Hitachi ChromasterUltra Rs 6270 Instruction Manual page 113

(6) Data Check
Determine the Relative Standard Deviation (RSD) of peak
area by the following calculations.
Mean value
Standard deviation
Relative Standard Deviation
xi: Area value due to each injection,
n: Number of injections
Make sure the RSD value is 0.50 % or less (injection volume
is 1 µL). However, this value represents the reproducibility of
not the autosampler alone but the entire system. Therefore,
the value varies with each stability of the pump and detector,
accuracy of the data processing unit and its processing
parameters.
NOTE:
Close the front door when a sample vial is set. Avoid
rapid changes in ambient temperature, and not exposed
to drafts such as an air conditioner. These may influence
the analysis result which reproducibility with high
precision required.
NOTE:
Before starting an analysis, execute the needle washing
of autosampler to fill the needle, the injection port, and the
buffer tube with deaerated wash fluid1 (or wash fluid2,
when it is used). Otherwise, the deaeration state of the
wash fluid in the flow path will be changing gradually, so
reproducibility just after the analysis starting may be
unstable.
5 - 7
n

xi


i 1
x
n
n
 
2
( xi ) x


i 1
SD

n 1
SD
 
RSD 100
x
5.1.3
(%)