title: Desorption electrospray ionization mass spectrometry of DNA nucleobases: implications for a liquid film model.
abstract: Desorption electrospray ionization (DESI) mass spectrometry has been implemented on a commercial ion-trap mass spectrometer and used to optimize mass spectrometric conditions for DNA nucleobases: adenine, cytosine, thymine, and guanine. Experimental parameters including spray voltage, distance between mass spectrometer inlet and the sampled spot, and nebulizing gas inlet pressure were optimized. Cluster ions including some magic number clusters of nucleobases were observed for the first time using DESI mass spectrometry. The formation of the cluster species was found to vary with the nucleobases, acidification of the spray solvent, and the deposited sample amount. All the experimental results can be explained well using a liquid film model based on the two-step droplet pick-up mechanism. It is further suggested that solubility of the analytes in the spray solvent is an important factor to consider for their studies by using DESI.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Qiu
authors.forename: Hai
authors.initials: H
authors.lastname: Luo
mesh_terms: D000225:Adenine / Q000737:chemistry*; D003596:Cytosine / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011312:Pressure; D012995:Solubility; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013941:Thymine / Q000737:chemistry*
chemical_list: D006147:Guanine; D003596:Cytosine; D019904:Polymethyl Methacrylate; D000225:Adenine; D013941:Thymine