Solid-Liquid Extraction

Source: Laboratory of Dr. Jay Deiner — City University of New York

Extraction is a crucial step in most chemical analyses. It entails removing the analyte from its sample matrix and passing it into the phase required for spectroscopic or chromatographic identification and quantification. When the sample is a solid and the required phase for analysis is a liquid, the process is called solid-liquid extraction. A simple and broadly applicable form of solid-liquid extraction entails combining the solid with a solvent in which the analyte is soluble. Through agitation, the analyte partitions into the liquid phase, which may then be separated from the solid through filtration. The choice of solvent must be made based on the solubility of the target analyte, and on the balance of cost, safety, and environmental concerns.

1. Extraction of Adsorbed Organics from Soil

Place 20 g of soil in a clean, dry wide-mouth Pyrex dish in a 50 °C oven and dry for a minimum of 12 h. After drying, remove the soil from the Pyrex dish and grind to a uniform powder using a mortar and pestle. Weigh 5.00 g of the soil and place it into a clean, dry round-bottom flask (100 mL in size). To the flask, add 15 mL of n-hexane. Place flask in an ultrasonic bath, and sonicate for 60 min.

2. Sep

A soil sample was collected from a Brownfield site similar to one in Sewickley Pennsylvania, as shown in Figure 1. Brownfields, as defined by the United States Environmental Protection Agency (U. S. EPA), are real property, where the expansion, redevelopment, or reuse may be complicated due to the potential presence of hazardous contaminants. The soil was collected from the Brownfield site using a soil sampler, as shown in Figure 2.

The pollutant of

The general solid-liquid extraction procedure is applicable to a range of fields from environmental monitoring (shown in this video) to cosmetics and food processing. The critical issue is to pick a solvent that effectively dissolves the analyte. With minimal changes in solvent, the sample preparation method in this video can be used to extract any of a broad range of semivolatile environmental contaminants that partition primarily on soils and sludges.

Examples of

US Environmental Protection Agency. Ultrasonic Extraction, Method 3550C. Washington: Government Printing Office (2007).
US Environmental Protection Agency. Organochlorine pesticides by gas chromatography, Method 8081B. Washington: Government Printing Office (2007).
Madenjian, C. P., Rediske, R. R., O'Keefe, J. P., David, S. R. Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey. J. Vis. Exp. (90), e51496, (2014).
Chatterjee, S., Sarkar, S., Oktawiec, J., Mao, Z., Niitsoo, O., Stark, R. E. Isolation and Biophysical Study of Fruit Cuticles. J. Vis. Exp. (61), e3529, (2012).
Mathews, S. L., Ayoub, A. S., Pawlak, J., Grunden, A. M. Methods for Facilitating Microbial Growth on Pulp Mill Waste Streams and Characterization of the Biodegradation Potential of Cultured Microbes. J. Vis. Exp. (82), e51373, (2013).

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