“Standard Operating Procedure for Operating and Calibration of Karl Fischer Apparatus for Moisture Content Determination”

1.0 OBJECTIVE

To define the procedure for the operation of the Karl Fischer apparatus used to determine moisture content in samples.

2.0 SCOPE

This Standard Operating Procedure (SOP) is applicable to the Quality Control department.

3.0 RESPONSIBILITY

The Quality Control Supervisor is responsible for ensuring the proper operation of the Karl Fischer apparatus.

4.0 ACCOUNTABILITY

The Senior Manager of Quality Assurance is accountable for compliance with this SOP.

5.0 PROCEDURE

5.1 Preparation of Karl Fischer Reagent

5.1.1 Take approximately 150 ml of Karl Fischer reagent. Ensure that all glassware used is completely dry to avoid any contamination with moisture, which could affect the reagent’s effectiveness.
5.1.2 Add the Karl Fischer reagent to the reservoir bottle located at the back of the apparatus, and immediately replace the stopper to prevent exposure to moisture.

5.2 Preparation of Methanol

5.2.1 Remove the large rubber cork and add methanol to the moisture beaker until the metal wires of the sensors are fully immersed.
5.2.2 Replace the cork immediately after adding the methanol to minimize exposure to air.

5.3 Sensor and Titrator Setup

5.3.1 Connect the relay leads to the small three-pin socket on the titrator.
5.3.2 Attach the sensor wires to the appropriate socket on the instrument.
5.3.3 Adjust the magnetic stirrer speed to ensure that the sensor wires do not touch the stirrer, and also ensure the sensors remain submerged in the methanol without being exposed to air.

5.4 Dispensing Reagent

5.4.1 Place the dispensing burette on top of the Karl Fischer reagent bottle and secure it properly.
5.4.2 Connect the titrator to the main power supply. The instrument’s home screen will be displayed.

5.5 Stirring and Neutralization

5.5.1 Turn on the stirrer by rotating the stirrer knob on the right side of the instrument.
5.5.2 Adjust the magnetic stirrer speed to ensure the sensor wires do not come in contact with the stirrer or air.
5.5.3 Press the “Start” key. The instrument will begin neutralizing the moisture present in the methanol by adding Karl Fischer reagent.
5.5.4 Once the methanol is neutralized, repeat the process until the Karl Fischer reading for methanol shows zero.

5.6 Sample Testing

5.6.1 Weigh the sample whose moisture content needs to be determined.
5.6.2 Press the “Start” key and add the sample to the methanol for water determination. The Karl Fischer reading will be displayed.
5.6.3 Press the “Smpl” key and input the weight of the sample.
5.6.4 Press the “Enter” key and then press the “%age, PPM, mgH2O” key to display the water content in the sample.

6.0 ABBREVIATIONS

6.1 SOP: Standard Operating Procedure
6.2 QA: Quality Assurance
6.3 QC: Quality Control
6.4 KF: Karl Fischer