YSI Professional Plus - Manual (Page 38)

66 67
sensor can be regenerated by washing with alcohol and/or gently polishing with
fine emery paper in a circular motion to remove any deposits or discoloration,
then thoroughly washing with deionized water to remove any debris. the
sensor may require soaking in the high standard chloride calibration solution to
recover its performance.
SENSoR MAINtENANCE - AMMoNIUM AND NItRAtE
Typical working life for ammonium and nitrate sensors is
approximately 3-6 months depending on usage, storage and
maintenance. Proper storage and maintenance generally
extends the sensor’s working life.
the ammonium and nitrate sensors are PVC membranes. As always, when
handling a sensor, care should be taken to avoid damaging the membrane. After
extensive use the membranes may become coated with a deposit or scoured
with fine scratches which may cause a slow or reduced response (low slope)
or unstable readings. Deposits may be removed with a fine jet of deionized
water or rinsing in alcohol followed by soaking in the high standard calibration
solution. Gently dab dry with a lint-free tissue before taking measurements.
sensor storaGe
SHoRt-tERM StoRAGE
the cable assembly is supplied with a sensor storage container, or sleeve, that
attaches to the cable. the container is used for short-term storage (less than 30
days). Be sure to keep a small amount of moisture (tap water) in the container
during storage. this is done to maintain a 100% saturated air environment which
is ideal for short-term sensor storage. the sensors should not be submersed in
water. the intent is to create a humid air storage environment.
LoNG-tERM StoRAGE
Long-term Storage - temperature
No special storage is required. the temperature sensor can be stored dry or
wet as long as solutions in contact with the thermistor are not corrosive (for
example, chlorine bleach).
Long-term Storage Temperature: -5 to 70°C (23 to 158°F)
Long-term Storage - Conductivity
No special storage is required. Sensors can be stored dry or wet as long as
solutions in contact with conductivity electrodes are not corrosive (for example,
chlorine bleach). However, it is recommended that the sensor be cleaned with
the provided brush prior to and after long term storage.
Long-term Storage Temperature: -5 to 70°C (23 to 158°F)
Long-term Storage - Dissolved oxygen
Dissolved oxygen sensors (Polarographic and Galvanic) should be stored in a
dry state for long term storage First, remove the membrane cap and thoroughly
rinse the sensor with clean water. Next, either blow it dry with compressed air
or allow to air dry completely. Install a clean, dry new membrane cap over the
sensor to keep it dry and to protect the electrodes.
After storing the sensor for a long period of time, it is necessary to “condition” the
sensor by putting a new membrane with electrolyte solution on the sensor and
then turning the instrument on to allow the sensor sufficient time to stabilize.
Long-term Storage Temperature: -5 to 70°C (23 to 158°F)
Long-term Storage - pH
the key to pH sensor storage, short or long-term, is to make certain that the
sensor does not dry out. Sensors which have been allowed to dry out due to
improper storage procedures may be irreparably damaged by the dehydration
and will require replacement. You can try to rehydrate the sensor by soaking it
(preferably overnight) in a potassium chloride solution or a pH 4 buffer before
attempting to calibrate.
to store the sensor, remove it from the cable and seal the vacant port with a port
plug. Fill the original shipping/storage vessel (plastic boot or bottle) with buffer
4 solution and then submerge the sensor into the solution. the sensor should
remain submerged in the solution during the storage period; therefore, make
certain that the vessel is sealed to prevent evaporation and periodically check the
vessel to ensure the sensor does not dry out.
Long-term Storage Temperature: 0 to 30°C (32 to 86°F)
It is important not to store the pH sensor in distilled or deionized
water as the glass sensor may be damaged by exposure to this
medium.
i
i