What is a duplicate sample in sampling QA/QC?

What is a duplicate sample in sampling QA/QC?

• A. A sample collected from a different floor.
• B. A second sample collected from a similar surface to assess precision and repeatability.
• C. A sample collected to replace a lost sample.
• D. A sample collected after cleaning.

Answer: (B)

A duplicate sample in QA/QC sampling is a second sample taken from the same surface or a closely similar area to test how consistent the measurements are when you repeat the sampling and analysis. By comparing the two results, you assess precision and repeatability of the method—whether the process yields similar numbers under the same conditions. This is why it’s described as a second sample from a similar surface to assess precision and repeatability. Collecting from a different floor wouldn’t test the same surface’s repeatability, replacing a lost sample isn’t the same as duplicating for quality check, and collecting after cleaning serves a different purpose (evaluating cleanliness), not the consistency of the sampling/analysis.

A duplicate sample in QA/QC sampling is a second sample taken from the same surface or a closely similar area to test how consistent the measurements are when you repeat the sampling and analysis. By comparing the two results, you assess precision and repeatability of the method—whether the process yields similar numbers under the same conditions.

This is why it’s described as a second sample from a similar surface to assess precision and repeatability. Collecting from a different floor wouldn’t test the same surface’s repeatability, replacing a lost sample isn’t the same as duplicating for quality check, and collecting after cleaning serves a different purpose (evaluating cleanliness), not the consistency of the sampling/analysis.