Performance Table

A table containing peak parameters characterizing the quality of the chromatographic system. Invoking the command opens the Performance tab.

Chromatogram - Performance

The left-hand part contains the table, while on the right part the calculation type is selected.

Elements of the Performance Table

Element	Description
Upper Caption	- Shows column names. To display the values of the table in an ascending order, double-click the upper caption; double-click again to change the order to descending. Move the column to some other position by left clicking the mouse twice slowly and dragging the cursor above the desired column. To broaden or narrow a column, click, hold down and then drag the right border. Restore the default column width by double-clicking the right border.
Left caption	- Displays the peak number.
Reten. Time	- Retention time in minutes.
W05 [min]	- Peak half-width (peak width at half-height) in minutes. This column displays only if the Performance table is created using Width at 50%.
Compound Name	- Names of identified compounds.

 

The following columns vary depending on the type of calculation used:

Statistical Moments

List of columns in the Performance Table - Statistical Moments

Column	Equation
Centroid [min]	- Peak centroid: where:
Variance [min2]	- Peak variance:
Skew [-]	- A measure of peak skewness: where:
Excess [-]	- A measure of Kurtosis: where:
Efficiency	- Column efficiency measured by the plate number:
Eff./l	- Relative efficiency:
Symmetry/Tailing [-]	- Symmetry/Tailing:

From Width at 50%:

List of columns in the Performance Table - Width at 50%

Column	Equation
Asymmetry[-]	- Peak asymmetry:
Capacity[-]	- The k' factor
Efficiency	- Column efficiency measured by the plate number:
Eff./l	- Relative column efficiency in plate numbers per column length:
Resolution[-]	- Represents resolution with regard to the preceding peak:

Description of used symbols

Symbol	Description
RTi	- is the retention time of the component.
Wh/2i	- is the peak width at half height.
ai	- is the left half-width at 10 % height.
bi	- is the right half-width at 10 % height.
T0	- is the unretained (dead) time of the column.
Column Length	- in mm.
A05i	- is the left half-width at 5 % height.
B05i	- is the right half-width at 5 % height.

Parameters influencing the calculation are stated in the right-hand part of the Performance tab:

Unretained Peak Time

The parameter defines the column dead time in minutes. The value is used to determine the capacity factor.

Column Length

The length of the column in millimeters. The value is used to calculate the theoretical column plate height.

Column Calculations

The method used to calculate some parameters in the table is specified here.

Statistical Moments - Calculations are based on statistical moments.

From Width at 50% - The peak width at 50% of the peak height and the corresponding half widths are used in the calculations.