Method Setup - PDA Method
A new PDA Method tab is available in the Method Setup dialog. The Method Setup - PDA Method dialog can be also accessed using the new Method - PDA Method command in the Instrument window.
Method Setup - PDA Method
Sets the spectral detector for which the particular PDA Method settings will be used in the case that more than one spectral detector is configured on the Instrument.
Restricts the comparison of the spectra only to the wavelength range specified in the From and To fields.
This parameter specifies the section of a peak, expressed as a percentage of the detected peak height, used for peak purity evaluation. It defines the interval where spectra are included in calculations.
Sets whether the calculations of peak purity value will be carried out based on spectra in All peak data points or only Five significant points. These are:
- the peak purity start (located in one-third of the distance between the start point of the interval set by Absorbance Threshold and peak apex)
- the peak purity inflexion point (in two-thirds of the distance between the start point of the interval set by Absorbance Threshold and peak apex)
- the peak apex
- the other peak purity inflexion point (in one-third of the distance between the peak apex and end point of the interval set by Absorbance Threshold)
- the peak purity end (in two-thirds of the distance between the peak apex end point of the interval set by Absorbance Threshold)
With the Use Background Correction checked, the spectra are compared against a corrected baseline. The corrected baseline (background) for individual wavelengths is interpolated between the peak start and peak end points. Calculation details can be found in the chapter "Appendix - Mathematical Formulas".
Note:
Setting the section in the Method Setup - PDA Method dialog causes two things: First, regardless of the settings, the tab is copied to the measured chromatogram. Second, in the case that at least one library is selected, the library search is performed at the moment the acquisition ends and its results are stored in the measured chromatogram. Library compound with the best-matching spectrum is visible in the PDA Best Match Name column of the Result Table, the whole search results can be accessed through printing the report (Report Setup - PDA - Library Search Results - Table/Spectra checkboxes). User can later change the search settings in the measured chromatogram's method (Measurement Conditions - PDA Method tab) and the changes done there are automatically applied to the Result Table and prints. Manual library searches as performed from the PDA Chromatogram window only influence the print of the chromatogram data if the print is invoked directly from the PDA Chromatogram window.
Sets the method of the match factor calculation. Possible options are Least square, Weighted Least Square, and Correlation (calculation details are in the chapter "Appendix - Mathematical Formulas").
Only hits with match factor above the value entered will be displayed.
Limits the number of displayed spectra discovered by matching according to the selected criteria.
The spectra comparison will be limited to the range specified in From and To fields (the whole overlapping range is compared when not checked).
Limits the found spectra only to those with the RT within the range specified in the Relative field (in % of the peak RT).
Use Background Correction
With the Use Background Correction checked, the spectra are measured against a corrected baseline. The corrected baseline (background) for individual wavelengths is interpolated between the peak start and peak end points. Calculation details can be found in the chapter "Appendix - Mathematical Formulas".
Sets the library search for all detected peaks. While unchecked, only the identified peaks are evaluated.