Chemstation Calibration



SOP 054 - Data Processing - Agilent Chemstation & Thermo Xcalibur Data Reduction Page 3 of 26 1. This method is designed to allow a user to process Organic Base Screen, Organic. We use chemstation B.03.02 and have been quantifying analytes and creating calibration tables using external standards. I would like to switch to using an internal std for quantification, but am not exactly sure how to set that up in chemstation. Currently we are looking at three separate analytes, we make a 5 point calibration. Calibration parameters are not necessary for a test sample. From the File menu, select Report Template and then click Open. From the list of templates, select Area%.rep to generate an Area%report when run the sample 5.11 Create a sequence This button starts the Sequence Wizard that steps you through creation of an acquisition reprocessing sequence.

Some of the feedback I received after my last post was that most of the small environmental labs out there are still running 5971 and 5972 MSDs off the old G1701AA.03 software, and that demonstrating data processing techniques in G1701EA.02 may not be relevant. Fortunately, we still have a 5890/5971 in the lab.

Unfortunately, we are controlling this instrument from an old computer running Windows NT 4.0 and MSD ChemStation G1701BA.00. In order to demonstrate A.03 functionality, I had to run down a working copy of Windows 98 and install it in a virtual computer in Windows 7 because G1701AA.03 requires a 16 bit version of Windows. Officially, HP only supported Windows 95, but Windows 98 Second Edition was an extremely stable OS, and my old lab had good luck running the software on this platform.

Agilent

Today’s tutorial will focus exclusively on the EnviroQuant version of A.03, and will cover populating the calibration table with compounds using a few compounds from the first internal standard group of EPA Method 524.3. We will deal exclusively with the initial calibration menu (InitCal) which is shown below, though “save method” is found under the File menu.

First, you will want to set your calibration’s global parameters, and this is done under the “Set Up Quantitation” menu option. There are a few things worth mentioning here. The default integration parameter file is events.e; you can create specific integration parameters for specific compounds, but you’ll want to enter your default integration file here so you don’t need to type it in for every compound later. The same goes for the rest of information in the New Compound Info box below.

Calibration

Once you are satisfied with your selections for the Quant Database Globals, click enter, and the Edit Compounds dialog box should appear.

Calibration

Click “Insert Above” and this brings up the “Quant Setup” interface (shown below), where you can select peaks by double right clicking them, name them, and select quant and qualifier ions. Personally, I don’t like this interface, and prefer manually entering the compound info. Generally, I deal with large compounds lists (like 8260 or 8270) and find the peak selection process tedious.

If you go back to InitCal menu, and select “Edit Compounds,” the same Edit Compounds dialog box from before appears, but this time, when you click “Insert Above,” you should see the first page of the compound info screen. If you already know the elution order of your compounds, you can enter them one at a time.

EPA Method 524.3 – Table 4 lists the recommended quantitation ion and associated internal standard (IS) for each of the target analytes. Make sure you change the Quant signal to “Target Ion.” If you don’t know what qualifiers to use, you can look up the EI mass spectra at the NIST website.

Chemstation

Generally, when choosing quantitation and qualification ions, you will want to use the M+ molecular ion, the C13 isotope (M+1)+ or halogen isotope (M+2)+, as well as an ion that can be explained by a common mechanism, such as the loss of a ring, halogen, or hydrogen. The mass fragment with the highest response does not always make the best quantitation ion, especially if it has a relatively low m/z (less than 50) because there is commonly high background responses for these ions.

Chemstation Calibration Report

Chemstation Calibration

This is a good stopping point. Next time, we’ll configure internal standards, matrix spike compounds, and surrogates for automated data processing by the quant macro.

Openlab Chemstation Calibration

I am working with Agilent Chemstation and am trying to analyze for 3 compounds. I have created an 8 point calibration curve and have a good linear regression for each compound. My calibration curve ranges from 0.05 ug/ml to 10.0 ug/ml. When I go to reprocess my calibration curve for 0.05 and 1.0 ug/ml I receive amounts such as 0.00 for the first compound, 2.3e-3 for the second and 3.4e-1 for the third compound at standard 0.05 and for 1.0 ug/ml I receive 1.1e-3 for the first compound 2.4e-2 for the second and 3.4e-1. At first I thought maybe I should recalibrate or make a new curve but when I do the first two cal points (0.05 and 1.0) and then go back to the first cal-point 0.05 I get the results (5.5e-2 5.4e-2) that I am looking for. Another frustraiting issue is that samples that are in the middle of my cal-range (1.0 ug/ml) come as expected. Also when I go to calculate other samples at 0.10 concentration the area is the same as my standard in the calibration curve (44.372) but the concentration amounts are not the same. Any clues as to how I might be able to fix this?