NAVI F-52, Instruction Manual

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Chapter 5 Ion Measurement (F-53,55)
5.3 Measurement Using Standard Addition Method
F-52, 53, 54, 55 67
5.3
Measurement Using Standard Addition Method
The standard addition method is classified into the known addition method, the known sub-
traction method, and modifications called the sample addition method and the sample subtrac-
tion method. These methods are effective when the composition varies depending on the
samples and it is difficult to control conditions such as pH and ionic strength.
The F-series pH meter supports the known addition method and the sample addition method.
For the known addition method, refer to JIS K0122.
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Known Addition Method and Sample Addition Method
Known addition method
For the known addition method, a small amount of standard solution for the ion species to
measure is added to the sample solution to increase the amount of the target component (con-
centration of the ion species under measurement) by a certain amount. The sample concentra-
tion is obtained by the change in electric potential that occurs at that time.
Sample addition method
For the sample addition method, a small amount of sample is added to the standard solution
for the ion species to measure to increase the amount of the target component (concentration
of the ion species under measurement). The sample concentration is obtained by the change in
electric potential that occurs at that time.
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Standard Addition 1 and Standard Addition 2
Standard addition 1
In the STANDARD ADDITION 1 mode, the standard solution for the ion species to measure
is added once to the sample solution.
Standard addition 2
In the STANDARD ADDITION 2 mode, the standard solution for the ion species to measure
is added twice to the sample solution. This mode is used to obtain the target ion concentration
in the sample solution and the electric potential slope of the electrode used.
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Sample Addition 1 and Standard Addition 2
Sample addition 1
In the SAMPLE ADDITION 1 mode, the sample is added once to the standard solution for
the ion species to measure.
Sample addition 2
In the SAMPLE ADDITION 2 mode, the sample is added twice to the standard solution for
the ion species to measure. This mode is used to obtain the target ion concentration in the
sample solution and the electric potential slope of the electrode used.