Keep in mind that:

• The calibration curve and equation will not be displayed, if the equation could not be constructed using all the points marked as used. Please check that you have entered retention times and molecular weights for all points to be used in the calibration.
• Calibration curve is cut off on nearest local extreme outside the Minimum RT and Maximum RT to assure it is monotonous on definition interval. Definition interval is checked during all computations.
• If local extreme occurs between the Minimum RT and Maximum RT, Invalid points to construct curve error will be reported. Check the correctness of your data (typing mistake in Mp value is a typical problem) or decrease the polynomial fit degree.
• The last Broad Peak is temporarily remembered and used in subsequent recalculations. Current Broad Peak is indicated in lower-right corner of the Calibration window.
• The Universal Calibration cannot be used for Broad On Narrow because computed K and Alpha values will be overwritten by K and Alpha of the unknown sample. If you know K and Alpha of the unknown sample, use Narrow Universal Calibration.
• When Broad On Narrow calibration type is used, the K and Alpha values fields in the Chromatogram - GPC Results tab are inactive, because these values are loaded from the calibration results.