Handling and Preservation Resources
The following table gives an indication of the sample container and preservatives required for a variety of parameters.
Download Preservation and holding times
Handling and Preservation of Samples for Soil Testing
Handling and Preservation of Samples for Water Testing
Waters are susceptible to change as a result of physical, chemical or biological reactions which may take place between the time of sampling and the analysis. If precautions are not taken, at the time of sampling, changes may occur rendering analytical data unrepresentative.
Changes may occur due to:
|Consumption of certain constituents by bacteria, algae etc.;|
|Oxidation of certain compounds by the dissolved oxygen in the sample;|
|Precipitation from the liquid, e.g. calcium carbonate, aluminium hydroxide;|
|Loss into the vapour phase;|
|Absorption of carbon dioxide from the air, changing the pH value;|
|Adsorption of metals and certain organic compounds on to the container's surface;|
|Depolymerisation of polymerised products and vice versa.|
These changes will be affected by the storage temperature, exposure to light, the nature of the container used and the time between sampling and analysis. In adverse conditions, changes can occur in just a few hours.
Fortunately, preservatives are available to prevent these changes. However, it must be kept in mind that methods of preservation are less effective for heavily contaminated samples than those with light contamination.
Please follow the instructions below when sampling water:
|Always fill sample containers to the brim and stopper them so that no air is left above the sample.|
|Use an appropriate container. For example. polyethylene bottles should not be used for hydrocarbons, since adsorption on to the bottle's surface is likely to occur.|
|Glass containers are suitable for most determinations. Brown bottles should be used, since this will reduce photosensitive reactions by a considerable extent.|
|Containers must be clean. Whilst this may seem obvious, scrupulous cleanliness is important due to the low detection levels now being adopted.|
|Samples should be kept at an adequate temperature between 2- 5 degrees Celsius (°C). Keeping the sample in ice, a refrigerator or cool bag with ice packs is adequate. This method, however, is not suitable for long-term storage.|
|Generally filtration is achieved by use of 0.45 micron filter paper.|
Please download the preservation and holding time brochure for detailed information.
Handling and Preservation for Potential Acid Sulphate Soil Testing (SPOCAS)
A minimum of 200g should be collected in zip-lock bags to minimize contact with air. Large shells, wood, charcoal and stones should be removed in the field, but biological remnants such as roots should not be removed. Deliver to lab immediately or freeze samples.
Download Acid Sulphate Soil Testing brochure for more information.
Handling and Preservation of Asbestos Samples
Special precautions are required for sampling this material. Disturbing lagging that contains asbestos is extremely dangerous and should only be carried out by qualified individuals.
The instructions below should be considered the minimum precautions you should take when sampling material suspected of containing asbestos. If in doubt, please contact us.
|Dampen or wet the material to be tested for asbestos.|
|Before using pliers or any other available tool, place a baby-wipe to protect the inside edges of the tool - If the inside of the pliers is "ribbed" or textured, this precaution helps limit the possibility of parts of the sample getting stuck in these textured areas.|
|Break off a small thumbnail sized sample.|
|Place the sample into a sealable polythene bag, such as a sandwich bag.|
|Place the bagged sample into another sealable bag.|
|Attach a label to the bag that identifies the sample type and sample location. An example of sample type is fibre cement and sample locations might include ceiling tiles or fireboards.|
|Include your name, address, email address and contact number with your sample being tested for asbestos.|
|Seal the exposed edge of the sample being tested for asbestos with duct tape or paint to avoid fibre release.|
|Clean any tools used with a wet paper towel or baby-wipes and place in a separate bag to the sampled material.|
|Send your double-bagged samples by courier, mail or alternatively bring the sample to one of our Envirolab Services office locations or laboratories.|
Download Asbestos Testing brochure.
If the material you are considering sampling looks to have a sprayed finish, particularly if it is insulating material on pipework, boilers or celings, do not sample this yourself!