Radiation Measurements 43 (2008) S635 – S638 www.elsevier.com/locate/radmeas The study of the desorption/ionization from the replicas of etched ion tracks V.A. Oleinikov a , D.L. Zagorski b, ∗ , S.A. Bedin b , A.A. Volosnikov a , P.A. Emelyanov a , Y.P. Kozmin a , B.V. Mchedlishvili b a Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia b Shubnikov Institute of Crystallography, Russian Academy of Science, Moscow, Russia Abstract Microstructures obtained as a replica of polymer track membranes could be used for enhancing local electric field near the nanostructured surface. Similar to the well-known effect of electrons emitting from the tops of nanowires (cold cathodes) these replicas can be used for desorption and ionization of molecules in ion source of mass spectrometers. In this work we demonstrated the possibility of ions beam formation from the ensembles of metal microwires prepared by track membrane technique. We used substrate on the base of such ensembles for ejection of ions of biological molecules (polypeptides) under the laser irradiation for the mass analysis by mass spectrometry. We suppose that new type of ion-emitters for mass spectrometers could be developed on the basis of such wires ensembles. © 2008 Elsevier Ltd. All rights reserved. Keywords: Polymer track membranes; Etched tracks; Template synthesis; Microwires; Mass spectroscopy; Desorption and ionization of molecules 1. Introduction Main application of track membranes (TM, or nuclear fil- ters), obtained by high energy heavy ions irradiation of poly- mer films, is filtration. Additionally, TM are known to be the matrixes for template synthesis. It is well known that ion track membranes can be replicated by chemical or electrochemical depositing of different materials into their pores. This is the basic idea of so-called template method of synthesis (Fischer and Spohr, 1983; Flerov, 1984; Mchedlishvili et al., 1993; Martin, 1994; Virk and Kaur, 1995; Virk et al., 1998). The advantage of this technique is the possibility of varying of al- most all growth parameters. Different types of semiconduc- tors, metals, polymers and some other materials in the form of micro- and nanowires were obtained and used. Most com- monly used technique is electrochemical (galvanic) filling of metal into pores of TM. Ensembles of wires, obtained by this way, could be used for taking off heat (effective cooler) and as the catalytic surfaces in chemical reactors. These applications are very promising due to great increase of effective surface of such samples. Other use is connected with the small radius of ∗ Corresponding author. Fax: +7 095 1351011. E-mail address: mic@eimb.ru (D.L. Zagorski). 1350-4487/$ - see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.radmeas.2008.04.018 curvature of the tips of microwires, which play the role of am- plifiers and produce local enhancing of electric field close to microwires surfaces (lightning-rod effect). So they can be used as electron emitters (cold cathodes). In the case of electromag- netic field stimulation (during the laser pulse irradiation) reso- nance mechanism of local field amplification also takes place. We propose here new possible application of such structures as a surface for ejection of ions, i.e. as an ion source in mass spectrometer. It is known that the aim of mass spectrometry is to investigate the molecular composition of the sample by analyzing the mass of separate molecules. The separation of ions of biological molecules was a major problem till recently. Two techniques made the break-through in this field: there were electrospray method (Fenn et al., 1989; Domon and Aebersold, 2006) and the method of matrix- assisted laser desorption–ionization (MALDI) (Kaufmann, 1995; Domon and Aebersold, 2006). The last one is rather simple and gave the possibility of fast sample analyzing. In this method the analyzed substance (the analyte) is just dis- solved in the special substrate (matrix). Then this mixture is deposited on substrate and irradiated by laser in order to eject the molecular ions into analyzing chamber. The matrix in this case must have high adsorption of laser irradiation of this range and have to assist analyte molecules ionization (i.e. give up