Gas Chromatographic–Mass Spectrometric Analysis of Hydrocarbons and Other Neutral Organic Compounds in Volcanic Gases using SPME for Sample Preparation G. Mangani 1 / A. Berloni 1 / B. Capaccioni 2 / F. Tassi 3 / M. Maione 1 * 1 University of Urbino, Centre for the Study of Environmental Chemistry and for Advanced Instrumental Technologies, 6, Piazza Rinascimento, 61029 Urbino, Italy; E-Mail: michela@uniurb.it 2 University of Urbino, Institute of Volcanology and Geochemistry, Campus Scientifico Sogesta, 61029 Urbino, Italy 3 University of Florence, Department of Earth Sciences, 4 via La Pira, 50121 Florence, Italy Key Words Gas chromatography–mass spectrometry Solid-phase micro extraction Volcanic exhalation Neutral organic compounds Summary Knowledge of the chemical composition of volcanic exhalation is important in providing information on volcanic feeding systems and on the characteristics of the gaseous compounds emitted into the atmosphere. This paper reports a novel analytical method that makes use of capillary gas chromatography coupled to mass spectrometry, preceded by solid-phase micro extraction for sample enrichment. Such an approach enables considerable expansion of the number of neutral organic compounds that can be positively identified in volcanic exhalation. Data obtained from analysis of real samples are also reported. Introduction Volcanic processes are the most impres- sive manifestation of the earth’s internal energy. Among these, large explosive volcanic eruptions are certainly one of the most powerful natural phenomena, able to destroy very large areas in a few hours and to inject billions of tons of vitric ash into the atmosphere, suddenly modifying the climate all over the world for years or even decades. But volcanism has been also able to provide a much less impres- sive but no less important continuous input of chemicals to the earth’s surface since the primeval time of the earth. This process continues nowadays, its most evident manifestation being the typical gas exhalations usually associated with active or recently active volcanoes. In this way fundamental volatile inorganic spe- cies, primarily water but also carbon-, chlorine-, and sulphur-containing com- pounds, have been accumulating on the earth’s surface for billions of years, thus forming first the hydrosphere and then the biosphere. Current high-temperature (>300 °C) gas exhalations or ‘fumaroles’ still contain at least a fraction of ‘juvenile’ H 2 O and CO 2 as the main components and are typically associated with gaseous acid species such as SO 2 , HCl, and HF. Among the organic compounds present the occurrence of hydrocarbons heavier than methane, mostly alkenes and aro- matic compounds, has been documented for many different active volcanoes [1]. Low-temperature ‘hydrothermal’ gas exhalations, besides the main compo- nents CO 2 and H 2 S, also contain H 2 O, which is almost entirely ‘recycled’ from groundwater and seems to be character- ized by the absence of gaseous acidic species. In this gas alkanes and aromatic compounds are the prevailing hydrocar- bon species [2]. The recurrence of similar hydrocarbon patterns in similar gas exhalations on different volcanoes seems to suggest the effects of common pro- cesses of cracking and reforming driven by the prevailing physicochemical condi- tions on active volcanic systems and leading to a type of ‘inorganic’ produc- tion of new hydrocarbon molecules [3, 4]. The natural evolution of this research is to extend the investigations to other or- ganic compounds and to obtain further knowledge about the physicochemical condition of their feeding volcanic sys- tems, which can also provide new insights into the general problem of the origin of life [5]. Methodology developed for sampling and analysis of light (C 1 –C 6 ) hydrocar- bons from volcanic exhalations has been described elsewhere [3, 6]. Sampling and sample storage make use of a pre-evacu- ated 60-mL glass container containing a 6 M solution of NaOH. In this way all water-soluble gaseous species present in the volcanic emission are dissolved in the alkaline solution while other species, including light hydrocarbons, are en- riched in the evacuated part of the con- tainer. Then, using a rotary pump and a six-port valve connected to al 0.5-mL 10 3 3 7 0 1 3 1 Journal number Manuscript number B Dispatch: 11.11.2003 Journal : Chromatographia C568 No. of pages: 5 Author’s disk received 4 Used 4 Corrupted Mismatch Keyed DOI: 10.1365/s10337-003-0131-6 2003, 58, 1–5 0009-5893/03/jj $03.00/0 Ó 2003 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH Original Chromatographia 2003, 58, July (No. 1/2) 1