Anionic gold ions desorbed from gold nanorods and nanospheres

The desorption and ionization of gold anions and cations from gold nanorods and nanospheres were investigated using a matrix-assisted laser desorption/ionization mass spectrometry instrument. The signal intensities of the gold anions from nanorods with a volume of 4.8 × 10³ nm³ were about 28 times larger than the signal intensities of gold anions from nanospheres of similar volume. Gold cations did not show a remarkable difference depending on the nanoparticles' shapes. The unique desorption behavior of gold anions suggests their potential as reporter ions in mass spectrometry.