Sample Collection and Preservation Guidelines

Preservatives must be added in the field at the time of sample collection unless the glassware is already pre-preserved. Preservatives should be recorded on the Chain-of-Custody form in the "Remarks" column on a per sample basis. For certain methods and parameters, the laboratory verifies upon receipt that the sample pH falls within an acceptable range. Improperly preserved samples or samples with pH values outside of the specified range are noted in the sample receiving documentation. The client is contacted and given the option of re-sampling, directing the laboratory to preserve the sample in-house, or processing the sample as it was received. To document the action taken, a Quality Assurance Notice is included in the data report for any occurrence.

Bottles are pre-preserved in-house or, in the case of volatile vials, purchased pre-preserved. Bottles are pre-preserved prior to shipment unless otherwise directed by our clients. Individually packaged EnCore™ sampling devices are provided for collection of 25 gram and 5 gram volatile soil samples for use with Method 8260B and certain methanol preserved TPH analyses.

It is highly recommended not to open bottles until samples are ready to be added-this prevents contamination. It is also important not to rinse the bottles prior to sample collection. Rinsing may contaminate them and remove preservative. Some states may require that non-preserved containers be rinsed with sample water before collection.

When obtaining aqueous samples for the determination of volatile organics, the collector should ensure the absence of headspace by filling the 40-ml bottle to the top. This procedure should produce a positive meniscus across the surface of the vial. The Teflon-lined septum should be placed gently over the sample surface, with the Teflon side down, and the top screwed firmly on over the septum. A proper seal should be verified by inverting the sealed bottle and gently tapping on the sides with your finger, ensuring that no air bubbles appear.

The collector should designate which samples are to be used for Quality Control. For these designated samples, the recommended sample weight or volume should be doubled. If sufficient sample is not available to the laboratory, QC requirements may not be achievable. Excess sample volume will unnecessarily increase shipping costs.

A "wet ice slurry" is ideal for sample collection and the use of blue ice is discouraged and not allowed by some state certifying bodies. Florida requires samples be cooled on wet ice to 4^oC before packing. If you must use blue ice, freeze in a standard freezer for at least 12 hours and no more than 18 hours prior to sampling. Do not freeze the blue ice using dry ice. This freezes your sample and breaks bottles. It is also important not to freeze the sample itself.

Our Project Managers work with our clients to quickly determine the number and types of bottles needed to fill a request. All glassware supplied for sample collection is purchased pre-cleaned and certified from the vendor. The vendor also provides results of analyses using low detection EPA methods to certify the glassware is free of contaminants. Certificates of analysis are made available upon request.

A Coleman/Igloo-style cooler is the preferred sample collection container and is these are provided to customers when they request that glassware be shipped to them. These coolers aid in maintaining sample temperature from the field to the lab.

Shipping to the sampling site by ground transportation is included in the sample analysis cost. CompuChem requires a minimum of three days advance notice for glassware orders so that UPS ground shipment may be utilized. Shipping costs for overnight or second day air transportation of bottles is billable.