What is the minimum sample amount for vial sampling?

• A. 1 mL
• B. 0.5 mL
• C. 0.1 mL
• D. 5 mL

Answer: (A)

In vial sampling, you need enough liquid to handle reliably and to keep the sample representative. A minimum of about 1 mL provides enough material for accurate pipetting or autosampler transfer, allows for possible duplicates or confirmatory tests, and leaves proper space in the vial for sealing and any required headspace considerations. Volumes smaller than this tend to introduce more transfer variability and a greater risk of sample loss or evaporation, while a larger amount isn’t typically needed for standard analyses and just adds handling complexity.