3B SCIENTIFIC 1000553 Talimat Sayfası - Sayfa 2

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5. Operation

5.1 General instructions



Rinse the lower end of the electrode

thoroughly with distilled water, shake off

any remaining water and dry with filter

paper.



Select the expected measurement range

for

the

test

liquid

appropriate measuring range button.



Immerse the end of the electrode with the

slot at its tip into the liquid to be tested.

Important: the graphite cell surfaces must

be completely immersed in the test liquid.



Stir the liquid gently with the electrode, and

after 5 to 10 seconds read the measured

value.



When

switching

temperature of the test liquid, the chosen

measuring range button must be held

down for at least 2 seconds.



Wait for a new display to appear on the 3B

unit ("Probe Detect") and read

NETlog

off the temperature.



Press the appropriate measuring range

button again to return to conductivity

measuring mode.



Before making another measurement in a

different liquid, wash the electrode again in

distilled water and repeat the steps

described earlier.



The measurement system is suitable for a

temperature range from 15°C to 35°C. The

calibration temperature is about 25°C.

5.2 Calibration

The electrode is supplied pre-calibrated and

ready for use. Recalibration can only be

carried out at present by the manufacturer 3B

Scientific GmbH.

5.3 Cleaning and care of the electrode



If electrodes get polarised or dirty they

must be cleaned using hot water and a

mild detergent.



Organic substances should be removed

with acetone. Algae, bacteria, mould or

mildew should be removed with a solution

of sodium hypochlorite.



Do not use abrasives or objects that can

scratch the surface.



Finally, wipe the electrode with a cotton

cloth.

pressing

the

over

show

the

6. Experimental applications

Distinguishing

substances with ionic or molecular structures

in liquids, e.g. dilute solutions of acids and

alkalis.

Demonstrating the direct relationship between

conductivity and ion concentration in liquids.

Measuring ion concentrations in unknown

solutions.

Measurements

photosynthetic processes in a basin containing

aquatic plants, and observing the simultaneous

reduction of bicarbonate ion concentration.

In-situ measurements of total quantities of

dissolved solids (TDS, in mg/l) in lakes or

streams.

Observing rates of chemical reactions involving

the uptake or release of a conducting

substance.

Conductivity changes in titrations with two

substances in stoichiometric quantities.

Measurements of the rate of diffusion of one

type of ion through a membrane (osmosis).

Measurements

dissolved solids in an aquarium containing

aquatic plants and animals such as fish.

Distinguishing between photosynthesis and

respiration

7. Sample experiments

The increase in the conductivity of distilled

water when common salt is added.

Equipment required:

1 3B NETlog

@ 230 V

1 3B NETlog

@ 115 V

1 3B NETlab

1 Conductivity sensor

1 Glass beaker, 600 ml,

shallow form

1 Set of Scout Pro

electronic scales, 200 g

1 Carton of table salt (500 g approx.)

1 Petri dish

1 Teaspoon

300 ml distilled water



Pour 300 ml of distilled water into the

beaker.



Immerse the conductivity electrode (which

must first have been thoroughly cleaned) in

the water so that it reaches the bottom of

the beaker.

qualitatively

between

conductivity

and

1000540

1000539

1000544

1000553

1002872

1009772

for

total