RADIOMETER ABL90 FLEX - Page 13

ABL90 FLEX reference manual Contents
Sample measurements............................................................... 5-8
Corrections............................................................................... 5-8
Quality Management.......................................................................... 5-9
Introduction.............................................................................. 5-9
System/ analysis checks............................................................. 5-9
Calibration...............................................................................5-12
Measurement...........................................................................5-12
Reference electrode..........................................................................5-13
Background information about the reference electrode ..........................5-14
Purpose...................................................................................5-14
Fixed potential .........................................................................5-14
Use.........................................................................................5-14
Construction of the reference electrode ...............................................5-15
Diagram..................................................................................5-15
Parts and functions ...................................................................5-15
pH and electrolyte sensors ................................................................5-16
Construction of the pH and electrolyte sensors .....................................5-17
Diagram..................................................................................5-17
Parts and description.................................................................5-17
Measuring principle of the pH and electrolyte sensors............................5-18
Potentiometric measuring principle..............................................5-18
Electrode chain.........................................................................5-18
Parts and description.................................................................5-18
Electrode chain potential............................................................5-18
Unknown potential....................................................................5-19
Ion-sensitive membrane............................................................5-19
Nernst equation........................................................................5-19
Activity and concentration..........................................................5-19
Calibration of the pH and electrolyte sensors........................................5-20
Introduction.............................................................................5-20
2-point calibration ....................................................................5-20
Calibration levels......................................................................5-20
Calibration...............................................................................5-20
Measurement – pH and electrolytes ....................................................5-21
Measurement...........................................................................5-21
Checks....................................................................................5-21
pCO
2
sensor....................................................................................5-22
Construction of the pCO
2
sensor.........................................................5-23
Diagram..................................................................................5-23
Parts and description.................................................................5-23
Measuring principle of the pCO
2
sensor ...............................................5-24
Electrode chain.........................................................................5-24
Parts and description.................................................................5-24
Electrode chain potential............................................................5-24
Measuring process ....................................................................5-25
Calibration of the pCO
2
sensor ...........................................................5-26
Introduction.............................................................................5-26
Calibration levels......................................................................5-26
Sensitivity ...............................................................................5-26
Measurement – pCO
2
........................................................................5-27
Measurement...........................................................................5-27
Checks....................................................................................5-27
pO
2
sensor......................................................................................5-28
Measuring principle of the pO
2
sensor .................................................5-29
Optical system for pO
2
...............................................................5-29