3B Scientific pH Sensor User Manual

3B SCIENTIFIC® PHYSICS

pH Sensor U11350

Instruction sheet

04/07 WH

1. Safety instructions

In order to prevent permanent damage to the pH­electrode supplied, it is to be stored exclusively in the
storage solution supplied (pH 4.00/ KCl)!

• Avoid contamination with the following:

Organic lubricants
Artificial resins, macromolecular hydrocarbons
Protein deposits
Dyes
Cleaning agents n aqueous solution
Dlute hydrochloric acid
Alcchols, acetone, ether
Acdic fermentinglutions
Aqueous hypochlorite solutions
Solutions with perchlorate, silver and sulphur

ions

• Do not let the electrode body come into contact

with organic silicone.

• Store the electrode exclusively at temperatures

between +10°C and +35°C

2. Description

The sensor box including the pH-electrode measures
pH-values in aqueous solutions.

A storage solution – NOT a buffer solution – is in­cluded in the scope of delivery

The sensor box is automatically detected by the 3B

TM

NETlog

1 Sensor box
1 pH-electrode
2 Plastic pipettes 1 ml
1 Mini DIN connecting lead 8-pin, 60 cm length

unit.

3. Scope of delivery

1

4. Technical data

Measurement range: pH 0 to pH 14
pH at zero voltage: pH 7.00 ± 0.25
Sensor type: Ag-AgCl combination elec-

trode, gel-filled, non­refillable

Accuracy: pH 0.05 in the range from

20°C to 25°C
Resolution: pH 0.01

Reaction time: ≤

1 s for 95% of final value

5. Operation

• Remove storage bottle from the electrode by

twisting off the lid, then pull the lid off the elec­trode.

• Rinse the lower end in the vicinity of the glass

bulb thoroughly with distilled water, shake off
remaining water and dry with filter paper.

• Move air bubbles in the lower part of the elec-

trode chamber into the upper part by cautiously
shaking them downward.

• Calibrate the electrode. For the procedure, see

section 6 “Calibration”.

• Subsequently, rinse with distilled water, shake off

remaining water and dry with filter paper.

• Conduct measurement.

• After finalising the measurement, rinse the elec-

trode with distilled water and repeat the same
procedure as before the measurement.

• Slide the lid on the electrode and tighten it to the

storage bottle.

6. Calibration

• Connect the electrode to the sensor box, and

connect the sensor box to analog input A of the
3B NETlog

TM

unit, analog input B is suitable for

pH-measurement but not for calibration!

• Wait for the “Probe Detect” function to detect the

sensor.

• Press the (Date/Time ↵) key 4 times until “User

Calibration” appears in the display.

• Start calibration by pressing the (Store L) key.

• Immerse the electrode (after rinsing) in the alka-

line “pH 9.00 buffer solution”.

• Move the decimal points in the display of the (SET

1) with the (Channel I) key towards the left or
with the (Date/Time ↵) key to the right, respec-

tively.

• Increase the displayed value with the (Rate K) key,

or decrease it with the (Store L) key, respectively.

• Set the displayed value to +9.000e+00 and press

(Date/Time ↵).

• Wait for the correction of the measured value,

press (J

ACCEPT) and validate with the

(Date/Time ↵) key.

• Remove the electrode from the “pH 9.00 buffer

solution”, rinse and dry thoroughly, and immerse
in the “pH 4.00 storage solution”.

• Repeat the procedure described above for (SET 2).

• Wait for the “Probe Detect” function to detect the

sensor then conduct the desired measurements.

7. Cleaning the electrode

• After prolonged periods of use, clean the elec-

trode for 1 to 2 minutes in dilute hydrochloric
acid HCl (0.1 mol), then rinse with distilled water
and rejuvenate in potassium chloride KCl (4 mol).

8. Use in experiments

Measurement of common household acids and alkalis
Acid-base titrations
Observation of pH changes in chemical reactions
Testing the influence of photosynthesis on water qual-

ity in aquaria
Examining the influence of acid rain and its neutrali-

sation
Water quality of rivers and lakes

9. Sample experiment

9.1 Qualitative determination of the titration
curve of vinegar

Required equipment:
1 3B NETlog

TM

U11300
1 pH Sensor U11350
1 Measuring cylinder, 100 ml U14205
Household vinegar pH 2.00
Highly dilute sodium hydroxide pH < 14.00

2

• Pour 20 ml of the diluted (1:10) household vine-

gar into the beaker.

• Immerse the pH-electrode (after thorough clean-

ing) in the vinegar solution, all the way to the
bottom of the beaker.

• Select the analogue input A on the 3B NETlog

and activate the experiment (template) for the de­termination of titration curves in the 3B NETlab
software; here, all necessary output adjustments
can be found.

• Conduct and analyse the experiment.

TM

TM

Fig. 1: Qualitative determination of the titration curve of

vinegar

Fig.2: Titration of a vinegar solution and sodium hydrox-

ide NaOH

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com

Subject to technical amendments