Jenway 4510 - Manual (Page 15)

3.6 Sample Measurement
General
Conductivity is a temperature dependent measurement. All substances have a conductivity
coefficient which varies from 1% per °C to 3% per °C for most commonly occurring substances.
The automatic temperature compensation on the 4510 defaults to 1.91% per °C, this being
adequate for most routine determinations.
Conductivity readings varying with temperature may be due to the substances under test having a
coefficient other than the typical value of 1.91% per °C. To eliminate this variation it is necessary to
maintain all samples at the reference temperature by use of a thermostatic water bath or
equivalent.
Adjustment may be made by entering the SETUP menu and selecting COEFF (refer Section 3.2.2).
The reading can then be adjusted to the required value (0.00 to 4.00) by using the keypad.
Sample Measurement
After calibration the measurement of samples is carried out by immersing the cell in the samples,
allowing the readout to stabilise, and recording the result. The cell should be rinsed in deionised
water between each sample to avoid contamination, shaken to remove internal droplets, and the
outside wiped prior to immersion in the next sample.
On completion of sample measurement the cell should be thoroughly rinsed in deionised water.
Storage
Short Term the cell should be immersed in deionised water to keep the plates wetted.
Long Term the cell should be thoroughly rinsed in deionised water, the exterior body
wiped and then stored dry.
NOTE: When preparing the cell for storage the plate area MUST NOT be wiped dry.
When using a dry cell initial stability on re-use may be impaired until the cell
plates become re-wetted.
To obtain optimum performance refer to Section 3.1 - Good Practice Guidelines.
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