RADIOMETER ABL800 FLEX Reference Manual

ABL800 FLEX Reference Manual 1. Potentiometric measuring principles
General information, Continued
Calibration line
(continued)
To describe the actual condition of the electrode, its calibration line is compared to
the calibration line of the theoretical electrode.
Theoretical calibration line
pH
Measured
potential
(mV)
−
112.4
−
75.5
6.8
7.4
The theoretical electrode is
defined to measure the
following:
−112.4 mV at pH 7.400,
−75.5 mV at pH 6.800.
The position and slope of the calibration line compared to the theoretical
calibration line are described by the status and sensitivity.
Sensitivity
The electrode sensitivity illustrates the slope of the calibration line compared to the
slope of the theoretical electrode.
The sensitivity of the theoretical electrode is 100 % or 1.00.
Theoretical calibration line
Slope= −61.5 mV/pH
Sensitivity = 100 %
pH
Measured
potential
(mV)
−
112.4
−
75.5
6.8
7.4
2-point calibration line
Slope =
−
58.4 mV/pH
Sensitivity = 95 %
If an electrode
has a sensitivity
of 95 % or 0.95,
its sensitivity is
5 % lower than
the theoretical
electrode.
The sensitivity of an electrode is calculated as:
(%)
)802.6398.7(5.61
398.7802.6
−×
−
=
atPotentialatPotential
ySensitivit
where 61.5 = sensitivity of theoretical electrode.
Each electrode has its own sensitivity limits.
Continued on next page
1-5

RADIOMETER ABL800 FLEX Specifications

General

Brand	RADIOMETER
Model	ABL800 FLEX
Category	Measuring Instruments
Language	English