Which statement best describes the purpose of chain-of-custody in ambient sampling?

• A. It records who collected and handled the sample to ensure traceability
• B. It describes the chain of custody in a way that governs data interpretation
• C. It provides the analytical method used
• D. It determines the sampling duration

Answer: (A)

Chain-of-custody is the documented history of a sample from collection to analysis, showing who collected it, who handled it, when and where transfers occurred, and signatures that authenticate each step. In ambient sampling, this record ensures the sample’s integrity and traceability, proving that the sample hasn’t been replaced or contaminated and that results belong to the specific sample and event. This defensibility is essential for regulatory decisions and data quality, especially if the sample is ever questioned or audited. It doesn’t specify the analytical method or the duration of sampling—that information comes from method documentation and the sampling plan—nor does it govern how results are interpreted. The main purpose is to establish and maintain the chain of possession and custody of the sample.