https://www.ciciai.com/thread/ad261c7846d17
https://www.ciciai.com/thread/a5a0ec5d83fda
https://www.ciciai.com/thread/acee849ebb4df
https://www.ciciai.com/thread/a995cc816ab4f
https://www.ciciai.com/thread/af5c2d7fea911
https://www.ciciai.com/thread/ac2001e768515

Draft for ISO 6321:2002 – Determination of Cloud Point of Oils and Fats

1. Apparatus and Reagents Preparation

1.1 Apparatus:

Cloud Point Apparatus: A jacketed test tube with a liquid bath or refrigeration system.

Thermometer: Calibrated to measure temperatures accurately near the cloud point.

Stirring Rod: For mixing the sample before testing.

Water or Refrigerant Bath: Maintains the desired cooling rate.

Illuminated Background: To enhance visibility of cloud formation.

1.2 Reagents:

Sample Oil or Fat: Prepared according to the method.

Dry Ice or Cooling Medium: If required for rapid cooling.

Cleaning Solvent: Such as hexane or acetone to clean glassware.

2. Practical Test Procedure Workflow

Sample Preparation:

Ensure the oil or fat sample is clear and homogenous before testing.

Heat the sample to a specified temperature (usually 10°C above the expected cloud point) to remove any crystalline material.

Filling the Test Tube:

Transfer a specified volume (as per the standard) into the jacketed test tube.

Place the thermometer at the center of the sample.

Cooling Process:

Start cooling at a controlled rate.

Stir gently to prevent supercooling effects.

Observe the sample against an illuminated background.

Cloud Point Determination:

Record the temperature at which a cloud or haze appears.

Confirm by allowing the sample to warm slightly, ensuring the cloud disappears and reappears upon cooling.

Recording and Reporting:

Note the cloud point temperature to the nearest 0.5°C.

Repeat if necessary for confirmation.

3. Calculation

Cloud point is directly determined by observation and does not require mathematical calculation. The result is reported as the first visible formation of cloudiness in the sample.

4. Reporting Limits and Units

Reporting Unit: °C (Celsius).

Lower and Upper Limits: As defined by the product specifications, e.g., vegetable oils may have cloud points around 10-20°C, while animal fats may be much higher.

5. Testing Checklists

Before Testing:
✔ Sample is homogenous and properly prepared.
✔ Test tube and thermometer are clean and dry.
✔ Calibration of thermometer is verified.
✔ Cooling bath is at the correct temperature.

During Testing:
✔ Sample is stirred gently to avoid supercooling.
✔ Observation is made against an illuminated background.
✔ Temperature is recorded precisely at the first sign of clouding.

After Testing:
✔ Cloud point result is verified by reheating and cooling again.
✔ All data are recorded correctly in the logbook.
✔ Glassware and equipment are cleaned for the next test.

6. Method Precision

Repeatability (Single Laboratory): ± 0.5°C.
Reproducibility (Between Laboratories): ± 1.5°C.
Sensitivity: Depends on sample composition and instrument calibration.

This draft provides a structured approach to performing the cloud point test based on ISO 6321:2002. Let me know if you need further customization.