Evenly-sized silver colloids have been produced in a single simple step

Libor Kv?tek’s love of photography led him to study silver colloids, which have been used to make photographs for more than 150 years. Silver colloids are also useful in catalysis and have antimicrobial properties.

Now Kv?tek and colleagues at Palack? University in the Czech Republic have shown that these colloids can be made by reducing a silver-ammonia complex with sugar, in a simple one-step procedure like the ’silver mirror test’ for aldehydes, familiar to chemistry students.

By varying the sugars used in the reduction and the concentrations of ammonia, the researchers could tune the size of the silver colloids produced.

These evenly-sized colloids can be used in surface-enhanced Raman spectroscopy (SERS).

SERS is so sensitive that it can identify a single molecule on a silver colloid’s surface, and it can be used as a selective sensor for biologically important molecules.

Carol Stanier