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How does a test sample differ from a test portion in analytical chemistry?
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In analytical chemistry, the terms test sample and test portion refer to distinct stages in the preparation of material for measurement.1
- Test Sample: This is the material that results from the processing of a laboratory sample. It is the prepared form of the sample from which an analyst will subsequently select a specific amount for an analytical determination.1
- Test Portion: This is the specific, smaller quantity of the test sample that is actually measured or analyzed. The selection of the test portion is a critical step, as its size must be sufficient to ensure it remains representative of the test sample, particularly when dealing with heterogeneous materials.12
While the test sample represents the bulk material ready for final analysis, the test portion is the precise amount—whether weighed or transferred by volume—used to perform the actual measurement.12