Hamilton SUS pH electrodes Quality Declaration All sensors delivered with Quality Declaration The Quality Declaration contains all information needed for startup Hamilton SUS pH electrodes Quality Declaration ID: 783978
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Slide1
Calibration of SUSpH electrodes
Slide2Hamilton SUS pH electrodes
Quality Declaration :
All sensors delivered with Quality Declaration
The Quality Declaration contains all information needed for start-up
Slide3Hamilton SUS pH electrodes
Quality Declaration
: Zero point
Most equipment (controllers or transmitters) need zero point value and slope
The zero point value is the mV value at pH 7, directly provided in the declaration
Slide4Hamilton SUS pH electrodes
Quality Declaration
: Slope
The slope is calculated based on zero point value and pH 4 reading according to following formula (all mV values at 25°C) :
Slope
= [
E(pH4.01)-E(pH7.00)]
/ [(
pH=4.01)
–
(pH=7.00)]
In
previous
example
:
Slope
= (181 – 4)/-2.99 = -59.2mV/pH
Slide5Hamilton SUS pH electrodes
Quality Declaration
: Zero point as pH value for
0
mV
Some equipment may need the slope and instead the zero point, they require the pH value to get 0mV. This one can be calculated as follows :
pH
(E=0mV) = [pH7*E(pH4) – pH4*E(pH7)]/(EpH4-EpH7)] =
In
previous
example
:
pH
(E=0mV)
=
[
7.00*181
–
4.01*4]
/
[181-4] =
(
1267– 16.04) / (177) = 7.067
Slide6Hamilton SUS pH electrodes
During process calibration :
Some
processes may require pH adjustments of the electrode during process and without removing the electrode from the vessel. This procedure is called “product calibration”. The user takes a sample of medium (through sterile sample valve) and makes a reference pH measurement (in lab). In case the reference value differs from process value more than a user pre-defined tolerance, an adjustment is required. It consists of an offset adjustment, the slope remains unchanged. Hamilton SUS electrodes can be handled is this way, the procedure however must be supported by the controller / transmitter.
Slide7Thank you for your attention!
Hamilton
Bonaduz
AG
, Switzerland
Hamilton Company
, Reno / USA