Researchers used a low-cost espresso machine — rather than expensive analytical equipment—to detect PAHs in soil. Images courtesy of the American Chemical SocietyMany chemists are familiar with taking trips to the espresso machine while running late-night experiments, but until now these excursions were merely undertaken for the caffeine boost. A group recently reported in the American Chemical Society's Analytical Chemistry, however, that espresso machines can quickly and inexpensively perform some complex chemistry experiments, such as testing for harmful compounds in the environment. 

Polycyclic aromatic hydrocarbons (PAHs) are a class of carcinogenic organic compounds that are ubiquitous in the environment. They are generated by incomplete combustion of materials in forest fires, industrial plants, and waste incinerators. To determine the levels of PAHs in soil and sediment, researchers first extract the compounds from a sample, a step that can take up to 16 hours and requires large amounts of hazardous solvents. Newer techniques that use high temperatures are faster and need much less solvent, but they require pricey lab equipment. So Francesc A. Esteve-Turrillas and colleagues set out to determine whether an espresso machine—which quickly runs hot liquid through a small amount of coffee, or in this case, soil—could efficiently extract PAHs for further analysis. 

The group percolated a soil sample in an espresso machine with a small amount of organic solvent and water. The extracted sample was then analyzed with a standard chromatography procedure to determine the amount of PAHs present. All told, the process takes only 11 seconds. The results from the espresso procedure were comparable to those obtained with certified techniques, but the new process was significantly less expensive and faster. The researchers say that this study shows that espresso makers can be used as low-cost alternatives in chemistry labs. They are currently testing to see whether these machines can extract and analyze pesticides, pharmaceuticals, and detergents in food and environmental samples. 

The researchers acknowledge funding from Spain's Ministry of Economy and Competitiveness and the Generalitat Valenciana (government of Valencia).