Laboratory Mass Spectrometry Facility

TNA 7 and JRA 15

Activity PI: R. Thissen (LPG, Grenoble, France)

List of laboratories:

- LPG (Grenoble, France)- LCBOB (Paris, France)- IOCB (Prague, Czech Republic)- AMPL (Trento, Italy)

2 / 11 Description of the proposed infrastructure activity

Bring to planetary sciences community expertise of physical chemists in mass spectrometry

Offer to planetary sciences community access to a Facility with top-grade mass spectrometers distributed in different laboratories in Europe

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Mass spectrometers with sophisticated characteristics

Very high resolution mass spectrometry (Fourier Transform MS with resol. 105)

Gas or liquid chromatography coupled with mass spectrometry (GC-MS, LC-MS)

Pyrolysis coupled with GC-MS (solid samples)

MS/MS analysis and D/H exchange (chemical structure of molecules)

Different sources for introduction of gas and liquid (soluble extract) samples

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Example: MS/MS study chemical structure analysis of tholins

MS/MS of CxHyNz+ fragment ions obtained from tholins(laboratory analogues of Titan aerosols)

Somogyi et al. JACS (2005)

-HCN

-CH2NH2-NH3

Collision induced dissociation of mass-selected ions

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Specific contribution to EuroPlaNet I3

Mass Spectrometry Facility =network of European top-grade MS instruments for Planetary Sciences

Bring together MS physical chemist expertise for• interpretation of space data on complex molecular

species• chemical sample analysis

Question:common integrated activity with Mass Spectrometers for solid sample analysis?(see B. Marty’s talk)

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TNA and JRA with budget

TNA (520 keuros)• Travel costs for external users• Mass Spectrometers operation costs (20% of

time operation for external users)• Postdoc positions

JRA (600 keuros)• Improvements of the mass spectrometer

sources (ex: development of a VUV continuum source)

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Important molecular synthesis,

even at 1200 km altitude

Mass spectrum up to 100

Mass resolution limited to 1

Modelisation is essential to identify CxHyNz+ ions

m/z 68

C5H8+ C3H4N2

+

Cassini mass spectrometer (INMS) First results (April 2005)

complex CxHyNz+ ions !

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Example: what are the CxHyNz+ ions observed by INMS on Cassini in Titan ionosphere?

CxHyNz+ can have the same nominal mass as C(x+1)H(y+2)N(z-1)+ as CH2 has the same mass as N

Ex: m/z 173 C11H13N2+ or C13H17

+

--> needs very high mass resolution

CxHyNz+ ions correspond to many possible isomers--> needs for structural/functional analysis

Reactions forming CxHyNz+ ions are not well known--> what is the growth chemical scheme and where

does it stop?

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New experimental set-up:

MS/MSHigh Resolution Mass spectrom

Reactions

11 / 11High mass resolution?

Example of cigarette smoke analysis

Resolution: 6000

Resolution: 12000

12 / 11 The « underestimated channels »active synthesis of neutral molecules

Vuitton et al. 2006

NH

3

CH

2N

H

CH

3C

N

C2H

3C

NC

2H

5C

N

Assuming that the missing peaks correspond to protonated, N-containing molecules,

ion densities allowTo propose a density for neutral molecules, totally Unexptected at such high altitudes and revealing a process of neutral syntheses in the ionosphere

18

30 42

56

54

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many reactions are missing

Result of the uncertainty propagationCarrasco et al, Planet. Space Sci. 2006, in press

Cassini INMS mass spectrum

Simulated mass spectrum

Ionospheric model of M. Banaszkiewicz et al. Icarus (2000) Uncertainties on rate constants and branching

ratios

Same simulated spectrum with 248 reactions instead of 584 !

1200 km

strongly underestimated

1418

30

HCNH+