Synthesis and analytical applications of photoluminescent carbon nanodots

We have developed a simple approach for the preparation of carbon nanodots (C-dots) from coffee grounds. As-prepared C-dots have an average diameter of 5 ± 2 nm, of which quantum yield is 3.8%. We have validated the practicality of C-dots for cell imaging and surface-assisted laser desorption/ionization-mass spectrometry (SALDI-MS) of angiotensin I and insulin.