112
7 Validation of the Measurement Procedure
Table 7.12 Scheme of the experiments enabling the evaluation of robustness of the analytical
procedure
Value of
parameters
Set of parameters
1
2
3
4
5
6
7
8
A/a
A
A
A
A
a
a
a
a
B/b
B
B
b
b
B
B
b
b
C/c
C
c
C
c
C
c
C
c
D/d
D
D
d
d
d
d
D
D
E/e
E
e
E
e
e
E
e
E
F/f
F
f
f
F
F
F
F
F
G/g
G
g
g
G
g
G
G
g
Result
s
t
u
v
w
x
y
z
identified. Let’s assume that the nominal value of the factor is denoted by an uppercase
character (e.g., A, B, …) and the robust value is denoted by a lowercase character
(e.g., a, b, c, …). The typical manner for how to conduct the evaluation of robustness
for eight identified factors is given in a Table 7.12.
The measurements should be conducted under eight sets of conditions with randomly but systematically selected nominal and random values of the critical factors.
If set 1 was used, the result s was obtained, if set 2 was used, the result t was
obtained, and so on. To evaluate the effect of a variable factor, one must select four
results where the given factor value was nominal (uppercase) and the four results
were the given factor was robust (lowercase) and compare the mean values for both
sets of results. For example, to determine the impact of pH, the following values
should be compared: the mean values for the results obtained under nominal conditions (s + u + w + y)/4 versus the mean value for the results obtained under robust
conditions (t + v + x + z)/4. Such a calculation should be performed for all selected
factors, then the values of the differences must be sorted out according to ascending or descending values, so as to note those with the most (significant) impact on
the result. If there are no significant differences, calculate the mean and standard
deviation of the eight results from s to z, which allows the robustness of the applied
measurement procedure to be determined.
7.22 Summary
The validation of the measurement procedure is a tool used in a testing or calibration laboratory that allows the selected parameters of the given procedure to be
determined, as well as confirming that they are suitable for its intended use.
7 Validation of the Measurement Procedure
Table 7.12 Scheme of the experiments enabling the evaluation of robustness of the analytical
procedure
Value of
parameters
Set of parameters
1
2
3
4
5
6
7
8
A/a
A
A
A
A
a
a
a
a
B/b
B
B
b
b
B
B
b
b
C/c
C
c
C
c
C
c
C
c
D/d
D
D
d
d
d
d
D
D
E/e
E
e
E
e
e
E
e
E
F/f
F
f
f
F
F
F
F
F
G/g
G
g
g
G
g
G
G
g
Result
s
t
u
v
w
x
y
z
identified. Let’s assume that the nominal value of the factor is denoted by an uppercase
character (e.g., A, B, …) and the robust value is denoted by a lowercase character
(e.g., a, b, c, …). The typical manner for how to conduct the evaluation of robustness
for eight identified factors is given in a Table 7.12.
The measurements should be conducted under eight sets of conditions with randomly but systematically selected nominal and random values of the critical factors.
If set 1 was used, the result s was obtained, if set 2 was used, the result t was
obtained, and so on. To evaluate the effect of a variable factor, one must select four
results where the given factor value was nominal (uppercase) and the four results
were the given factor was robust (lowercase) and compare the mean values for both
sets of results. For example, to determine the impact of pH, the following values
should be compared: the mean values for the results obtained under nominal conditions (s + u + w + y)/4 versus the mean value for the results obtained under robust
conditions (t + v + x + z)/4. Such a calculation should be performed for all selected
factors, then the values of the differences must be sorted out according to ascending or descending values, so as to note those with the most (significant) impact on
the result. If there are no significant differences, calculate the mean and standard
deviation of the eight results from s to z, which allows the robustness of the applied
measurement procedure to be determined.
7.22 Summary
The validation of the measurement procedure is a tool used in a testing or calibration laboratory that allows the selected parameters of the given procedure to be
determined, as well as confirming that they are suitable for its intended use.