Formaldeído: este veneno pode ter iniciado o cenário para as origens da vida

Formaldehyde: Poison Could Have Set the Stage for the Origins of Life

ScienceDaily (Apr. 4, 2011) — Formaldehyde, a poison and a common molecule throughout the universe, is likely the source of the solar system's organic carbon solids -- abundant in both comets and asteroids. Scientists have long speculated about the how organic, or carbon-containing, material became a part of the solar system's fabric. New research from Carnegie's George Cody, along with Conel Alexander and Larry Nittler, shows that these complex organic solids were likely made from formaldehyde in the primitive solar system.

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Their work is published online April 4 by the Proceedings of the National Academy of Sciences.

"We may owe our existence on this planet to interstellar formaldehyde," Cody said. "And what's ironic about it is that formaldehyde is poisonous to life on Earth."

During the early period of the inner solar system's formation, much of the organic carbon that wasn't trapped in primitive bodies was lost to space, along with much of the water. Prior to this study numerous competing ideas emerged to explain the existence of primitive organic solids. Cody, of the Geophysical Laboratory, along with Alexander and Nittler, of the Department of Terrestrial Magnetism, and the team decided to study primitive solar system objects using advanced methods. What they discovered clearly pointed to a polymer formed from formaldehyde.

They tested their conclusion with experiments to reproduce the type of organic matter found in carbonaceous chondrites, a type of organic-rich meteorite, starting with formaldehyde. They found that their formaldehyde-synthesized organic material was not only similar to that found in carbonaceous chondrites, but also similar to organic material found in a comet named 81P/Wild 2, pieces of which were collected in space by NASA's Stardust mission, as well as in interplanetary dust particles, or particles from space that likely originated from comets and asteroids.

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Establishing a molecular relationship between chondritic and cometary organic solids

1. George D. Cody^a,¹, 
2. Emily Heying^a, 
3. Conel M. O. Alexander^b,
4. Larry R. Nittler^b, 
5. A. L. David Kilcoyne^c, 
6. Scott A. Sandford^d, and 
7. Rhonda M. Stroud^e

+Author Affiliations

1. ^aGeophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015;
2. ^bDepartment of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015;
3. ^cAdvanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA 94720;
4. ^dAstrophyiscs Branch, Mail Stop 245-6, National Aeronautics and Space Administration Ames Research Center, Moffet Field, CA 94035; and
5. ^eNaval Research Laboratory, Washington, DC 20015

1. Edited* by Mark H. Thiemens, University of California, La Jolla, CA, and approved February 25, 2011 (received for review October 25, 2010)

Abstract

Multidimensional solid-state NMR spectroscopy is used to refine the identification and abundance determination of functional groups in insoluble organic matter (IOM) isolated from a carbonaceous chondrite (Murchison, CM2). It is shown that IOM is composed primarily of highly substituted single ring aromatics, substituted furan/pyran moieties, highly branched oxygenated aliphatics, and carbonyl groups. A pathway for producing an IOM-like molecular structure through formaldehyde polymerization is proposed and tested experimentally. Solid-state ¹³C NMR analysis of aqueously altered formaldehyde polymer reveals considerable similarity with chondritic IOM. Carbon X-ray absorption near edge structure spectroscopy of formaldehyde polymer reveals the presence of similar functional groups across certain Comet 81P/Wild 2 organic solids, interplanetary dust particles, and primitive IOM. Variation in functional group concentration amongst these extraterrestrial materials is understood to be a result of various degrees of processing in the parent bodies, in space, during atmospheric entry, etc. These results support the hypothesis that chondritic IOM and cometary refractory organic solids are related chemically and likely were derived from formaldehyde polymer. The fine-scale morphology of formaldehyde polymer produced in the experiment reveals abundant nanospherules that are similar in size and shape to organic nanoglobules that are ubiquitous in primitive chondrites.

Footnotes

• ↵¹To whom correspondence should be addressed. E-mail: gcody@ciw.edu.

• Author contributions: G.D.C. designed research; G.D.C., E.H., C.M.A., L.R.N., A.L.D.K., and R.M.S. performed research; G.D.C., C.M.A., L.R.N., A.L.D.K., S.A.S., and R.M.S. analyzed data; and G.D.C. wrote the paper.
• The authors declare no conflict of interest.
• *This Direct Submission article had a prearranged editor.
• This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1015913108/-/DCSupplemental.

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