Ocean Optics has shown how highly-sensitive, trace-level Raman spectroscopy measurements can detect concentrations of insecticide that are less than a fiftieth of the level judged harmful to honeybees.
Using a real-world example related to the problem of honeybee population decline, the company demonstrated the power of RAM-SERS-SP Surface-Enhanced Raman Spectroscopy substrates' proprietary gold-silver nanosponge alloy.
Recent high rates of honeybee loss have been investigated by US government regulators and other researchers. According to ongoing US Environmental Protection Agency (EPA) studies, the insecticide imidacloprid has been identified as a threat to commercial honeybee colonies, with the agency citing traces at concentration levels greater than 25 ppb as likely harmful to honeybees.
To test the effectiveness of Ocean Optics substrates in detecting imidacloprid at these harmful trace levels, Ocean Optics scientists set up a lab experiment using the company's gold nanoparticle and gold-silver nanosponge SERS substrates.
In the test, the gold-silver nanosponge SERS substrates delivered the best results, detecting imidacloprid concentrations as low as 0.4 ppb (well within the 25 ppb concentration rate cited by the EPA as harmful to bees). The substrates high sensitivity and low background noise made it easier to discern Raman peaks at these very low-concentration levels.