Product Manual

©Adam Equipment 2017

8.0 SAMPLE PREPARATION

Sample preparation is the single most important item for accurate results. The sample must be

prepared so the whole of the sample is heated uniformly and the moisture is near the surface of the

material.

For powders no further preparation is necessary. For most other materials the sample should be

ground, chopped, grated or otherwise made as fine as possible. Liquids or paste may need to be

spread onto or sandwiched between glass fibre pads to distribute them evenly and thinly. Some

materials that may splatter as they are heated (oils, butter) may need to be spread on the glass fibre

pads or mixed with dry sand. If a substance is likely to form a surface skin when heated from above

then it should be covered by a pad.

Trial and error is often the only method to find the best method for the material.

When the sample is placed on the weighing pan it should be spread as thin and evenly as possible,

do not compact the material. Ensure enough material is used to assure good repeatability of the

results. Typically samples of 3 to 8 grams are used. Larger sample sizes will usually produce more

accurate and consistent results.

Some materials will require special preparation. For example when testing cheese, if the cheese is

very soft it may be necessary to use dry sand as a buffer material so it does not splatter or form a

skin. To do this it would be necessary to prepare the sand by drying it in an oven until you are certain

no moisture remains. Put the sand on the sample pan and tare the analyzer. Mix the sand with the

cheese so you have smooth mixture, spread this mixture on the sample pan and then do the test.

An alternative to this preparation is to spread the cheese on dry spun glass gauze to assist in

spreading the heat and preventing splatter or skins forming. Remember to tare the analyzer with the

gauze in the weighing pan for accurate results.

Other materials will hold water within them in a way that is not suitable for this type of test. For

example sugar will bind the water to the sugar molecules so strongly that heat will not remove the

water before the sugar is burned.

Some plastics also are not suitable for this type of method due to the very low percent moisture and

the heat required to extract this moisture.