Bio-Rad ChromLab™ Software - Manual (Page 236)

7 | Evaluating Results
234 | NGC Chromatography Systems and ChromLab Software
 Peak asymmetry — the asymmetry factor, defined as the distance from
the center line of the peak to the back slope divided by the distance from
the center line of the peak to the front slope. All measurements are made at
10% of the maximum peak height.
Note: The asymmetry factor of a peak is usually similar to the tailing factor
of the same peak, but the two values cannot be directly converted.
 Fractions — all fractions that reside between start and end. Multiple
fractions are displayed first to last.
 Peak type — the integration type for a peak.
 Automatic — the peak was determined automatically and has not been
manually adjusted.
 Manual — the peak has been manually adjusted or added.
 Path length (cm) — the path length of the UV detector’s flow cell. The
default length is 0.5 cm. The NGC system has three optional flow cells,
which are used to calculate the protein concentration: 0.2, 0.5, and 1.0 cm.
This field can be modified to display the value of the flow cell in use. When
the value in one row is changed the cell flow path length for all peaks in the
same run is updated accordingly.
 Extinction coefficient ((mg/ml)
-1
cm
-1
) — the extinction coefficient of the
protein, used to calculate the protein concentration. By default this field is
empty. You can enter a value up to three significant digits. Coefficient
values entered in the Peaks table automatically populate the extinction
coefficient values for relevant fractions in the Fractions table. Coefficient
values entered in the Fractions table are
not automatically populated to the
Peaks table.
 Concentration (mg/ml) — the calculated concentration of the protein for
the specified peak. This value is based on the following calculation:
(peak area/peak volume) / (extinction coefficient x path length x 1,000)