WPI ISO-H2S-2, Инструкция по эксплуатации

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ISO-H2S-2
World Precision Instruments 3
Gas permeable membrane –The membrane covers the end of the stainless sleeve
to separate it from the external environment.
Stainless steel sleeve (WPI# 600016, pkg. of 4)–The sleeve houses the sensitive
electrode pair. The sleeve is flanged to properly connect with the locking cap. It must
contain fresh filling solution (WPI# 100084 ).
Working/Counter electrode –This is an internal H
2
S-sensing pair of working and
counter (reference) electrodes.
Locking cap– This cap attaches the sleeve to the probe handle.
When the sensor is assembled (with locking cap and sleeve in place) the internal
electrode should press gently against the polymeric membrane, which will be slightly
stretched . This ensures that the electrolyte diffusion is as thin as possible, minimizing
sensor response time.
NOTE : Once a membrane is stretched it is permanently deformed and cannot be
reused if the sleeve is removed from the electrode.
Additional membrane sleeves are available in packages of 4 (WPI #
600016 ). The ISO-
H2S start-up kit (WPI # 600015 ) also includes replacement membrane sleeves, along
with all the accessories to fill them properly with electrolyte solution.
OPERATING INSTRUCTIONS
Polarizing the Sensor
1. Place the sensor in 0.1M PBS solution
2. Plug it into the free radical analyzer.
3. Turn on the free radical analyzer.
4. Set the poise voltage on the free radical analyzer. On the
TBR4100/1025 , set the
Probe Select switch to H
2
S (150mV).
5. Plug in the ISO-H2S-2 sensor and allow it to polarize up to 12 hours to reach a
stable baseline current of <75000pA before it is used for measurement.
6. During initial polarization the current is typically high, but within an hour it will be-
gin to decrease rapidly. In order to observe this phenomenon, start by setting the
range to 100nA. After several hours the current will fall. The range should always
be set to 100nA, regardless of how low the baseline falls.
7. If the stabilized baseline value exceeds 75000pA, see “Replacing the Membrane
Sleeve” on page 8.
NOTE : This polarization procedure assumes the temperature is 25ºC. At 37ºC the
baseline current is higher.