3rd PaleoSalt Meeting, Angers, June 2008 WP2: Mass Spectrometric Analysis of the Elemental and Molecular Composition of Calcite Samples and an Alkenone Mixture 3 rd PaleoSalt Meeting, Angers

3rd PaleoSalt Meeting, Angers, June 2008 Progress in Experimental Setup 1)electron impact gun (Ar + ) (for cleaning and ablation) 2)liquid metal ion gun (Ga + ) (for primary ion bombardment) 3)sample holder 4)extraction optics 5)time-of-flight MS with reflectron 6)ion detector 7)laser system exciplex laser non-resonant excitation (running) fs-laser non-resonant excitation (running / software) tuneable dye-laser Nd:YAG- laser resonant excitation (running) dye laser system new 

3rd PaleoSalt Meeting, Angers, June 2008 Samples Coral core Mixture of alkenones Foraminiferal Shells [provided by Paula Diz (BIAF)] -collected form environments with different salinities -aim: identification of metal/Ca ratios that correspond to the salinity variation -method: non-resonant laser-SNMS -first measurements: reduction of signal from residual gas necessary  reduction of ionisation volume (aperture) and additional vacuum pump (TSP) -difficult handling / preparation due to size and charging (suggestions?) Embedded foraminiferal shells [provided by Gernot Nehrke (AWI)] -cross section in polished resin block -Mg banding in the shell wall -aim: correlation between Mg and organic compounds -method: SIMS and non-resonant laser-SNMS -first results: SIMS signal too small  next step: laser-SNMS Rhinoceros Tooth [provided Martha Koot (NIOZ)] -aim: oxygen isotope measurement -method: SIMS

3rd PaleoSalt Meeting, Angers, June 2008 Coral Core - background Sample: 7 mm slab of a coral core [provided by Craig Grove (NIOZ)] Question: Does the lateral variation of the Barium concentration correspond to the UV- luminescent lines? Preparation: no cleaning or pre-bombardment Method: -SIMS (primary ions: Bi + / positive secondary ions analysed) -macro scan image (→ sample moved under primary ion beam) Problem: porosity of the sample  typically leads to: reduced mass resolution and stronger back ground signal due to topographic effects

3rd PaleoSalt Meeting, Angers, June 2008 Coral Core - images intensity : scale: low high Ca Ba both signals correspond at least mainly to structure of the sample (due to surface sensitivity) vertical banding in the Ba image expected (spacing: 1 – 2 cm) apparently no variation in the Ba signal  reduction of the influence of the porosity necessary  line scan in x direction (with integration in y direction) x y analysed area: 20 mm x 2,5 mm

3rd PaleoSalt Meeting, Angers, June 2008 Coral Core – line scan Ca

3rd PaleoSalt Meeting, Angers, June 2008 Coral Core – line scan Ca

3rd PaleoSalt Meeting, Angers, June 2008 Coral Core - summary intensity : scale: low high Ca Ba lateral variation in Ba concentration can be seen (despite the porosity) next steps: -measurements on other part of the sample to verify the results -non-resonant Laser-SNMS (stronger Ba signal?) -matching the lateral variations in the Ba concentration with luminescent lines (new sample with stronger UV luminescence necessary) x y analysed area: 20 mm x 2,5 mm

3rd PaleoSalt Meeting, Angers, June 2008 Alkenones - background Sample: mixture of purified alkenones from Emiliania huxleyi [provided by Marcel van der Meer (NIOZ)] Question: -Is it possible to distinguish between alkenones with different chain lengths (37 – 39 C atoms) with SIMS? Preparation: -0,19 mg solved in 200 µl n-Hexane -30 µl pipetted on cleaned Si-wafer -no pre-bombardment Method: -SIMS (primary ions: Bi 3 +  polyatomic bombardment  molecular emission enhanced) -spectra (positive and negative secondary ions analysed)

3rd PaleoSalt Meeting, Angers, June 2008 Alkenones - GC spectrum C37:3 C37:2 C38 C39 original molecules: C n H 2(n-x) O (e.g. C 37 H 70 O = C 37:2 ) (with n = number of C atoms, x = number of double bonds) provided by: Marcel van der Meer (NIOZ):

3rd PaleoSalt Meeting, Angers, June 2008 Alkenones – positive SIMS spectrum C 37 H 65 O C 37 H 67 O C 37 H 69 O C 38 H 67 O C 38 H 69 O C 38 H 71 O C 39 H 69 O C 39 H 71 O C 39 H 73 O C 37:2 C 37:3 original molecules can be found (minus one H atom) peak patterns due to intramolecular rearrangement during sputtering process additional signals C 38 C 39

3rd PaleoSalt Meeting, Angers, June 2008 Alkenones – negative SIMS spectrum C 37 H 65 O C 37 H 67 O C 37 H 69 O C 38 H 67 O C 38 H 69 O C 38 H 71 O C 39 H 69 O C 39 H 71 O C 39 H 73 O C 37:2 C 37:3 C 38 C 39 higher signal without additional signal shift in relative peak height interesting for fs-laser-SNMS