International Journal of Astrobiology

Table of Contents - July 2011 - Volume 10, Special Issue 03 (Special issue: Astrobiology field research in Moon/Mars analogue environments)  

Research Article

Analysis of Mars analogue soil samples using solid-phase microextraction, organic solvent extraction and gas chromatography/mass spectrometry

G. E. Orzechowskaa1, R. D. Kidda1 c1, B. H. Foinga2, I. Kanika1, C. Stokera3 and P. Ehrenfreunda4a5

a1 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA

a2 European Space Agency (ESA), ESTEC SRE-S, Postbus 299, 2200AG Noordwijk, The Netherlands

a3 NASA Ames Research Center, Moffett Field, CA 94035, USA

a4 Space Policy Institute, George Washington University, Washington 20052, USA

a5 Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are robust and abundant molecules in extraterrestrial environments. They are found ubiquitously in the interstellar medium and have been identified in extracts of meteorites collected on Earth. PAHs are important target molecules for planetary exploration missions that investigate the organic inventory of planets, moons and small bodies. This study is part of an interdisciplinary preparation phase to search for organic molecules and life on Mars. We have investigated PAH compounds in desert soils to determine their composition, distribution and stability. Soil samples (Mars analogue soils) were collected at desert areas of Utah in the vicinity of the Mars Desert Research Station (MDRS), in the Arequipa region in Peru and from the Jutland region of Denmark. The aim of this study was to optimize the solid-phase microextraction (SPME) method for fast screening and determination of PAHs in soil samples. This method minimizes sample handling and preserves the chemical integrity of the sample. Complementary liquid extraction was used to obtain information on five- and six-ring PAH compounds. The measured concentrations of PAHs are, in general, very low, ranging from 1 to 60 ng g−1. The texture of soils is mostly sandy loam with few samples being 100 % silt. Collected soils are moderately basic with pH values of 8–9 except for the Salten Skov soil, which is slightly acidic. Although the diverse and variable microbial populations of the samples at the sample sites might have affected the levels and variety of PAHs detected, SPME appears to be a rapid, viable field sampling technique with implications for use on planetary missions.

(Received November 30 2010)

(Accepted December 10 2010)

(Online publication January 20 2011)

Key words

Correspondence:

c1 e-mail: Richard.D.Kidd@jpl.nasa.gov