Thermo Fisher Scientific Ion Selective Electrodes Ammonium - Manual (Page 18)

Ammonium Electrode Instruction Manual
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3.
If electrode(s) fail this procedure, see the section on Measuring Hints .
4.
If the stability and the slope check out properly, but measurement problems persist, the
standards may be of poor quality, the sample may contain interference or complexing
agents, or the technique may be in error. See
Standard, Sample , and Technique sections
below.
5.
Before replacing a "faulty" electrode, review the instruction manual and be sure to:
clean and rinse the electrode thoroughly prepare the electrode properly use proper filling
solution, ISA, and standards measure correctly review
TROUBLESHOOTING HINTS.
Standard
The quality or results depends greatly upon the quality of the standards. ALWAYS prepare fresh
standard when problems arise. It could save hours of frustrating troubleshooting! Error may result
from contamination of prepared standards, accuracy of dilution, quality of distilled water, or a
mathematical error in calculating the standard concentrations.
Sample
If the electrode works properly in standard but not in sample, look for possible interference,
complexing agents, or substances which could affect response or physically damage the sensing
electrode or the reference electrode. See
Sample Requirements
and
Interference
. Try to determine
the composition of the samples prior to testing to eliminate a problem before it starts.
Technique
Check the method of analysis for compatibility with your sample. Direct measurement may not
always be the method of choice. Also be sure that the expected concentration of the ion of interest
is within the electrode's limits of detection.
If problems persist, review operational procedures and the instruction manual to be sure that proper
technique has been followed. Call Eutech Instruments Pte Ltd. at (65) 6778-6876 and ask for the
Customer Services Department to answer any questions.