is run on first Line as Calibration Standard, Replace, with no update of retention time. The Amount, Multiplier, and Dilution cells are left blank. Second Line is same vial, several injections, same but as Average, again no update of retention time. Third line is where samples begin, same Method listing. What we do is enter sample weight in grams into "Amount" and the ml which that's diluted to in the Dilution column; if there's an additional dilution we add that to the multiplier column (for example, an additional 1 to 10 dilution gets entered as "10" because it's now 10 times more dilute).

All following can be set up either before or after the sequence is injected. In Data Analysis, the external standard is run and integrated (this can be before the sequence is started or use one of the ES injections). This is thenintegrated properly; we usually set up the integration to only integrate the peak(s) of interest. Then a NEW Calibration table is set up. We enter the ES concentration in grams/ml into the "Amount" column, then hit Enter, and save the Method. Then go back to Sequence, set up as in my earlier post for Sequence Output, change Sequence Parameters to "Reprocessing Only" and check the box to the left of that (important), then hit Run Sequence or Partial Sequence.

All the data stuff, calibrations, etc., can be done either before or after the injections, inlcuding modifying the Method and reprocessing. I am definitely NOT a computer guy, and I find ChemStation pretty logical. It's way easier than uploading a photo to this board !!!

[GasMan]

If your calibration mixture is in Vol%, ChemStation can not change the report to Mol% without the use of macros. Moving between Vol%, Mol% and Wt% involves calculations using molecular weights and compression factors for the gases.

Gasman

[Labgurl]

thank-you for your responses.

I knew there would be calculations involved for changing from vol%, mol% and wt%, I just thought you may be able to add the relevent information into Chemstation and have it calculated & reported.

K....last question.....in our "Amount" column it reads (Mol%) where the std vol% were entered from the certificate of anaylsis values.
And when we run the standard, the component Norm% values we get match the certificate values.

Can the "Amount" column heading maybe just be renamed? That's probably where our confusion is coming from?! I hope.

[GasMan]

Labgurl,

If you go to the Data Aanalysis screen, click on "Calibration" in the menu bar, then click on "Calibration Settings", you will get a window appear where you can add an entry to the 'Amount Units' box. This will change the heading in the report.

If you need macros (free) to give you reports in Mol%, Vol% and Wt% and other gas calculations, contact me by email.

Gasman

[adeputy]

To do the calculations, you can either enter a multiplier in the calibration table or into each line of the sequence table. The column "dilution factor" in sequence table is also a multiplier.

[Labgurl]

Ok...now I have another question. Our results are being challanged. Everything points confirming that our results are in vol%. Our standard is certified in Vol% and the results check out great. We use a separate method for the standard only because it is in a piston cylinder and is comprised of methane, ethane, propane, iso-butane, n-butane, iso-pentane, n-pentane and the remainder is C6+ (a back flush that lumps C6 and beyong together). The standard method has a separte injection port to accomodate the piston cylinder, but otherwise the standard enters into the inlet and the remaining system the same as our samples. Our sample method is auto-injected 2uL (we've also tried injecting 1uL and because results are in %, there is no difference).

We calibrate using the certified standard, and use those response factors for each component in the sample method to measure the sample component peaks.

We do not use an internal standard for sample prep. Sample prep is simply filling a vial (capped) with no headspace. It's staight sample, and each sample consists of the same matrix, just varied concentrations.

Basically my question is.....Is there anywhere in Chemstation where I can check out the calculation for results to see if there are any differences in the methods that I'm not catching when I print out the entire methods?

Are there liquid standards out there (vials) for methane, ethane, propane, iso-butane, n-butane, iso-pentane & n-pentane?

Any input is greatly appreaciated!