GC Image Users' Guide

Quantification

Quantification often is based on calibration, i.e., measurements of known quantities to establish a quantitative scale for subsequent measurements of unknown quantities. GC Image has tools for creating calibration tables from batches of processed chromatograms with measurements of known quantities of multiple analytes and for using those tables to provide quantification of analytes in subsequent chromatograms. Several types of quantitative reports are described in Reports.

Calibration Tables

GC Project can extract a Calibration Table from a batch and export it to a file, where it can be referenced from individual images for calibrating amounts in the blob table. As described in Projects, GC Project automatically sets the calibration table reference in images through the Process Runs and Auto Process dialogs. Calibration Table references in images also can be set manually in GC Image.

To generate a Calibration Table file, select "Actions -> Calibration Table". In the Export Calibration Table dialog, shown in Figure 8, select the batch and click "OK". Then, indicate the desired file name and the file format (CSV or XML). To build the Calibration Table, GC Project extracts all blobs of each image listed in that image's Composition Table. For each blob, GC Project records in the Calibration Table: Compound Name, Response (i.e., Volume), Amount (from the Composition Table), and source image name.

Figure 8: The Export Calibration Table dialog.

Clicking "OK" launches the save dialog for specifying the file name, shown in Figure 9. The table is saved to the project's Processing folder.

Figure 9: The Save Calibration Table dialog.

Amount Units

The software allows users to indicate the unit of measurement for calibrated amounts. The unit can be specified as the default for the software, specified for an image, or specified for a project. When a report is generated, the specified unit of measurement will be reported for the amount column.

• Specify the default unit
  The user can specify a default unit to be used by the software.
  1. Go to Menu: Configuration -> Configure Settings.
  2. Choose Blob Statistics, as shown in Figure 10.
  3. Under Calibration Amount Unit, enter the default unit.
  4. To always use this unit when no unit is specified in an image or a project, check the checkbox provided.
  5. Click OK to apply.

  Figure 10: The Blob Statistics dialog.

• Specify the unit for an image
  The user can specify a unit for a specific image if the image is not a part of a project. This unit will be applied to the amount table, the calibration table, and the reports. When an image is open,
  1. Go to Menu: Configure Amount Table.
  2. In the Amount Table, enter the unit in the Amount Unit field, as shown in Figure 11.
  3. Click OK to apply.

  Figure 11: The Amount Unit textbox in an image Amount Table.

• Specify the unit for a project
  The user can specify a unit for a project. This unit will be applied to all vials and images of the project. When a project is open:
  1. Select the Vials node.
  2. Choose the Amount Table tab, as shown in Figure 12.
  3. Click on Edit at the right of the Amount Unit field.
  4. Enter the unit.
  5. Click OK to apply.

  Figure 12: The Amount Unit textbox in the Vials Amount Table.

Contents Previous: GC Project Wizard Next: Reports

GC Image™ Users' Guide © 2001–2010 by GC Image, LLC, and the University of Nebraska.