Real-time specific surface area measurements via laser-induced breakdown spectroscopy

From healthcare to cosmetics to environmental science, the specific surface area (SSA) of micro- and mesoporous materials or products can greatly affect their chemical and physical properties. SSA results are also widely used to examine source rocks in conventional and unconventional petroleum resource plays. Despite its importance, current methods to measure SSA are often cumbersome, time-consuming, or require cryogenic consumables (e.g., liquid nitrogen). These methods are not amenable to high-throughput environments, have stringent sample preparation requirements, and are not practical for use in the field. We present a new application of laser-induced breakdown spectroscopy for rapid measurement of SSA. This study evaluates geological samples, specifically organic-rich oil shales, but the approach is expected to be applicable to many other types of materials. The method uses optical emission spectroscopy to examine laser-generated plasma and quantify the amount of argon adsorbed to a sample during an inert gas purge. The technique can accommodate a wide range of sample sizes and geometries and has the potential for field use. These advantages for SSA measurement combined with the simultaneous acquisition of composition information make this a promising new approach for characterizing geologic samples and other materials.