Versatile and Fast Onsite Analytical Programs for Today’s High Resolution Site Characterizations

Oral Presentation

Prepared by M. Rossi, M. Greenwald
Cascade Technical Services, 535 Stone Cutters Way, Montpelier, VT, 05602, United States

Contact Information:; 802-229-2194


Over the past decade, site characterization methods have advanced considerably. The need for versatile onsite analytical programs delivering fast analytical results has increased accordingly. Many site investigations cover a range of organic contaminants that are regulated down to low part per billion levels and may be present in soil, rock, groundwater and gas-phase samples. Concentrations of these contaminants can range by orders of magnitude over short distances in the subsurface. Therefore, density of sampling has increased. This is known as high-resolution site characterization (HRSC), wherein onsite analytical programs often provide results faster and at a lower cost. HRSC teams use real-time decision logic, based on the data they receive in the field, to determine where to sample next. Many HRSC programs require onsite laboratory programs that offer fast turn-around times, accommodate large numbers of samples, and achieve ultra-low detection limits for contaminants in various media.

Several analytical techniques based on using a single analytical instrument and a technique known as Solid Phase Microextraction (SPME) have been designed to meet these challenges. SPME is a solventless extraction, concentration and introduction technique using a fiber coated with a variety of extracting phases for different types of analytes. By coupling SPME with state-of-the-art GC/MS systems, a variety of compounds can be quickly and accurately quantitated down to ultra-low levels. SPME/GC/MS techniques often require significantly less sample volume than other methods. A single SPME/GC/MS method can incorporate a set of analytes that, if using conventional methods, would require more than one method.

Through the use of SPME/GC/MS techniques, several analytical methods can be deployed from a single GC/MS instrument for rapid analysis of a variety of organic contaminants in soil, water and gas-phase samples at levels often satisfying regulatory standards. Examples are 1) 1,4-dioxane and 15 other VOCs analyzed down to 1 ug/L in groundwater in less than ten minutes and 2) tetrachloroethene and 1,4-dioxane analyzed in gas-phase samples down to levels that meet most sub-slab screening values.