In the following procedure, you will find steps to create a multipoint ESTD calibration method with OpenLab CDS 2.X.
Steps to follow:
1. Load the Data
a. From Data Selection view click Load Data, or from Data Processing interface click Open Data. When the Create New Processing Method dialog box opens, select a method configured with Calibration feature based on your application. The Create New Processing Method dialog box will not pop up if the data has linked a method. In this example, we chose GC/LC Quantitative for demonstration, then click Link only (see Figure 1).
In the preceding step, we loaded data and linked this data with the default method. If you want to rename the method or create a method for the loaded data, please see the following step b.
b. In Data Processing view, select the Processing tab and click New Method. When the Create New Processing Method dialog box opens, select GC/LC Quantitative (or another method configured with the Calibration feature) and click Create method. This default method cannot be overwritten, so click Save Method > Save Method As and save it with a unique name. Select all injections (select the first injection, then hold the Shift key and click the last injection) and click the method saved in the previous step, then right-click and select Link selected injections to selected method. For more details, please see the following video (see Figure 2):
2. Edit processing method
Optimized data integration parameters are critical for quantitative result accuracy. The video shown in Figure 3 demonstrates the following steps a to d on how to optimize peak integration:
a. Switch to Home tab and click Processing Method view from the windows section of the menu bar.
b. Choose the lowest concentration calibration sample data. Set the desired integration parameters according to the chromatogram.
In this example, we do not want to quantify the small peak around 8 minutes. In the integration table, Slope sensitivity is changed to 2, Area reject value changed to 15 (according to the area of the peak we do not want to quantitate). Add Integration Off at 0 minutes. Add Integration On at 2.5 minutes. The later action turns off the integration from 0 to 2.5 minutes. Then add another Integration off at 9.5 minutes, turn off integration after 9.5 minutes.
c. Click the Home tab and select Peak Details from the windows menu bar. Check if integration is correct for all injections. If the integration needs optimization, see the previous step to modify integration parameters again.
d. Click Reprocess All.
The video shown in Figure 4 demonstrates the following steps e to i on how to set up calibration parameters.
e. Focus on the lowest concentration calibration sample data. In the Chromatograms dialog box, click the first hollow triangle on top of the peak (it will change to a filled triangle). Hold the Shift key and click the triangle on top of the last peak to select all the integrated peaks in the chromatogram. Right-click any of the selected peaks and select Add multiple peaks as compounds to method in the context menu.
f. Click Processing Method > Compounds > Identification > Compound Table, then give each added compound a name. Keep the default values of all the other parameters in this table.
g. Click Processing Method > Compounds > Calibration > Compound Table and enter the desired values for each column: Amount Unit, Concentration Unit, Response, Mode, Origin, Multiplier (if necessary), and the concentration for each compound per level. You can use Fill Down to quickly fill the columns if the values are the same for that column. In this example, we are going to create a three level calibration curve and each level has two paralleled injections.
h. On the General tab, change Curve calculation to From individual calibration points (choose the proper Curve Calculation mode based on your application) and set the number of levels for the calibration curve (three levels in this example).
- From average per level: Amounts and responses of all calibration points contributing to a level will be averaged and used in the algorithm to calculate the best calibration curve.
- From individual calibration points: All amounts and responses of the individual calibration points will be used directly to determine the calibration curve.
i. Select the report template in Reports > Injection Report, then save the Processing Method.
3. Check and edit injection list:
Click Injection List from the windows menu bar of Home tab. Set sample type and levels in Level Column; choose the Run type Clear all calibration in the first calibration line (to clear all historical points at all levels, and avoid averaging the old curve result with the new one). Enter Multipliers, Dilutions that apply to your analysis. In this example, enter the following values from Sample 1 to 4 in the Multiplier and Dil. factor columns (see Figure 5).
4. Reprocess data
Click Reprocess All, it will update calibration information and process the sample data in the injection list. Click Calibration curve from the windows menu bar, your calibration curve should look like the following picture (see Figure 6):
Navigate to one of the sample injections, bring in the Injection Results dialog box, you should get the results as shown in Figure 7. Save the results.