Instruction Manual

7
Signet 2724-2726 and 2734-2736 Series pH and ORP Electrodes
Problem Suggested Solution
Hard Coatings
Use a dilute acid solution (HCl solution of 5% or less). If the electrode has been used in
applications with a pH value higher than 7 pH, soak the electrode for 2 to 5 minutes.
Use a dilute alkaline solution (NaOH solution at 5% or less) if the electrode has been used in
applications with pH values less than 7 pH, soak the electrode for 2 to 5 minutes.
Alternating immersion in acidic and alkaline solutions may be necessary for thorough cleaning.
Soft Coatings
Spray or vigorously stir the electrode with a mild detergent, such as dishwashing liquid.
Chlorine bleach can also be used.
Oily or Organic Coatings
Spray or vigorously stir the electrode with a mild detergent or an appropriate solvent that
will not attack the materials of construction. (isopropyl alcohol or similar)
ORP Platinum Coating Gently wipe the electrode surfaces with a paper towel.
After Cleaning
Always rinse the electrode with water after cleaning.
Soak the electrode in a pH 4 buffer (with KCl if available) for at least 10 minutes after cleaning.
pH/ORP electrodes are similar to batteries; they age with time and usage.
The following information will help maximize electrode life.
General Tips:
• To ensure uninterrupted operation of critical pH systems, replacement electrodes should be available.
• Store boxed electrodes fl at or upright (electrode tip down) to maximize hydration of the glass surface.
• Keep the glass surface wet at all times.
• Soak the sensor tip in pH 4.0 buffer during system maintenance intervals.
• If the sensor dehydrates, soak the sensor tip in pH 4 buffer for 24 to 48 hours,
then visually inspect the electrode for surface cracks, swelling, or discoloration.
• It may not be possible to restore severely dehydrated electrodes to normal operation.
• High temperatures, strong acids or caustics will increase electrochemical reactions and speed electrode aging.
• Coatings (e.g. grease) on the glass or junction surfaces cause extended response time and inaccurate measurement.
• Never store the electrode tip in deionized (DI) water. Use pH 4 buffer solution to keep the glass wet when out of the process.
• Never store the electrode at temperatures below 0 °C (32 °F) or allow it to dehydrate.
• Never scrape or sand the glass electrode surface.
• Treat glass electrode surfaces with care to prevent accidental breakage.
• The electrode date code indicates the
manufacturing date of the electrode.
• Electrodes should be put into service as
soon as possible and should not remain in
the box for more than two years.
• Over time, the storage solution (found in
the "boot" covering the electrode tip) will
evaporate or leak, allowing the delicate
sensing tip and reference junction to dry.
• To rehydrate a dry electrode, soak it in
pH 4 buffer for 24 to 48 hours.
• Electrodes more than 2 years old may still be
functional, but will take longer to rehydrate.
• Restoration may not be effective for severely
dehydrated electrodes.
Cleaning
Electrode Care and Application
Electrode Date Code
Maintenance and Cleaning
Numeral = Year
5 = 2010
6 = 2011
7 = 2012
8 = 2013
9 = 2014
0 = 2015
1 = 2016
2 = 2017
3 = 2018
4 = 2019
5 = 2020
6 = 2021
Letter = Month
N = January
M = February
L = March
K = April
J = May
H = June
G = July
F = August
E = September
D = October
C = November
B = December
K4
K4
K4
K4
Example: K8 = manufactured in April 2013