SOP for Operation and Calibration of Conductivity Meter

1.0 PURPOSE

To lay down the procedure to perform the Operation and Calibration of the Conductivity meter.

2.0 SCOPE

It is applicable to the Instruments installed in the Quality control department.

3.0 RESPONSIBILITY

QC Analyst / Microbiologist

4.0 ACCOUNTABILITY

Head of Department

5.0 PROCEDURE

5.1 Operation of the conductivity meter

5.1.1 Switch on the main supply and press the ON/OFF button of the conductivity meter to switch on the meter and switch off the meter.
5.1.2 For automatic temperature compensation (ATC). Simply attach the conductivity \TDS electrode to the meter ensure that the ATC mode has been selected in the setup menu The ATC indicator will light on the LCD.
5.1.3 Note: If the conductivity /TDS electrode is not properly attached to the meter or it has been damaged, the ATC indicator will blink and the temperature display will show “Ur”.
5.1.4 Rinse the electrode with de-ionized or distilled water before use to remove any impurities adhering to the electrode body. Shake or air dry. To avoid contamination or dilution of your sample rinse the electrode with the small volume of your sample.
5.1.5 Press ON to switch on the meter.
5.1.6 Dip the electrode into the sample.
5.1.7 When dipping the electrode into the sample, take care to ensure that the liquid level is above its upper steel band. Stir the electrode gently in the sample to create a homogeneous sample.
5.1.8 Allow time for the reading to stabilize. Note the reading on the display

5.2 Calibration of the conductivity meter

5.2.1 Before starting calibration makes sure that the instrument is in the correct measurement mode.
5.2.2 Wash the electrode with deionized water after and before use and Store it dry.
5.2.3 Change the buffer after one week or when required , and record the details.
5.2.4 Perform the calibration using a standard buffer of 1413 µS and record the details.
5.2.5 Press the mode key to select conductivity mode the conductivity indicator appears in the upper right hand corner of the display.
5.2.6 Rinse the electrode thoroughly with deionized water or a rinsing solution do not wipe the probe this causes the electrostatic charge on the glass surface.
5.2.7 Dip the electrode into the calibration buffer, the end of the probe must be completely immersed into the sample. Stir the probe gently to homogenize the sample.
5.2.8 Press CAL/MEAS key to enter conductivity calibration mode. The CAL indicator will be shown. The primary display will show the measured reading while the smaller secondary display will indicate the conductivity standard buffer solution.
5.2.9 Press HOLD/ENTER key to confirm calibration. The meter is now calibrated to the current buffer.
5.2.10 Rinse the electrode with de-ionized water or a rinse solution and store it dry.

5.3 Electrode care and maintenance

5.3.1 Keep the conductivity electrode clean, the electrode twice, and gently swirl it while you take readings. For best accuracy soak a dry electrode for at least for 5 to 10 minutes.
5.3.2 Never scratch the bands with a hard substance.
5.3.3 Do not strike the electrode against any hard surface.
5.3.4 Do not immerse the electrode in an oily substance.
5.3.5 Clean the electrode thoroughly by stirring it in a mild detergent or isopropyl alcohol.
5.3.6 Wipe the electrode with soft tissue paper clean the electrode with tap water and recalibrate before use.

6.0 ABBREVIATION

SOP - Standard operating procedure

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