Current trends in nanoengineering are bringing along new
structures of diverse chemical compositions that need to be
meticulously defined to ensure their correct operation. Few methods
can provide the sensitivity required to carry out measurements on
individual nanosubjects without tedious sample pre-treatment or data
analysis. In the present study, we introduce a pathway for the full
elemental identification of single nanoparticles that avoids suspension
in liquid media by means of optical trapping and laser-induced plasma
spectroscopy. We demonstrate spectroscopic detection and
identification of individual Cu nanoparticles of masses down to 73
attograms and report, for the first time, stable optical trapping in air
and manipulation of Cu particles from 25 to 70 nm in diameter. We
found an increase in the absolute number of photons produced as size
of the particles decreased; pointing towards a more efficient excitation
of ensembles of only 7 x exp(-5) Cu atoms in the onset plasma.