system suitability - mohsin al-saleh · 2017. 3. 11. · zsystem suitability the checking of a...
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System Suitability
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©2005 Waters Corporation
System Suitability
System SuitabilityThe checking of a system, before or during analysis of unknowns, to insure system performance.Plate Count, Tailing, Resolution, Capacity FactorDetermination of reproducibility (%RSD)
System Suitability "Sample"A mixture of main components and expected by-products utilized to determine system suitability
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©2005 Waters Corporation
System Suitability
Reproducibility
Separation Review
System Troubleshooting
SystemSuitability
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©2005 Waters Corporation
ReproducibilityPrecision
The measure of the degree of agreement among test results when the method is applied repeatedly to multiple samplings of a homogeneous sampleExpressed as %RSD for a statistically significant number of samples
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©2005 Waters Corporation
Definition of SpecificitySpecificity (Selectivity)
The ability to measure accurately and specifically the analyte in the presence of components that may be expected to be present in the matrixThe degree of interference
Active IngredientsExcipientsImpuritiesDegradation ProductsPlacebo Ingredients
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©2005 Waters Corporation
Specificity (Selectivity)
SeparationResolution
Determination of separation between peaks
Plate CountDetermination of a systems efficiency
Tailing FactorCalculation referencing peak shape
PDAPurity AnglePurity Plots
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©2005 Waters Corporation
Resolution RR = 1 2% Overlap 4σR = 1.5 baseline separation 6σ
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©2005 Waters Corporation
Resolution R
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©2005 Waters Corporation
1 .0 1 .2 5
9 9 .4
9 8
9 5
0 .8
8 88 3
R s = 0 .40 .5 0 .6
0 .7
9 2
The value of 1.5 or more, indicates that peaks are separated through base line.
Resolution R
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©2005 Waters Corporation
Capacity factor k´
mobilephasestat
AmountAmount
VVKk
m
s.´ ==
K = Cs
Cmsubstitute
=Ms Vm
Mm Vs
k´=vr-v0v0 =
tr-t0t0
Capacity Factor describes the migration rate of an analyte through a column
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©2005 Waters Corporation
N = Theoretical PlatesA Measure of Efficiency
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©2005 Waters Corporation
EfficiencyPeak broadening during separation
minutes0 126
W = 0,55 min
10,2 min
N = 16 (tr/w)2 = 16 *(10,2 / 0,55)2= 5500
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©2005 Waters Corporation
Calculation of Column Efficiency5σ Method
7018.=RV
plates 8240
1.0318.7025N
2
5
=
⎥⎦⎤
⎢⎣⎡=
1.03W =
height4.4%
height4.4%
plates 3334
N5
=
⎥⎦⎤
⎢⎣⎡=σ
2
441631625
..
6316.=RV
1.44W =
Good Column Bad Column
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©2005 Waters Corporation
• Factors that will influence the efficiency, N :– Flow rate (linear velocity)– Column length– Particle size– Particle size distribution– Porosity– Injection volume– Solvent viscosity– Column temperature– Particle shape (spherical versus irregular)– Retention– Extra column band spreading (in tubing and
instruments)
Optimizing efficiency, N
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©2005 Waters Corporation
Asymmetry Factor
ABAs =
4.4%
A B
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©2005 Waters Corporation
FDA Guidelines for System Suitability
Parameters Guidelines
Repeatability of peak response
1.0% for 5 replicates
Resolution Minimum 2.0
Tailing factor Less then or equal to 1.0
Column efficiency Greater then 2000 (plate count)
Capacity factor Greater then 2
Slide Number 1Slide Number 2Slide Number 3Slide Number 4Definition of SpecificitySpecificity (Selectivity)Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16
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