Example chromatogram showing signal as a function of retention time In chromatography , resolution is a measure of the separation of two peaks of different retention time t in a chromatogram .[ 1] [ 2] [ 3] [ 4]
Expression
Chromatographic peak resolution is given by
R
s
=
2
t
R
2
−
t
R
1
w
b
1
+
w
b
2
{\displaystyle R_{s}=2{\cfrac {t_{R2}-t_{R1}}{w_{b1}+w_{b2}}}}
where tR is the retention time and wb is the peak width at baseline. The bigger the time-difference and/or the smaller the bandwidths, the better the resolution of the compounds. Here compound 1 elutes before compound 2.
If the peaks have the same width
R
s
=
t
R
2
−
t
R
1
w
b
{\displaystyle R_{s}={\cfrac {t_{R2}-t_{R1}}{w_{b}}}}
Plate number
Two resolved peaks in a chromatogram The theoretical plate height is given by
H
=
L
N
{\displaystyle H={\frac {L}{N}}}
where L is the column length and N the number of theoretical plates.[ 5]
N
=
16
⋅
(
t
R
W
b
)
2
{\displaystyle N=16\cdot \left({\frac {t_{R}}{W_{b}}}\right)^{2}\,}
See also
References
^ IUPAC , Compendium of Chemical Terminology Peak Resolution Rs in chromatography ". doi :10.1351/goldbook.P04465 ^ IUPAC , Compendium of Chemical Terminology Peak Resolution in gas chromatography ". doi :10.1351/goldbook.R05317 ^ Maryutina, Tatiana A.; Savonina, Elena Yu.; Fedotov, Petr S.; Smith, Roger M.; Siren, Heli; Hibbert, D. Brynn (2018). "Terminology of separation methods (IUPAC Recommendations 2017)" . Pure and Applied Chemistry . 90 (1): 181– 231. doi :10.1515/pac-2017-0111 ISSN 0033-4545 . ^ Ettre, L. S. (1993). "Nomenclature for chromatography (IUPAC Recommendations 1993)" . Pure and Applied Chemistry . 65 (4): 819– 872. doi :10.1351/pac199365040819 ISSN 1365-3075 . ^ IUPAC , Compendium of Chemical Terminology plate number, N ". doi :10.1351/goldbook.P04694
External links
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