YSI Professional Plus User Manual

Page 37

SENSoR MAINtENANCE - CoNDUCtIVItY

the openings that allow sample access to the conductivity electrodes should be

cleaned regularly. the small cleaning brush included in the Maintenance Kit is

ideal for this purpose. Dip the brush in clean water and insert it into each hole 10

to 12 times. In the event that deposits have formed on the electrodes, it may be

necessary to use a mild detergent (laboratory grade soap or bathroom foaming

tile cleaner) with the brush. Rinse thoroughly with clean water, then check the

response and accuracy of the conductivity cell with a calibration standard.

If this procedure is unsuccessful, as indicated by improper

electrode performance, contact YSI Technical Support or the

Authorized dealer where you purchased the instrument.

SENSoR MAINtENANCE - tEMPERAtURE

You must keep the temperature portion of the sensor free of build up. other

than that, the sensor requires no maintenance. the conductivity cleaning brush

can be used to scrub the temperature sensor if needed. Alternatively, you can

use a toothbrush to clean the sensor.

SENSoR MAINtENANCE -

pH, oRP AND CoMBINAtIoN pH/oRP

Typical working life for pH and ORP sensors is approximately 12-24

months depending on usage, storage, and maintenance. Proper

storage and maintenance generally extends the sensor’s working life.

Cleaning is required whenever deposits or contaminants appear on the glass

and/or platinum surfaces or when the sensor’s response slows. the cleaning can

be chemical and/or mechanical.

Removing the sensor from the cable may make cleaning easier. Initially, use

clean water and a soft clean cloth, lens cleaning tissue, or cotton swab to remove

all foreign material from the glass bulb and/or platinum button. then use a

moistened cotton swab to carefully remove any material that may be blocking

the reference electrode junction of the sensor.

CAUTION: When using a cotton swab, be careful NOT to

wedge the swab between the guard and the glass sensor. If

necessary, remove cotton from the swab tip, so that the cotton

can reach all parts of the sensor tip without stress. You can

also use a pipe cleaner for this operation if more convenient.

If good pH and/or oRP response is not restored, perform the following additional

procedure:

Soak the sensor for 10-15 minutes in clean water containing a few

drops of commercial dishwashing liquid.

GENtLY clean the glass bulb and platinum button by rubbing with

a cotton swab soaked in the cleaning solution.

Rinse the sensor in clean water, wipe with a cotton swab saturated

with clean water, and then rerinse with clean water.

If good pH and/or oRP response is still not restored, perform the following

additional procedure:

Soak the sensor for 30-60 minutes in one molar (1 M) hydrochloric

acid (HCl). this reagent can be purchased from most lab supply

distributors. Be sure to follow the safety instructions included with

the acid.

Rinse the sensor in clean water, wipe with a cotton swab saturated

with clean water (not DI water), and then rerinse with clean water.

to be certain that all traces of the acid are removed from the sensor

crevices, soak the sensor in clean water for about an hour with

occasional stirring.

If biological contamination of the reference junction is suspected or if good

response is not restored by the above procedures, perform the following

additional cleaning step:

Soak the sensor for approximately 1 hour in a 1:1 dilution of

commercially-available chlorine bleach.

Rinse the sensor with clean water and then soak for at least 1 hour

in clean water with occasional stirring to remove residual bleach

from the junction. (If possible, soak the sensor for a period of time

longer than 1 hour in order to be certain that all traces of chlorine

bleach are removed.) then rerinse the sensor with clean water and

retest.
Dry the port and sensor connector with compressed air and apply a

very thin coat of o-ring lubricant to all o-rings before reinstallation.

SENSoR MAINtENANCE - CHLoRIDE

Typical working life for chloride sensors is approximately 3-6

months depending on usage, storage, and maintenance. Proper

storage and maintenance generally extends the sensor’s working life.

the chloride sensor is considered a pellet membrane ISE. As always, when

handling sensors, care should be taken to avoid damaging the membrane. this