Oliver Botta

NASA Goddard Space Flight Center, Greenbelt, MD 20771

&

Goddard Earth Science and Technology Center, University of Maryland, Baltimore County

Baltimore, MD 21228

GODDARD ASTROBIOLOGY CENTER TEAM MEETING

March 23-24, 2006

Analysis of Organic Compounds in Terrestrial and Extraterrestrial Samples

NASA Astrobiology InstituteGoddard Center for Astrobiology

Background

• Organics in meteorites provide record of early solar system chemical processes

• Exogenous delivery of organic compounds

• Over 80 amino acids identified in the CM carbonaceous meteorite Murchison

• CM meteorites discovered in Antarctica have also been analyzed for amino acids

(Cronin and Moore, 1971; Kotra et al. 1979; Shimoyama et al.

1979; Shimoyama et al. 1985; Botta and Bada, 2002)

• Amino acid chemistry used to trace the nature of meteorite parent bodies (Ehrenfreund et al. 2001)

(Photo: ANSMET 2003/04)

Equipment at GSFC (1)

GC-QMS

GC-ToFMS

Equipment at GSFC (2)

LC-UVF-ToFMS

Peak X

-amino-n-caproic acid (EACA)

+ H2OH-[NH(CH2)5CO]n-OH

Nylon-6

COOHNH2

AIB

Antarctic Ice Analysis

• First ice samples from a meteorite stranding surface, directly underneath a meteorite

• Ice was processed by melting, evaporation and filtration.

• PAH analysis of meteorite samples and ice extracts with L2MS (ETH Zurich, R. Zenobi)

• Amino acid analysis of the ice samples with LC-UVF-ToFMS at GSFC.

• Amino acid analysis of the meteorite samples are ongoing.

AIB in Antarctic Ice

Amino Acid16186

(LAP 03784)16167

(LAP 03573)167045

(LAP 03624)16154

(LAP 03637)16031

(LAP 03553)Non-associated

Ice Sample

D-Aspartic Acid < 1.251 < 0.20 < 0.46 < 1.32 < 0.97 < 0.78

L-Aspartic Acid < 1.44 < 1.70 < 1.23 < 0.88 < 1.05 < 0.78

L-Glutamic Acid < 1.76 < 2.12 < 0.02 < 4.88 < 1.11 < 1.08

D-Glutamic Acid < 0.17 < 0.47 < 0.02 < 1.05 < 1.45 < 0.67

D-Serine < 0.47 < 0.11 < 0.02 < 0.45 < 0.35 < 0.40

L-Serine 1.64 ±1.14 <7.98 <0.02 <2.70 <1.14 <2.73

Glycine 8.89±2.04 <18.72 <3.92 4.87±2.33 <7.50 7.24±4.81

β-Alanine <0.74 <0.75 <0.12 0.49±0.57 <0.27 <0.60

γ-ABA 1.05±0.34 1.43±0.14 <0.03 <0.61 <0.66 0.23±0.21

D-Alanine 2.34±0.82 3.96±0.61 <0.14 0.12±1.09 <1.08 1.48±1.60

L-Alanine 4.35±0.78 <8.29 <0.59 2.03±0.95 <0.60 <4.11

α-&β-AIB4 14.28±6.662

27.86±2.563

4.29±0.982

1.45±0.323

11.78±3.012

11.713

<0.18 <0.15 20.06±4.512

33.13±10.63

α-ABA <0.09 <0.007 <0.03 <0.0005 <0.07 <0.003

D-Isovaline <0.50 <0.39 <0.04 <0.23 <0.23 <0.28

L-Isovaline <1.19 <6.86 <0.05 <0.63 <0.61 <0.50

L-Valine <2.47 <6.06 <0.04 <0.64 <0.09 1.50±1.82

D-Valine <0.12 <0.12 <0.05 <0.004 <0.09 <0.10

1 Concentrations reported with “<” were very similar to blank levels and are considered to be maximum values.2 From fluorescence data.3 From mass data.4 These isomers could not be separated under the separation conditions applied.5 The concentration data for this sample I based on three measurements.Abbreviations: ABA: Amino-n-butyric acid, AIB: Aminoisobutyric acid.

• Three possible explanations for depletion :

1) Leaching of water-extractable amino acids during residence time in Antarctic ice (several ka, Jull et al. 1998)

2) Extensive aqueous alteration on meteorite parent body (Zolensky and Browning, 1994)

3) CM1 meteorites originated on parent body that was chemically distinct from the other CM2 meteorites

• CM1 carbonaceous chondrites contain significantly lower abundances of amino acids compared to the CM2s Murchison and LEW 90500 (generally by a factor 2 - 3).

CM1 Amino Acid Composition

CM1 Amino Acid Composition

Data for Orgueil and Ivuna meteorites taken from Ehrenfreund et al. 2001.

Rel

ativ

e m

ola

r ab

un

dan

ce

(gly

cin

e =

1)

0

0.5

1

1.5

2

2.5

b-Ala

g-ABA

D-Ala

AIB

Murchison(CM2)

LEW90500(CM2)

ALH88045(CM1)

MET01070(CM1)

LAP02277(CM1)

Orgueil(CI)

Ivuna(CI)

• Three possible explanations for depletion :

1) Leaching of water-extractable amino acids during residence time in Antarctic ice (several ka, Jull et al. 1998)

2) Extensive aqueous alteration on meteorite parent body (Zolensky and Browning, 1994)

3) CM1 meteorites originated on parent body that was chemically distinct from the other CM2 meteorites

• CM1 carbonaceous chondrites contain significantly lower abundances of amino acids compared to the CM2s Murchison and LEW 90500 (generally by a factor 2 - 3).

CM1 Amino Acid Composition

• Relative amino acid abundances suggest that the third possibility is the most likely one, although influences by the other two processes can not be excluded.

Nucleobases in Murchison

… with Zita Martins, Pascale Ehrenfreund (Leiden)Mark Sephton (Imperial College)Marilyn Fogel (CIW)

N

NHN

NH

NH2

NH

NHN

NH

O

ON

NHN

NH

O

NH2 N

NHN

NH

O

ADENINE GUANINE HYPOXANTHINE XANTHINE

NH

NH

O

O

URACIL

• Nucleobases detected in Murchison at 300 to 500 ppb level

(Schwartz and coworkers, 1979-1981).

• Extraterrestrial origin of these compounds was inferred.

• Stable isotope measurements.

• BSTFA and MTBSTFA

Conclusions

• LC-ToF-MS coupled with UV fluorescence is a powerful tool for the identification of amino acids in meteorites.

• High concentration of EACA (likely derived from Nylon meteorite storage bag) has implications for future collection procedures of meteorites in Antarctica.

• Detection of AIB in Antarctic ice was unexpected. More ice samples from other stranding surfaces and search for AMMs in these samples are needed for future experiments.

• CM1 carbonaceous chondrites show a unique amino acid distribution that suggests that they originated on chemically distinct parent body.

• Nucleobases in the Murchison meteorite …..

Acknowledgments

Thanks to K. Righter, T. McCoy, and L. Welzenbach for providing the meteorite samples used in this study.

Thanks to everybody here at Goddard for support in these experiments.

SAM Prototype System

Protocol

Meteorite powder (~100 mg)

Water extraction (100ºC 24 h)

Acid hydrolysis (6 M HCl 150ºC 3 h)

Desalting (AG50W-X8 resin)

Derivatization (OPA/NAC primary amines)

HPLC with UV fluorescence

+ ToF-MS detection

Amino Acid Identification

Simultaneous UV fluorescence and ToF-MS detection

OPA/NAC-glycineMW = 336.1