Direct detection of nicotine and cotinine in dusted latent fingermarks of smokers by using hydrophobic silica particles and MS

Abstract

AbstractSub‐micron sized hydrophobic silica particles doped with carbon black have been employed with latent fingermarks on glass and metal surfaces to develop a simple method for detecting nicotine and cotinine using surface assisted laser desorption/ionisation‐time of flight‐mass spectrometry (SALDI‐TOF‐MS) in positive ion reflectron mode. Dusting of surfaces enables location of marks for conventional identification of details but the particles also act as a laser desorption/ionisation enhancing agent (LDI) equivalent to a standard matrix enhancer 2,5‐dihydroxybenzoic acid used in matrix assisted LDI‐TOF‐MS (MALDI‐TOF‐MS). The method has been applied in the analysis of smokers' latent fingermarks on metal and glass surfaces. The metal surfaces were analysed following direct MS analysis of the pre‐dusted prints, while the glass surfaces were analysed following lifting using commercial tape, and then MS analysis of these pre‐dusted prints. In all cases of smokers, a major peak at m/z 163 (nicotine+1) and a less intense peak at m/z 161 (possibly anatabine+1) were found in the prints and in some cases additional peaks at 177 (cotinine+1) and 199 (possibly cotinine+Na) were observed. The presence of nicotine and cotinine in smokers' marks was confirmed using SALDI‐TOF‐MS‐MS following high energy collision‐induced dissociation when characteristic fragmentation patterns were observed for each compound. Copyright © 2009 John Wiley & Sons, Ltd.