WPI ISO-HPO-2 User manual

ISO-HPO-2
Hydrogen peroxide sensor for use with
WPI Free Radical Analyzers
World Precision Instruments
INSTRUCTION MANUAL
Serial No._____________________
040808
www.wpiinc.com
ISO-HPO-2
World Precision Instruments, Inc.
USA
International Trade Center, 175 Sarasota Center Blvd., Sarasota FL 34240-9258
Tel: [phone] • Fax: [phone] • E-mail: [e-mail]
UK
Astonbury Farm Business Centre • Aston, Stevenage, Hertfordshire SG2 7EG
Tel: [phone] • Fax: [phone] • E-mail: [email protected]
Germany
Liegnitzer Str. 15, D-10999 Berlin
Tel: [phone] • Fax: [phone] • E-mail: [email protected]
Internet
www.wpiinc.com • www.wpi-medical.com
www.nitricoxide.net •www.pipetter.com
Warranty
WPI (World Precision Instruments, Inc.) warrants to the original purchaser that this equipment,
including its components and parts, shall be free from defects in material and workmanship for a
period of 30 days from the date of receipt. WPI’s obligation under this warranty shall be limited
to repair or replacement, at WPI’s option, of the equipment or defective components or parts upon
receipt thereof f.o.b. WPI, Sarasota, Florida U.S.A. Return of a repaired instrument shall be f.o.b.
Sarasota.
The above warranty is contingent upon normal usage and does not cover products which have
been modied without WPI’s approval or which have been subjected to unusual physical or
electrical stress or on which the original identication marks have been removed or altered. The
above warranty will not apply if adjustment, repair or parts replacement is required because of
accident, neglect, misuse, failure of electric power, air conditioning, humidity control, or causes
other than normal and ordinary usage.
To the extent that any of its equipment is furnished by a manufacturer other than WPI, the
foregoing warranty shall be applicable only to the extent of the warranty furnished by such other
manufacturer. This warranty will not apply to appearance terms, such as knobs, handles, dials or
the like.
WPI makes no warranty of any kind, express or implied or statutory, including without limitation
any warranties of merchantability and/or tness for a particular purpose. WPI shall not be liable
for any damages, whether direct, indirect, special or consequential arising from a failure of this
product to operate in the manner desired by the user. WPI shall not be liable for any damage to
data or property that may be caused directly or indirectly by use of this product.
Claims and Returns
• Inspect all shipments upon receipt. Missing cartons or obvious damage to cartons should be
noted on the delivery receipt before signing. Concealed loss or damage should be reported at
once to the carrier and an inspection requested. All claims for shortage or damage must be made
within 10 days after receipt of shipment. Claims for lost shipments must be made within 30 days
of invoice or other notication of shipment.
Please save damaged or pilfered cartons until claim settles. In some instances, photographic
documentation may be required. Some items are time sensitive; WPI assumes no extended
warranty or any liability for use beyond the date specied on the container.
• WPI cannot be held responsible for items damaged in shipment en route to us. Please enclose
merchandise in its original shipping container to avoid damage from handling. We recommend
that you insure merchandise when shipping. The customer is responsible for paying shipping
expenses including adequate insurance on all items returned.
• Do not return any goods to WPI without obtaining prior approval and instructions (RMA#) from
our returns department. Goods returned unauthorized or by collect freight may be refused. The
RMA# must be clearly displayed on the outside of the box, or the package will not be accepted.
Please contact the RMA department for a request form.
• Goods returned for repair must be reasonably clean and free of hazardous materials.
• A handling fee is charged for goods returned for exchange or credit. This fee may add up to 25%
of the sale price depending on the condition of the item. Goods ordered in error are also subject to
the handling fee.
• Equipment which was built as a special order cannot be returned.
• Always refer to the RMA# when contacting WPI to obtain a status of your returned item.
• For any other issues regarding a claim or return, please contact the RMA department
Warning: This equipment is not designed or intended for use on humans.

ISO-HPO-2
When the ISO-HPO-2 sensor is not being used it should be left connected
to a WPI free radical system with the tip immersed in PBS (phosphate
buffered saline). The basic structure of the ISO-HPO-2 sensor is quite simple
(see gure). It consists of an internal H2O2-sensing working/reference
electrode combination. This electrode ts inside a disposable protective
stainless steel sleeve (WPI #600012) which must contain fresh electrolyte
(WPI #100042) and is separated from the external environment by a
polymeric membrane covering the end of the stainless sleeve. The other end
of the sleeve is anged. The locking cap is used to attach the sleeve to the
probe handle.
When the sensor is fully assembled (i.e., with locking cap and sleeve in
place) the internal electrode should be seen to press gently against the
polymeric membrane, which will then be slightly stretched. This ensures
that the electrolyte diffusion layer will be as thin as possible, which is
necessary to minimize sensor response time. Once a membrane is stretched,
it is permanently deformed and cannot usually be reused if the sleeve
is removed from the electrode. Four additional membrane sleeves (WPI
#600012) accompany the ISO-HPO-2 in the start-up kit (WPI #600011),
together with a MicroFil™ electrolyte lling needle (WPI #MF28G67-5) and
1 mL syringe. With proper care and by following the instructions below a
membrane sleeve should last more than one month.
Cleaning the Membrane
The membrane sleeve itself requires very little maintenance. The primary
concern is to avoid damage to the membrane and to keep it as clean as
possible. After each use, clean the membrane by immersing the tip in
distilled water for 20-30 minutes to dissolve salts and remove particles
which may have accumulated on the membrane. If the probe was used in a
protein-rich solution, the membrane tip should rst be soaked in a protease
solution for several minutes to remove protein build-up, and then in distilled
water. Enzymatic detergent (e.g., Enzol, WPI #7363) can also be used. The
membrane sleeves can also be sterilized chemically using an appropriate
disinfectant (e.g., Cidex, WPI #7364). Accumulated organic matter can
be removed by briey immersing the tip in an acid or base solution (at
times both may be necessary) for 10 seconds. A good indication of a dirty
membrane sleeve is a sluggish response or an unusually low sensitivity. If
these problems are not rectied by the above cleaning procedures then the
membrane sleeve should be replaced. The probe cannot be used in organic
solvents.
Replacing a Membrane Sleeve
All membrane sleeves will eventually have to be replaced by the user. The
procedure for doing so is simple and straightforward.
1. Unscrew the locking cap from the handle.
2. Hold the stainless steel sleeve and remove it with the locking cap from
the internal electrode assembly, being careful not to bend the electrode
assembly when doing so.
3. Rinse the internal electrode with distilled water (particularly the tip) and
let it soak for at least 15 minutes. Be careful not to let water get into the
handle.
4. Gently dry the electrode with a soft tissue (Kimwipes). Be sure to dry
thoroughly the at surface at the tip of the electrode. After drying, the
current should stabilize fairly quickly to a low value (e.g., 0 - 20 pA). If
this occurs then the electrode is in good working order.
5. If the electrode is not clean, repeat steps 3 and 4. If necessary the ISO-
HPO-2 can be rejuvenated using WPI #JUV to restore sensitivity of an
old electrode (contact WPI for details).
6. Remove the locking cap from the old sleeve and gently slide it onto the
new replacement sleeve.
7. Dip the internal electrode 1-2 cm into the electrolyte provided in the
ISO-HPO-2 start-up kit; the current should go offscale during this. Using
the MicroFil™ nonmetallic syringe needle (WPI #MF28G67-5) and
1 mL plastic syringe, supplied with the replacement sleeve kit, inject
approximately 100 microliters of electrolyte directly into the new sleeve.
The MicroFil supplied should be less than the length of the sleeve, so
that it will not puncture the delicate membrane at the tip of the sleeve
during injection. If the MicroFil is longer than the sleeve it can be cut to
the correct length.
8. Slowly and smoothly insert the electrode into the sleeve, and screw the
locking cap into the handle. The electrode should be observed to press
gently against the membrane.
9. The current displayed on the meter at this time will be high or offscale.
10. Suspend the tip of the new assembled probe into PBS or similar saline
buffer.
11. After 10-15 minutes the current should no longer be offscale and will
gradually decrease with time. It may take several hours for the sensor
current to reach a low stable value, at which time it will be ready for use.
12. The integrity of the new membrane can be determined by immersing
the probe tip into a strong saline solution (1 M). If the current observed,
after a few minutes in the saline solution, increases dramatically or is
offscale then the membrane integrity is not good and a new membrane
will have to be tted.
13. When the ISO-HPO-2 is not being used it should be stored with the tip
suspended in PBS.
Additional membrane kits (WPI #600012) may be purchased separately.
combination
working / counter
electrode
probe
handle
stainless steel
sleeve
gas permeable
membrane
connection
to meter
locking cap