about reprocessing copy in GC 7890

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wildroseGC
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about reprocessing copy in GC 7890

Hi,
      my instrument is GC 7890. When i used GC6890, i can use snapshot to see the peak  on offline when the sample is running, but for 7890, there is reprocessing copy, the same function as snapshot. I don't know how to use it, cause most time it's very useful for me.
       can anyone tell me how to use it ?( i read the help, but didn't describe how to use, just describe the function  that we could use)
        thank you
        rebecca

Dr. Analytical
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In the newer versions of

In the newer versions of ChemStation, the Snapshot feature is only available in the Offline (Reprocessing) mode.  When you are collecting data, switch to the Offline copy and choose File, Snapshot, and the chromatogram will appear.

If you are not collecting data, then there is no Snapshot file.

These instructions are for the GC ChemStation, not the GC-MS version.

wildroseGC
wildroseGC's picture
Hi, Dr.Analytical

Hi, Dr.Analytical
          thank you for answering my question. I will try again to see how's going.
          by the way, can i ask you another question about sample preparing? When i prepare PAH water sample, according to my company SOP, i need add 10N NaOH to make ph higher or equal to 12. I just wonder why water sample need ph higher or equal to 12, and soil sample doesn't need adjust ph?
     water sampler is stored in 250ml glass amber, and soil in the 44ml glass vial, which weight within 10 to 12g, and put acetone with surrogate.
       thank you so much

Dr. Analytical
Dr. Analytical's picture
A pH adjustment of a water

A pH adjustment of a water sample is usually performed before extraction with an organic solvent (either, hexane, ethyl acetate, etc.).

At a high pH, any acidic compounds (i.e., compounds with a -COOH and sometimes -OH) react with the base to form the conjugate base (-COO- or -O- ).  These ionic compounds are usually not soluble in the organic solvent, so they remain in the water. Neutral compounds, the the PAHs, and neutral bases will be extracted.  This is a common procedure for fractionating samples by compound class.

In a similar manner, you could acidify the solution to pH < 2 and then the extraction would remove the neutrals and acids, and leave the bases in solution.

wildroseGC
wildroseGC's picture
Hi, Dr. Analytical

Hi, Dr. Analytical
         thank you so much to give me the very useful knowlodge and i totally understand the reasons.
For the question of reprocessing copy, i tried to use in 7890GC-FID. I open it on offline, Can you tell me how to use it ,then when the sample is still running, i can use reprocessing copy to check on offline?( the same function of snapshopt, i know how to use sanpshot, but not reprocessing copy)
         thanks again
        rebecca 

Dr. Analytical
Dr. Analytical's picture
Rebecca:

Rebecca:
The "Offline" and "Reprocessing Copy" are the same program.  Offline is the name on the desktop, but you choose Reprocessing Copy from inside an Online session.

The Offline session allows you to use all the Data Analysis features of the ChemStation.  On the newer versions of ChemStation (B.02 and later), you can not use Data Analysis in the Online version while the GC is running.  You must use the Offline mode.

Does this answer your question?
 

wildroseGC
wildroseGC's picture
Hi, Dr.Analytical

Hi, Dr.Analytical
         maybe my english has some problems, i am sorry. I use an example to demenstrate my question.
In online, there is running a sample with surrogate, i want to know if the surrogate is good or not, then i want to use reprocessing copy to see this running sample in offline.But i don't know how
In the 6890GC, i open snapshot on offline, then i click the running sample on online, then i can get chrom on offline.
    That's why i ask cause i don't know how to use reprocessing copy to see the running sample
      can you understand what's my meaning?
      thank you so much
      rebecca chen

Dr. Analytical
Dr. Analytical's picture
rebecca:

rebecca:
What version of ChemStation are you using?  Is this GC or GC-MS?

In the GC version, go to the Reprocessing Copy and click File, then there should be an option for Snapshot.  That should load the current run.  You should also load your method in this copy, so that you can review the data.

If you have the GC-MS version, then I can not help you.

wildroseGC
wildroseGC's picture
Hi, Dr.Analytical

Hi, Dr.Analytical
        yes, my instrument is GCFID 7890.
You said  go to the Reprocessing copy, this is folder or in the offline? Every time i click reprocessing copy in offline, the system said it's already running.
       Sorry to bother you again, cause i tried today, but i still didn't sucess. Could you please tell me more detail? i appreciate that,
       thanks a lot
      rebecca

Dr. Analytical
Dr. Analytical's picture
Rebecca:

Rebecca:
Remember that "Offline" and "Reprocessing Copy" mean the same program.

In the Offline program, click the "View" option on the Menu LIne and look at the bottom option.  It should be either "Full Menu" or "Short Menu."  If it is "Full Menu" then click on that option.  (This choice means "Go To Full Menu" settings.)  Now you should see the Snapshot option under the File menu.

If you are using the "Short Menu" some of the options are not available.  You need to switch to Full Menu.

I hope this solves your problem.