Carbon nanoparticles (NPs) from the incomplete combustion of a candle were used as matrix for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). The washed carbon soot NPs (WCS NPs, ~48 nm) exhibit higher laser desorption/ionization efficiency and less background compared with other common metal and carbon matrices. WCS NPs present good reproducibility and high sensitivity in analyzing a wide range of molecules in both positive and negative ionization mode in SALDI-MS. The detection limit of glucose is 1 pmol with WCS NPs as matrix. WCS NPs can be used to quantitatively determine urine glucose, visualize latent fingerprint and image it with SALDI-MS. The UV absorption of WCS NPs and MS spectra analyzed with WCS NPs matrix remain the same after 10 months storage, indicating the good stability of WCS NPs as matrix. Graphical abstractSchematic representation of carbon nanoparticles derived from carbon soot and its application as matrix in SALDI-MS.
Keywords: Carbohydrate; Fingerprint imaging; Quantitation; Stability; Washed carbon soot.