These instructions are for samples taken for environmental testing.
The sample sizes, preservation procedures, holding times and conditions for air, aqueous and solid samples are recommendations only.
Base your decision on the nature of the sample, the intended use of the data and the data quality objectives. For example, you can use alternative storage conditions if the analyte stability within a matrix can be demonstrated and data quality objectives are not compromised.
In a given sample, the analyte requiring the most preservation treatment as well as the shortest holding time should dictate the preservation treatment of the overall sample.
General rules for samples
Place in ice immediately after sampling
Cool to <4 °C
Deliver to NMI within 24 hours of sampling
Use ice bricks when dispatching by air and over long distances, and when couriers will not freight ice
Have at least half the recommended holding time remaining when relinquished to NMI
Avoid delivering time-critical samples to NMI late on Friday
Recommendations for specific samples
Each sample type has different recommendations for storage conditions needed to preserve the sample. See our recommended preservation procedures, holding times and conditions for: