9. Column Efficiency
The number of theoretical plates of a column (N), the asymmetry factor (As) and their
chromatographic conditions are shown in the Inspection Data.
9-1 Method of Calculating the Number of Theoretical Plates
Fig. 4 Method of Calculating the Number of Theoretical Plates
The number of theoretical plates of a column (N) is calculated by the half peak width
method shown in Fig.4 and the following equation.
N＝5.54(Ve／W
1／2
)
2
Ve
: Elution volume
W
1／2
: Half width value of peak
h
: Peak height
9-2 Method of Calculating the Asymmetry Factor
Fig. 5 Method of Calculating the Asymmetry Factor
The asymmetry factor of column (As) is calculated by the 1／10 h method.
As ＝ b／a
9-3 Dead Volume
If the dead volume of the equipment or the injection volume of a sample solution
becomes too large, the number of theoretical plates may decrease.
− ６ −
Ve
h
W
Injection
1/2
1/2h
Ve
h
a
b
Injection
1/10h
