Top 10 Best Practice Tips for Moisture Balance Analysis

In many industries, assessing the water content of substances is crucial for determining quality, for example in the food sector where moisture can play a pivotal role in factors like taste, texture, and shelf life. Moisture balances are specifically designed to offer precision in moisture content measurements, by heating the sample while simultaneously measuring mass loss through evaporation. Use the best practice suggestions below to maximise the repeatability and reliability of these instruments.

1. Representative Sample Collection and Preparation:

Ensure the test sample accurately represents the material under analysis. The material should be homogenously mixed and consistent portions should be used for subsequent testing in order to enhance reproducibility.

2. Controlled Ambient Conditions:

Perform sample preparation and analysis in stable ambient conditions that are representative of usual storage conditions. As with all mass-centric analyses, avoid air flows, vibrations, and fluctuations in temperature and humidity, as these can impact the accuracy of results.

3. Appropriate Sample Size:

5-10 grams is a reasonable sample size to use in order to obtain precise and meaningful results. Smaller sample sizes (minimum 0.5 grams) may be acceptable for challenging-to-obtain or expensive materials, with an understanding that this will reduce the precision of results. Ideally, consistency in sample sizes should be maintained for repeatability.

4. Even Distribution and Material State:

When introducing the sample to the pan, it is important to ensure even distribution, with limited piling. Further, it is important to confirm that the material’s distribution and physical state allows for heat absorption and moisture dissipation during the analysis.

5. Immediate Testing and Sample Storage:

The sample should be tested immediately after preparation wherever possible. Samples should be stored in hermetically sealed containers to prevent moisture migration before and between analyses. If a longer storage period is unavoidable, this should always be reported and considered during analysis of the readings.

6. Handling Liquid Samples:

When measuring liquid samples, pastes or slurries; glass fibre pads should be used to provide an inert, porous surface. The sample should be dispersed onto the fibre pad in such a manner as to decrease surface tension and increase overall surface area, shortening analysis time.

7. Clean Aluminium Pans:

Clean aluminium pans should be used for each analysis to avoid residue from previous samples or cleaning agents influencing results. Beyond the sample plate, the moisture analyser should be kept clean and free of debris to ensure accuracy of results.

8. Proper Drying Method:

An appropriate drying method should be developed for the sample. Tools such as the OHAUS MB120‘s SmartGuide feature can be leveraged for support in developing the drying method, reducing the amount of sample needed for method development.

9. Periodic Calibration and Testing:

The moisture analyser should be periodically checked through performance testing. Additionally, ?temperature and weight calibrations will maintain accuracy and reliability in results.

10. Repeat Measurements for Reliability

As with all analysis methods, best practice dictates that samples should be tested a number of times, using various sample amounts to ensure reliance on results.

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