Advanced Chlorinated Solvent Detection using Raman Spectroscopy
Researchers at Purdue University have developed a new method to detect the presence of chlorinated solvents in water using Raman spectroscopy. Raman analysis of chlorinated solvents traditionally involves direct monitoring of any of a number of solvent specific vibrational modes, e.g., the 381 cm-1 TCE line. This approach is limited in sensitivity by the inherently weak Raman return of chlorinated solvents. In this new approach, the presence of the solvent can be inferred indirectly by monitoring the OH stretching line of water (3393 cm-1). In experiments performed at Purdue with a 20 uJ laser, the traditional method can only detect TCE at aqueous concentrations as low as 70 ppm. The indirect method, though, is 10x more sensitive and can detect concentrations as low as ~8 ppm at the same laser power, noting that ultimate detection limits are closely tied to employed laser power in the test system. This makes the new method very useful for contaminant plume delineation, warning of contaminant release, or the design of tailored monitoring approaches when water systems have been exposed to chlorinated solvent contamination. This method may have value for analysis of aqueous systems containing other group seven elements such as fluorine, bromine, or iodine.
Highly sensitive and can detect subsurface contaminationInexpensive equipment and low application costsCan be used in lab or field operations
Green Technologies/Clean WaterChemical Processing
Joseph SinfieldPurdue Civil Engineering
United States
None
USA
