SAMPLE TRANSPORTATION AND STORAGE AND PREPARATION PROTOCOLS

evaluates this device for the transportation and

extended storage of samples along with covered

core barrel liners and empty volatile organic analy-

sis (VOA) vials (proposed by U.S. Analytical Labo-

ratory, Kimberly, Wisconsin). Core barrel liners are

open-ended tubes that fit inside a subsurface sam-

pler; after filling by pushing into an previously

undisturbed formation, the liners are covered al-

lowing a bulk sample to be transported and stored.

The En Core sampler and the empty VOA vial

serve as chambers for the transportation and stor-

age of discrete samples. The practices used to as-

sess these sample transportation and storage de-

vices are intended to comply with the current EPA

and ASTM guidance, even though they may not

be implicit to these documents. Furthermore, these

experiments will attempt to determine whether

storage at 12 3C is a favorable method of

sample preservation. A general description of how

the samples would be transported, stored, and

prepared for analysis follows.

SAMPLE TRANSPORTATION AND STORAGE

AND PREPARATION PROTOCOLS

Figure 3. Modified 10-mL syringe and empty VOA vial.

Syringe modified by removing tip and rubber plunger

Core barrel liners

cap. (Commercially available from U.S. Analytical

Subsurface soil samples are usually obtained

Laboratory, Kimberly, Wisconsin.)

with a hollow tube designed to collect an intact

cylindrical core of material. Coring tubes typically

cloth so as not to leave particles on the sealing edge

range in size from 2.5 to 10 cm in diameter, and 25

of the sample preparation/analysis vial. Further-

to several hundreds of centimeters in length. Core

more, the coring tool used for this subsampling

barrel liners fit snugly within these coring tubes

step needs to have a smaller outer diameter than

and come in a variety of sizes and materials (stain-

the opening of the sample vial.

less steel, brass, Teflon, rigid plastics, etc.). Only

core barrel liners made out of metal have been rec-

ommended for transportation and storage of

En Core Samplers

The En Core sampler is available in two sizes

samples for VOC analysis (ASTM D 4547-91). Once

allowing for the collection and storage of either a

filled and returned to the surface, the ends of a

5- or 25-g soil sample. Only the 5-g sampler was

core barrel liner are covered with either a thin sheet

evaluated in this study. This precleaned device,

of Teflon or aluminum foil. To hold these sheets in

composed of an inert composite polymer with

place, plastic caps are pressed over the ends and

Viton O-rings to form vapor-tight seals, is intended

in some cases an adhesive tape is also applied.

for a single use. To use this sampler the coring/

These bulk samplers are transported and stored

at 4 2C prior to the removal of a subsample in

storage chamber is attached to a metal handle (Fig.

4) and, with the plunger in the forward position

preparation for analysis. Subsampling is done

(unsealed), the bottom of this tool is pushed into

through the core ends by (1) removing the cover-

a freshly exposed surface until it is filled. Once

ings, (2) removing a few centimeters of soil, and

the sampler is removed the exterior surfaces are

(3) using a small coring tool, such as a modified

wiped clean and the cap is installed. The sampler

10-mL or smaller syringe (Fig. 3) to transfer a

is then returned to a foil bag and held at 4 2C.

subsample to a VOA vial prepared for either di-

When the sample is prepared for either direct va-

rect vapor partitioning analysis or MeOH extrac-

por partitioning (purge-and-trap or headspace)

tion. After the syringe is removed from the bulk

analysis or MeOH extraction, the sampler is at-

sample, the exterior walls are wiped with a clean