Agilent Technologies 8453 - Number of Theoretical Plates Per Meter N [1;M]; Relative Retention (USP, ASTM), Selectivity Alpha

248 Understanding Your Agilent ChemStation
11 Evaluating System Suitability
Performance Test Definitions
5 Sigma method:
where:
W
4.4
= peak width at 4.4% of peak height [min]
Variance method:
where:
Mx = x
th
statistical moment (see also “Statistical Moments” on page 244)
Number of Theoretical Plates per Meter N [1/m]
where:
n = number of theoretical plates
l = length of column [cm]
Relative Retention (USP, ASTM), Selectivity Alpha
(Pertaining to peaks a and b, T
R
of peak a < T
R
of peak b)
where:
k'
(x)
= capacity factor for peak x