Test
Procedures
OQ/PQ Operating Instructions
M1393R0
Page 35 of 60
4.10
Gradient Accuracy
The gradient accuracy is tested by performing a step gradient. Water with a trace of
acetone is mixed with pure water. Detection of the acetone is performed at 254 nm.
Different gradient programs are used for the NAN and the CAP configurations (the NAN
program lasts 80 minutes while the CAP program is 50 minutes).
Typical examples of the step gradient profiles are presented in FIGURE 4-10 (NAN
configuration) and in FIGURE 4-11 (CAP configuration).
Legend
Step
a
0-5% B step
b
0-50% B step
c
0-100% B step
d
95-100% B step
e
step change time
c
d
e
a
b
FIGURE 4-10 Typical Step Gradient Profile – NAN Configuration
FIGURE 4-11 Typical Step Gradient Profile – CAP Configuration
The steps (items a- d, FIGURE 4-10) are quantified by measuring the UV absorbance
difference. The step delay (item e, FIGURE 4-10) represents response time of the gradient
formation and indicates that the volume of the tubings are correct.
