Sampling for volatile organic compounds (VOCs) has always been a delicate and precarious process, regardless of the matrix in question. Written methods, and the samplers following them, must face the challenge of how to capture these elusive compounds- vulnerable even to the slightest amount of handling- without disturbing and volatilizing them into the open air.
Originally published in 1997, EPA method 5035 provided a method for sampling soils for VOCs that could circumvent the easy volatilization of these compounds. Prior to the method’s publication, solid samples intended for VOC analysis were easily compromised by environmental and human factors. With its unique approach to minimizing VOC evaporation and phase change, method 5035 has steadily grown in popularity, and is becoming the de facto standard within the environmental services industry.
Today, a number of commercially-produced sampling kits for EPA method 5035 are available on the market, and generally consist of:
- 1 plunger-type sampler for collecting a 5-gram soil aliquot
- 1 40mL VOA vial preserved with Methanol
- 3 40mL VOA vials preserved with Sodium Bisulfate
- 1 centrifuge tube or soil jar for use in Percent Solids calculations
Using the plunger-type sampler for sample collection, a 5 gram sample of soil can quickly be taken from a boring and placed into a VOA vial containing a solution of sodium bisulfate (for samples with low-levels of VOCs) or methanol (for samples with high levels of VOCs). An accompanying second vial or jar is then filled with additional soil for use in calculation of sample results by dry weight. Magnetic stir bars, already placed within the VOA vials, allow for laboratory analysts to process the final sample aliquots without ever needing to disturb the sensitive sample material within.
Part of the method’s continuing appeal is the flexibility it offers sampling personnel in the field. Circumstances pertaining to both high concentration and low concentration samples were taken into account during method development, and samples can easily be frozen for extended storage if they cannot be shipped to a laboratory right away (a welcome change from the tight holding times common in VOC sampling).
While EPA method 5035 itself is something of a small miracle, acquiring the proper sampling materials can be a slightly different story. Typical commercially-produced sampling kits can sometimes be difficult to procure in today’s challenging economic environment, and are assembled in bulk by their manufacturers, leading to inconvenient expiration dates that can clash with your sampling plan.
Enthaply’s EPA 5035 sampling kits are made to order from the highest quality laboratory supplies available, to the specifications of your project, in as great or small of a quantity as your project may require.
Are you thinking of incorporating EPA method 5035 into your next project? If so, please contact us here.