DHA Settings
In this pane, you can set up the DHA Method - choose a norm and edit its parameters.
Chromatogram window - DHA - DHA Settings
Displays the currently opened DHA Method. All settings in the DHA Method are saved in the *.DHA file, which is independent on the method opened from the Instrument window. The last opened DHA Method used in the Chromatogram window is saved in the project file (for more details, see also the chapter (for more details see also chapter Project)).
New
Creates a new DHA Method with default settings.
Open
Opens the Open DHA Method dialog where you can select the DHA Method you want to use.
Save
Saves the settings of the current DHA Method.
Save As…
Opens the Save DHA Method As dialog for saving the DHA Method into a new file.
Select the norm you want to use for your calculations.
Caution:
Based on the purchased DHA Extension type, you may be able to select only some of the norms from the drop-down menu. For more information, see the chapter the chapter "Specification"
In the case you select a norm you have not purchased, an error dialog is displayed:
Error when selecting a non-available norm
By clicking on the link, you can display the help containing the conditions valid to each norm.
Selects the units used in the DHA Group Results.
By clicking this button, the Create DHA Calibration dialog is displayed. It allows you to create a DHA Calibration and display it in the Calibration window.
In the Calibration, the peak detection must be set to one signal only; otherwise there will be warnings in DHA Results.
In situations, when the Compound Names in norms are different from names set in the calibration, you can use the Link Table to link those compound names to ensure that all compounds are included in the calculations. For more details see also chapter Link Table
Opens the Link Table dialog, where you can create and edit links between compound names in calibrations and norms.
Chromatogram ③
This parameter defines the column dead time in minutes. This field corresponds to the same field in the Performance tab.
When creating a DHA Calibration from a DHA standard, it is necessary to fill in here the Unretained Peak Time (which is usually the retention time of methane).
Caution:
Retention Indexes can be calculated either with or without the Unretained Peak Time. This depends on the selection of the Retention Indexes use Log. Interpolation with Unretained Peak option in the Calibration Options. For DHA calculations, this option should be checked (default setting), so that logarithmic interpolation with unretained peak time is used for calculation of Retention Indexes. When this option is not checked, the indexes are calculated using linear interpolation.
This parameter defines the value in % of compounds which are undetected in the DHA Results - column % Weight (% Volume is calculated from the % Weight column). The total weight of the detected compounds will be calculated as: 100-(Undetected Compounds) [%]. The weights of the individual detected compounds will be normalized to this total weight.
Calibration File (Peak Table) ④
This field and group of buttons work identically as the buttons in the Results tab.
Set…
Opens the Select Calibration dialog for linking a Calibration.
None
No calibration will be used.
View…
Displays the linked calibration.