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 4oC 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.

Guidance on EPA SW846 Method 5035

We have the capabilities and supplies to provide any of the Method 5035 options. However, because of some disadvantages, our laboratory favors the use of disposable EnCore™ samplers, with zero headspace design, for the collection of soil samples for volatile analysis. The EnCore™ sampler is available in 5g and 25g sizes. Some regulatory agencies may mandate using the 5g size. Three 5g EnCore™ samplers, with a 2 ounce jar for percent moisture, would be required per sampling site to include the following:

• A 5g aliquot for the sample analysis
• A 5g aliquot as a back-up for the sample analysis
• A 5g aliquot for a methanol extraction, which would be used for screening and/or a high concentration analysis
• A 2 oz. aliquot for a % moisture determination

In most cases, the methanol aliquot (containing surrogates) will be used for screening purposes. Based on those results, other tests will be performed. Once aliquots of the soil sample, taken from the EnCore™ sampler, are added to vials containing preservative, the remainder of the 14 day holding time is available.

Advantages of use of the EnCore™ include the following points:

• No need to take or use a balance in the field
• No exposure of field personnel to corrosive sodium bisulfate or flammable/toxic methanol
• No additional shipping paperwork or cooler labeling
• No need to use the costly closed system purge and trap vials in the field
• No chance of volatile sample container breakage during shipment
• Significant decrease in man-hour requirements to complete the field sampling efforts

Sample Records

Three types of labels will be supplied. Included will be: a return label, Custody seals, and a sufficient number of sample identification labels. On the sample identification labels, please indicate the appropriate analyses and your sample identification. Affix these labels to the appropriate sample containers.

A Chain-of-Custody record and client information sheet are also provided. The analysis code ordered as well as the volume requirements will be stated on the client information sheet. Provide as much identifying information about your company and your sample identity as possible. We process thousands of samples a year, often from several plants within several divisions of the same company, all at the same time. If you have any other questions, please call your customer service representative directly or through our toll free number @ 1-800-833-5097.