In TargetLynx, the low concentration peaks are blank - WKB3501

SYMPTOMS

• After processing standards in TargetLynx, the low concentration standards are blank
• The peaks are integrated and there are area counts in the table, but no concentration

ENVIRONMENT

• TargetLynx
• MassLynx 4.1

CAUSE

• The y-intercept for the calibration curve is larger than the calculated concentration for the low concentration or blank concentration samples
• This indicates a negative concentration, so the software leaves the concentration blank

FIX or WORKAROUND

1. Right-click the results table in TargetLynx and select change column order.
2. Locate Primary Flags. If it is on the left, select it and click Add. If it is already in the right window, click OK.
3. The primary flag for the blank concentration samples includes a bbl notification that identifies this issue.
4. You can force the origin through zero, but this may cause the R2 and resulting concentration values to be further off.
5. To edit the TargetLynx method, go to Calibration Properties .
6. Change the calibration origin to zero and save the method.
7. Reprocess the data and confirm that the R2 improved and the concentrations are closer to the expected values.
8. The missing concentrations should now be present.

ADDITIONAL INFORMATION

If the R2 is not improved and the concentrations are farther from the expected values, either the curve type (linear vs. quadratic, and so on) is incorrect, or there are peaks throwing off the linear regression of the curve. Try excluding these peaks.