Raman spectroscopy is well recognized as an analytical tool for the discrimination of similar molecules. Because of this, counterfeit substances such as diluted edible oils and counterfeit prescription drugs can be measured and controlled before they reach the consumer, and hopefully even sooner to reduce unnecessary production costs. Likewise, product tampering such as diethylene glycol in glycerin, melamine in milk powder and methanol-contaminated liquor can be identified and addressed to avoid potential harm to consumers. Similar molecules such as ethanol and methanol, as well as falsely labeled prescription drugs can be analyzed on-site in order to confirm the chemical composition to ensure safety and reliability in the products we use every day.
What makes Raman ideally suited for this particular application over comparative technologies such as FTIR is its nondestructive nature, and ability to measure through optically transparent containers and its insensitivity to interference from water. Portable Raman spectrometers can be used not only for the identification of adulterants, but also for providing quantitative results. This technique can be expanded to other types of adulteration- from water dilution of alcohol and other products, to intentional substitution of prescription drugs with placebos.