Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:4:p8
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 4 (pt 8/12)
Character Range: 759657–762439

and sub-sample according to the procedures given below.
If soils are difficult to sample, (for example, highly compacted or hard clays), it is recommended that a minimum of three core samples be placed into pre-weighed 40 mL glass VOA vials marked at a level corresponding to the required sample weight for analysis. One sample may be used for preliminary screening analysis if desired, the others for analysis by purge and trap.

Once samples are taken, ensure that jar or vial closures are free of soil particles before capping. Samples should be sealed and transported to the laboratory as soon as practicable, under suitable cooling aids (preferably ice bricks or in a refrigerated container) to ensure samples start cooling as soon as possible, and they should be stored in a refrigerator (≤6°C) until analysis.

Note 1: The 40 mL VOA vials are particularly effective in conjunction with modified closures (US EPA SW-846, Method 5035), or suitably designed purge and trap instruments, which allow the vial to function as a sparge vessel for purge and trap analysis. This means there may be no need to open the vial to prepare an analysis sample.

Note 2: Using larger containers may be more convenient and possibly result in fewer analyte losses where removal of test sub-samples is required (Ilias & Jaeger 1993).

Note 3: While immersion of samples into methanol on-site is effective in preserving volatile organics (Lewis et al. 1991), such a practice may not be practicable or permissible according to local laws. Handling volatile chemicals in the field, and transporting them, can have work health and safety implications and is not generally recommended unless so advised by the analyst to meet a specific requirement.

    4.3.2         Preliminary screening analysis
Laboratories may perform a preliminary screen analysis of soils to prevent contamination of purge and trap equipment by samples with a high contaminant load. This is done by:
    * methanol extraction of a core sample in a 40 mL VOA vial. (Methanol is added with a syringe through the septum cap. A portion of the methanol extract is analysed by purge and trap or other method.)
or
    * headspace analysis (US EPA SW-846, Method 5021)
or
    * hexadecane extraction (US EPA SW-846, Method 3820)
or
    * rapidly removing a core sample from a chilled 125 mL/250 mL jar sample and transferring to a vial for analysis as in methanol extraction or headspace analysis above.
After sub-sampling, immediately reseal jar and return to refrigerator storage (≤6ºC).

If analysing whole 40 mL vial samples, note pre-sample weight beforehand and subtract vial weight to determine sample mass.

If screening results indicate a low analyte level suitable for purge and trap analysis, perform this using a second 40