Frequently Asked Questions

ChromGenius

Q: How is the peak width of a predicted peak calculated in ChromGenius?

A: If there are no experimental peaks in the ChromGenius database with a defined width, then the width is calculated according to the following formula:

Width = 4 * (tR(calc)/PlateNumber2)

If there are up to 3 peaks found in the database with defined experimental widths, then the width of the predicted peak is calculated as a mean from these experimental widths.

However, if there are more than 3 peaks found in the database with experimental widths, then the width of the predicted peak is calculated on the basis of that experimental data.

Q: How do I merge two databases?

A: Here is a workaround (for records with one structure only):

Let’s consider two databases: A.cgb with its methods and B.cgb with Method1 and Method2. We will merge all data from B.cgb into A.cgb.

  1. Open B.cgb.
  2. Navigate to Method1 in the field with method names. You retrieved all records for this method in list A.
  3. From the Record menu, choose Export Parameters, and save the file as Method1.pa.
  4. From the Database menu, point to Prediction Accuracy, and then choose Estimate.
  5. In the dialog box that appears, select Method1. Select the Place Results to SDfile After Estimation check box and specify the location and name of the SDFile (Metod1Structures.sdf).
  6. Click Estimate to start the process.
  7. Open the second database, A.cgb.
  8. From the Database menu, point to Tools, and then choose Import. Input the Method1structures.sdf file and attach the parameters from Method1.pa as usual. Specify to get the structure name from the header.

Do the same steps for each method.

Q: After running the training set, we obtained the graph of calculated vs. predicted but would like to display the equation used for the prediction. Is there a possibility to have this equation displayed somewhere or have access to the equation?

A: In ChromGenius, when you obtain the results for one structure or for the mixture, the prediction equation (along with standard deviation and correlation coefficient) is populated into the Method Parameters subwindow. On the General Toolbar you can click the Equation button and change settings for the equation. After making the changes, click the Recalculate (a thunder sign) button to apply these changes.