Foil And Tape Serve Raman

A simple method that generates a forest of silver dendrites on aluminum foil turns out to be ideal for creating material to use as a substrate in surface-enhanced Raman spectroscopy, or SERS (J. Am. Chem. Soc., DOI: 10.1021/ja909806t). Since the 1970s, scientists have used metal surfaces to amplify the normally weak signals generated during Raman spectroscopy. Although the mechanism for the enhancement is still debated, researchers have produced numerous variations of substrates using different metals. But many of these processes are expensive and time-consuming. Roya Maboudian, Albert Gutés, and Carlo Carraro of the University of California, Berkeley, tried yet another approach: They soaked squares of aluminum foil in an AgF solution. After silver dendrites formed on the aluminum surface, they collected the pastelike silver and spread it on double-sided Scotch tape. The team used the novel substrate to obtain Raman spectra of 1,2-benzenedithiol, 1-phenylethyl mercaptan, and 2,2´-dithiodipyridine. The dendrite paste can be spread on any surface, the researchers note, making the process “an excellent candidate for analytical SERS control processes or for easy in-the-field measurements.”