We are returning the Technical Tip of the Month feature for 2010.
This year's topics will deal mostly with data interpretation.

TODAY'S LESSON: USING ENVIROQUANT (Part 1)

Firstly, what is Enviroquant? Enviroquant is a set of macros (Hewlett Packard/Agilent programs- or more specifically a list of commands) designed to automate environmental analyses. Purchasers of the Agilent Chemstation who do not perform environmental analyses often times skip loading the Enviroquant module entirely. If Enviroquant is set up optimally (I love the word "optimize" and all its derivatives), it will help the analyst quantitate faster and more accurately as well as assist in qualitative analysis. This will free up the analyst to perform the interpretive work.

LOADING THE METHOD YOU WANT ALL THE TIME

OK- let's assume you've opened up EDA (Environmental Data Analysis) by double clicking the EDA icon. You have the choice of either have the last method that was accessed loaded or some other default method that will load all the time. To have the last method that was accessed loaded proceed as follows: File\EDA Configuration...brings up a dialog box and you click "Autoload Method/Data file". Thus, when you open EDA it will automatically load the last method and the last data file that was accessed. If you want some other default method that will load all the time then you have to single right click the EDA icon on your desktop. Then left click "Properties". Look in the box labeled "target". You will see in that command line something like the following: C:\HPCHEM\MSEXE\MSDA.EXE 1 ,envorphinit `C:\HPCHEM\1\methods\envdef.m', envinit.mac.

Replace whatever file is listed with the .m (stands for method) with the method you want. For example, if you always process using method called ecsbna2.m, then replace just that portion in the runstring as follows: C:\HPCHEM\MSEXE\MSDA.EXE 1 ,envorphinit `C:\HPCHEM\1\methods\ecsbna2.m', envinit.mac .

WHAT TO DO IF THE Y AXIS SCALE IS NOT LEGIBLE

On some systems, when you draw a total ion chromatogram, the Y axis will sometimes be truncated because the default font in the Agilent software does not fit properly on the screen. To remedy this, you need to change the font. In the command line (the command line is the white space just below the lime green strip at the bottom of the screen) type the following FONTAXIS="COURIER".

The word COURIER should appear in the lime green bar to indicate that Courier is now the font being used. Then click Int\Draw Chromatogram and it will redraw the chromatogram using the courier font which fits nicely on the screen. Your graphics printouts will also have the courier font. During your data processing the font may revert to the default, so simply type the above command and redraw the chromatogram and you will correct the problem. After you type FONTAXIS="COURIER" in the command line, you can highlight it by clicking and dragging then hitting CNTL + C (control C which means copy) then rather than re-typing FONTAXIS="COURIER" you can hit CNTL + V (control V which means paste).

UNDERSTANDING THE RTE INTEGRATION PARAMETERS

One of the most useful features of Enviroquant is that if the integration parameters and other settings which we will discuss in this seminar are optimized, the software can quantitate and properly identify every analyte on your target list with no manual integrations necessary. In fact, when I set up mass spec methods during my consulting, I won't rest until every compound in all 5 points can be integrated and properly identified without any manual integrations or # signs.

The # signs mean that the ion qualifiers are out of specification.

The first thing you have to do is set the default integration settings in RTEINT.P. In a future lesson I'll show you how to make every compound specify that integration file (or any other file you desire).

Click on click Int\Integration Parameters and it will open a dialog box like the one below:




Settings that Ferry considers essential:

Data point sampling. You see the number 1 in the above box. That means the system will include every point when integrating. If a number 2 were entered, it would use every second point when integrating. I use a setting of 1 for this parameter because in my experience it has been the most reliable.

Smoothing: When checked, a smoothing algorithm is applied to help improve the ability to integrate the whole peak. I always activate the smoothing feature because in my experience it does indeed help to improve the integration.

Detection filtering. It can be set to 5 point, 7 point or 9 point. The lower the point setting the more likely the system is to separate shouldered and unresolved peaks into two separate peaks rather than one larger peak. I use a setting of 5 point for this parameter because in my experience the other 2 settings seldom integrate the way I want it to integrate.

Start Threshold. It's also called the slope sensitivity. The range is from 0.001 to 100. The default is 0.200. This is a throwback to the old RTE days and like the Detection Filtering setting it is used to separate shouldered and unresolved peaks into two separate peaks rather than one larger peak. I have found two settings very useful:

0.200   often separates shouldered and unresolved peaks into two separate peaks
0.020   often integrates shouldered and unresolved peaks as one peak

Obviously with a range of 0.001 to 100 we could spend all year discussing the options but the 0.200 or 0.020 choices have worked well for me in the past.

Stop Threshold. The range is from 0 to 100. The default is 0. The larger the number, the more efficient the integration routine is in picking up area at the end of a tailing peak. If your peaks are gaussian (symmetrical) then set it to 0. If you have a few peaks that tail a setting of 10 often works and you can write a custom integration file with a large Stop Threshold just for those peaks.

Minimum peak area. I see no sense in using the "% of largest peak" setting". Instead, look at your low level standard areas and pick and area count setting commensurate with that.

I suggest leaving the baseline allocation settings set to the default.

In the next lesson scheduled for April, we'll continue our discussion on Enviroquant.

If you have any questions about this application please
feel free to e-mail Mark Ferry by clicking here:

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