peak integration limits

[madalinus]

Hello to everyone!

Is there a way in the Clarity software to define in the method the peak integration limits? I want to compare the MWD of various samples and I want to force the program to integrate the peaks of the various chromatograms in between specific values (that are the same for all chromatograms).

Thank you,
Madalina.

[Daniel Mentlik]

Dear Madalina,
If I get it correctly, you want only a certain part of the chromatogram to be integrated. That is actually quite easy to achieve - here is how to achieve it:

• Open a measured chromatogram in the Chromatogram window and use the Chromatogram - Integration - Integration Interval command. You will be prompted to select the interval where peaks should be integrated.
• Let's say I want only peaks between 21 minutes and 35 minutes integrated - so I selected the interval approximately on these limits. The integration of the given chromatogram will be limited to the area.
• On the bottom side part of the Chromatogram window, look at the Integration tab. You will notice an Integration table, which is the same as in the Method Setup - Integration dialog. This table was copied from the method when the chromatogram was created and then is valid only for a given chromatogram.
• Notice a last line in the Integration table - it should be Integration Interval with two values denoting the beginning of the interval and the end of the interval. You can manually change the times for both values to amend the time to a state you want.
• Now, to make the integration interval being counted for all new chromatograms measured according to the given method - Open the Method Setup - Integration dialog from the Instrument window. Fill in the same row as was shown in the Chromatogram window - select the Integration Interval item in a first unused row and change the times available for the row to whatever times you want. Save the method. Any new chromatograms measured according to the changed method in the future will have the integration limited to the set interval.

Please, see the attached picture of the Chromatogram window to show how does the limited integration and the chromatogram integration table look and let me know if this is the result you want to achieve. Note that you may simply combine several integration intervals in the same chromatogram to allow the integration only on a few separate parts of the chromatogram.

Best Regards,
Daniel Mentlik

[madalinus]

Dear Daniel,

Thanks for the help. I tried what you told me and it is indeed what I wanted. I can change the integration interval for each chromatogram and also define it in the method. The only problem is that as I aquired these chromatograms with the old method in which I didn't define the integration interval, now I have to change manually in each of them the interval in order to apply the changes.

All the best,
Madalina.

[Daniel Mentlik]

Dear Madalina,
actually, even with that Clarity can help you. Supposing you have Clarity station (not Clarity Lite where the option is not present), open the Instrument window and open the updated method in it (the method with the Integration Interval parameter added to the Integration table). Then, use the Analysis - Batch command from the menu to open the Batch dialog. See the attached picture for more details.

In the left part of the dialog, all chromatograms saved in the current project's Data subdirectory are listed. Select all that should be reprocessed (with the multiselection using the Shift and Ctrl buttons, as usual), then check the first checkbox on the right (Reprocess by Instrument Method). Hit the Proceed button to reprocess all selected chromatograms.

Now, all selected chromatograms will behave like as if they were measured according to the updated method.

The Batch dialog allows more options, for example automatical report of large number of chromatograms at once, and all of these options are described in the Reference Guide and the online help (while you are in the Batch dialog, hit the F1 key on the keyboard or the Help button in the dialog to access the reference description of all of the functions).

Note that all of the manual changes to the chromatograms (e.g. shifting beginnings/ends of the peaks manually etc.) will be lost during the reprocess. Also, if you have used the same calibration file for a long time and only recalibrated it during the course of the time, you would have even older chromatograms reprocessed with the newest available version of the calibration, which will influence results of the chromatograms. Opening the chromatograms with the stored calibration is a solution here - check the Open with calibration selectbox description in the Batch dialog help if you also select the Open Chromatogram Window item.

Best Regards,
Daniel Mentlik

[madalinus]

Hello,

Is it possible to save a new project directory on a removable media? When I try to create a project, it is saved automatically in the Clarity directory and then I have to copy all my chromatograms in this directory from my flash memory. I should mention that I use Clarity installed in the lab computer to acquire the data and Clarity offline installed on another computer to analyse the data.

[Daniel Mentlik]

Yes, this is possible via the Directories dialog.
In the main Clarity window, use the System - Directories... command. A dialog will emerge, where you can set the project directories for various Clarity Instruments. For your offline version, if you want to sometimes evaluate the chromatograms from your flash disc and sometimes from your local disc, it would be wise to prepare more than one instrument in the Configuration of the Offline version, and assign different project directories to them (the first could be, for example, left as it is, while the second instrument may have the path to the project directed to the flash disc). Uncheck the All as Instrument 1 checkbox for this purpose.
Note that applying the changes to a selected directory outside of Clarity main directory will cause the creation of Projects and Common sub-directories in the selected directory. Any project with data saved on the flash disc will have to have the complementally named *.prj file saved in the Projects subdirectory - copy it from the Projects subdirectory of the Clarity station used for the measurement.