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 2 H = ( 2 H / 1 H) Sample vs. ( 2 H / 1 H) Reference 13 C/ 12 C – 15 N/ 14 N – 18 O/ 16 O – 34 S/ 32 S – 37 Cl/ 35 Cl – 81 Br/ 79 Br.

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Presentation on theme: " 2 H = ( 2 H / 1 H) Sample vs. ( 2 H / 1 H) Reference 13 C/ 12 C – 15 N/ 14 N – 18 O/ 16 O – 34 S/ 32 S – 37 Cl/ 35 Cl – 81 Br/ 79 Br."— Presentation transcript:

1  2 H = ( 2 H / 1 H) Sample vs. ( 2 H / 1 H) Reference 13 C/ 12 C – 15 N/ 14 N – 18 O/ 16 O – 34 S/ 32 S – 37 Cl/ 35 Cl – 81 Br/ 79 Br

2 Malin Söderman Junior Research Engineer

3 We develop methods – Visitors come and use them Self-cost model We are available for -General isotope advice (planning) - Collaboration - One-off - Short term - Long term - Proposal assist

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5 … Equilibrium Isotope Effects (EIE) – isotopic phase partitioning … Kinetic Isotope Effects (KIE) – isotopic reaction rates Zero-point energies…  =(1/2+n)h    (  /m) ½ Vibrational frequency Isotope mass Force constant

6 Heavy isotopes favour a strong bond The Equilibrium Isotope Effect ( 2 H / 1 H) Phase X-H* ( 2 H / 1 H) Phase Y-H* EIE = solventanalyte

7 The Kinetic Isotope Effect k rate =Ae -Ea/RT Free energy Reaction coordinate E a Light E E a Heavy E KIE = k Light / k Heavy

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10 …KIE = k Light / k Heavy Holmstrand et al., Chemosphere 69 (2007) 1533–1539 DDT DDE

11 KIEs of 3 photochemical reactions  13 C  15 N 2H2H Hartenbach et al, Environ. Sci. Technol. 2008, 42, 7751–7756 Isotope composition Atrazine Concentration

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13 R(+) or S(-) Catalysis by DL-2-haloacid dehalogenase for stereo isomers as determined from Kinetic Isotope Effects (KIEs) Papajak et al., Biochemistry 2006, 45,

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15 An Equilibrium Isotope Effect Molecular oxygen adducts in metalloenzymes – side-on or end-on? Side-on End-on

16 The characterization of intermediates in oxidation reactions of transition metals – Metalloenzymes Side-on End-on The derived oxygen isotopic effects have been used to (i) differentiate inner-sphere from outer-sphere electron transfer (ii) identify metal-O2 intermediates (iii) assess mechanisms of O-O bond-breaking/making reactions Ashley, Brinkley and Roth, Oxygen Isotope Effects as Structural and Mechanistic Probes in Inorganic Oxidation Chemistry, Inorg. Chem. 2010, 49, 3661–3675

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18 “No deuterium was incorporated… the active site of the enzyme is probably in a closed conformation during catalysis” Hydrogen exchange labeling to study a reaction mechnism - choice of labels and analytical technique 2 H label Natural 2 H level Guangqi et al., Biochimie 92 (2010) 1454e1457 Tracers and labels: - Is natural abundance enough? (safety, cost, feasibility) - Can KIE or EIE help? (additional information) - Added value of IRMS instruments? (trace weaker signals)

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20 Macronutrient sourcing for biosynthesis using  13 C analysis of amino acids – direct routing from diet to tissue Filled = dietOpen = collagen Diet composition DietProteinEnergy D2AC3C3 C3C3 D3GC3C3 C4C4 D4HC4C4 C4C4 D5IC4C4 C3C3 Jim et al., British Journal of Nutrition (2006), 95, 1055–1062 C3C3 C4C4 -25‰ -12‰ C 3 plants = - 25‰ (e.g. rice) C 4 plants = - 12‰ (maize)

21 ? ? Chemistry Labeling Reaction mechanisms Reaction monitoring Reaction identification Linking source & product Environmental sciences Ecology Plant physiology Microbiology Biochemistry

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23 Cell phone: Website:http://delta.geo.su.se …where you will find this presentation…


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