Very high resolution mass spectrometry of HCN polymers and tholins V eronique Vuitton, * a Jean-Yves Bonnet, a Maeliss Frisari, a Roland Thissen, a Eric Quirico, a Odile Dutuit, a Bernard Schmitt, a L ena Le Roy, b Nicolas Fray, b Herv e Cottin, b Ella Sciamma-O’Brien, c Nathalie Carrasco c and Cyril Szopa c Received 2nd March 2010, Accepted 17th April 2010 First published as an Advance Article on the web ????? DOI: 10.1039/c003758c HCN polymers are complex organic solids resulting from the polymerization of hydrogen cyanide (HCN) molecules. They have been suspected to contribute to the refractory carbonaceous component of comets as well as the distributed CN sources in cometary atmospheres. Titan’s tholins are also organic compounds produced in a laboratory setting but result from the complex chemistry between N 2 and CH 4 induced by UV radiation or electric discharges. Some of these compounds have optical properties in the visible range fairly similar to those of Titan’s aerosols or those of the reddish surfaces of many icy satellites and small bodies. It has been proposed that HCN polymers are constituents of tholins but this statement has never received any clear demonstration. We report here on the comparative analysis of tholins and HCN polymers in order to definitely establish if the molecules identified in the HCN polymers are present in the tholins as well. First, we present a global comparison of HCN polymers with three kinds of tholins, using elemental analysis measurements, infrared spectroscopy and very high resolution mass spectrometry of their soluble fraction. We show that the chemical composition of the HCN polymers is definitely simpler than that of any of the tholins studied. Second, we focus on six ions representative of the composition of HCN polymers and using mass spectrometry (HRMS and MS/HRMS), we determine that these tholins contain at best a minor fraction of this kind of HCN polymers. Introduction Tholins and HCN polymers are complex polymeric organic solids mostly composed of H, C and N atoms. The term tholins designates solid products formed by organic chemistry in gas mixtures exposed to electrical discharges or ultraviolet radiation. 1,2 Since the pioneering experiments by Urey and Miller, 3 which were focused on the origin of life on Earth, numerous studies have been prompted by new fields of interest: formation of cometary refractory organics, 4,5 formation of Titan’s aerosols 6 and composition of reddish icy surfaces of satellites in the outer solar system. 7 The so-called Titan’s tholins are formed from N 2 –CH 4 gas mixtures, in the general framework of simulating the chemistry in Titan’s atmosphere. They have received a LPG, Laboratoire de Plan etologie de Grenoble, CNRS, Universit e J. Fourier, Grenoble, France b LISA, Laboratoire Interuniversitaire des Syst emes Atmosph eriques, CNRS, Universit e Paris Est Cr eteil, Universit e Paris Diderot, Cr eteil, France c LATMOS, Laboratoire Atmosph eres, Milieux, Observations Spatiales, CNRS, Universit e Versailles St-Quentin, Universit e P. et M. Curie, Verri eres le Buisson, France ART  C003758C PAPER 147/23 www.rsc.org/faraday_d | Faraday Discussions 1 5 10 15 20 25 30 35 40 45 50 55 This journal is ª The Royal Society of Chemistry 2010 Faraday Discuss., 2010, 147, 1–14 | 1