Xylem ISE Electrodes Pb 60 - Handbuch (Seite 19)

19
Response times
The response time depends on the concentration range.
It is:
• several seconds with high concentrations,
• several minutes near the detection limit.
The measured value is stable if the value does not change
by more than 0.1 mV within 30 seconds.
Interferences
•
Cupric, mercury and silver ions poison the membrane.
•
Iron and cadmium ions poison the membrane if their
concentrations are higher than that of the lead
concentration.
Aging
Please note that every electrode undergoes a natural aging
process. The response time increases and the slope
decreases with the age of the electrode. The following
factors shorten the lifetime considerably:
• Incorrect storing
• Special measuring conditions (e.g. organic solutions,
frequent measuring with high concentrations of
interfering ions)
• High temperatures
• High changes in temperature
The warranty does not cover damage caused by measuring
conditions and mechanical damage.