How to calculate the recovery factor

How to prepare for the quantitation

The table below briefly describes how to prepare for the quantitation.

Step

Action

1

Prepare a quantitation table for the components of interest.

Note: An external standard quantitation must be used. Internal standard quantitation tables cannot be used.

2

Perform a sample run with the unspiked sample and a run with the spiked sample.

3

Peak integrate the sample curves to produce the peak tables for the unspiked and the spiked samples.

Note: The sample curves must use the same X-axis base unit as the standards during the integration. Time is the recommended unit for highest reliability.

4

  • Check that the integration is correct.

  • Optimize the integration if necessary.

5

  • Open one of the sample result files.

  • Use File:Open:Peak Tables to copy the other peak table to that result file.

6

Select File:Save to save the result.

How to calculate the recovery

The table below describes how to calculate the recovery factor.

Step

Action

1

Select Quantitate:Calculate Recovery.

Result: The Calculate Recovery Factor dialog box opens.

2

  • Select Global or Personal quantitation tables.

  • Select a quantitation table on the Quantitation table droplist.

Note: Only external standard quantitation tables will be shown.

  • Select the chromatogram that contains the unspiked sample peak table on the Source chromatogram droplist.

  • Select the unspiked sample peak table from the Peak table(s) list to the left.

3

  • Repeat step 2 to select the peak table for the spiked sample on the Addition chromatogram fields.

  • Select the component that was added prior to the sample preparation on the Addition component droplist.

  • Type the injected amount of this component in the Added amount field.

  • Click the OK button.

How to view the recovery factor calculation results

The recovery factor calculated by the software is placed at the bottom of the peak table in the Evaluation module. You need to scroll to the end of the table to see it.

Note: The checkbox Do not show global peak table data must be de-selected in the Peak Table tab of the Chromatogram Layout dialog box.

If the recovery cannot be calculated

If the recovery cannot be calculated, one of the following signs is shown in the peak table Amount column:

Sign

Function

>

This means that one of the amounts/concentrations is higher than the highest value in the calibration curve, i.e. outside the valid range of the calibration curve.

<

This means that one of the amounts/concentrations is lower than the lowest value in the calibration curve, i.e. outside the valid range of the calibration curve.

-

This means that the recovery factor cannot be calculated. For example, this sign might indicate that the peak could not be identified in both runs.

2005-06-15