1. Determination of carbonyl compounds from monoterpene oxidation using the IfT chamber Ariane Kahnt 23.06.2008 Leibniz-Institut für Troposphärenforschung Permoserstr. 15 04318 Leipzig, Germany

2. 2/38 Content 1. Introduction 2. Experimental 3. Method development for carbonyl compound analysis 4. In-situ derivatisation of carbonyl compounds on DNPH- coated denuders 5. First results from gas- and particle-phase analysis 6. Further improvement 7. Summary

3. 3/38 Introduction - Monoterpenes are biogenic volatile organic compounds (BVOC) - Emission from various plants and coniferyl trees

4. 4/38 Introduction - Estimated global emission of volatile organic compounds (VOC): 1150 Tg C/year (Guenther et al. 1995): comprised of - 44 % isoprene - 11 % monoterpenes - BVOC emission exceed those of anthropogenic compounds by a factor of ~10. - Most BVOCs are more reactive than many anthropogenic non-methane volatile organic compounds (NMVOC)

5. 5/38 Introduction Monoterpenes - C 10 H 16 -skeleton  -pinene  -pinene limonene 3-carene camphene sabinene - Act as repellent, Pheromone for insects - Most abundant monoterpenes emitted are  -pinene,  -pinene and limonene

6. 6/38 Introduction - Atmospheric degradation of monoterpenes includes reactions with NO 3, OH radicals and O 3 - Oxidation leads to multifunctional oxidation products with low vapour pressure - Their condensation and coagulation-processes lead to particle formation / growth (formation of secondary organic aerosol = SOA) - SOA scatters solar radiation and can act as cloud condensation nuclei

7. 7/38 Introduction Challenge: -SOA formation is complex and not well known -Composition of SOA is largely unknown Motivation: -Emission of BVOC is driven by climate (temperature, light) -Atmospheric oxidation leads to products that effect climate -Get more information about the oxidative decomposition of monoterpenes

8. 8/38 Introduction -Monoterpene oxidation produces semivolatiles and (or) multifunctional compounds such as carbonyl compounds and caboxylic acids -Carbonyls play an important role in photochemical reactions -Carbonyl compounds undergo photolysis and react with OH and NO 3 radicals -Some of them partition between the gas- and particle-phases

9. 9/38 Introduction Mainly first oxidation products from monoterpenes are oxo-compounds (aldheydes and ketones) Their reactions are not well characterised -What are the next oxidation products? -What are their yields? -What are the mechanisms? The challenge is: -Carbonyl compounds are hard to sample and analyse -Not all reaction products are available for positive identification and quantification

10. 10/38 Introduction Examples of aldehydes originating from monoterpenes Campholenic aldehyde Endolim (from limonene) Nopinon (from β-pinene) Pinonaldehyde (from  -pinene)

11. 11/38 Experimental

12. 12/38 Experimental Aerosol chamber at the IfT (LEAK – „Leipziger Aerosol Kammer“) -Overall chemistry in the atmosphere is far complex -Chamber studies provide a better understanding of atmospheric reactions -Controlled parameters LEAK („Leipziger Aerosol Kammer“ at the IfT)

13. 13/38 Experimental Characteristics of the IfT chamber -Made of Teflon ® foil -Cylindrical geometry -Volume: 19 m 3 -Surface/volume ratio: 2.1 m -1 -60 UV-lamps -Thermostat

14. 14/38 Experimental Analysis of carbonyl compounds -Polar carbonyl group -Some carbonyls can partially or completely pass the sampling or analytical technique -Derivatisation is necessary: e.g. with 2,4-Dinitrophenylhydrazine (DNPH)

15. 15/38 Experimental -DNPH is a derivatisation reagent for aldehyde- and keto-groups -Precipitation reagent -Well known method for the identification of aldehydes and ketons by the melting points of the formed hydrazones (Brady 1931; Allen 1937) -The formed hydrazones are: -Coloured. This makes them detectable with UV-spectroscopy -Easily ionisable using electrospray ionisation (ESI). This makes them detectable with HPLC/ESI-MS. solution of DNPH addition of a carbonyl compound

16. 16/38 Experimental Analysis of the hydrazones: HPLC-UV coupled with ESI-TOFMS HPLC (high performance liquid chromatography): -Separation of compounds based on their distribution between a stationary phase (column) and a mobile phase (eluent) -Depending on their affinity to the phases. The compounds are eluted at certain time ESI-TOFMS (Electrospray Ionisation Time-Of-Flight Mass Spectrometry) -Ionisation of the compounds by electrospray -Formed ions are accelerated in an electric field -The velocity of ions depends on mass to charge ratios (m/z); hence the mass to charge ratios of the analyte ions can be calculated from the time required for the ions to reach a detector -TOF-MS is a high resolution mass spectrometer

17. 17/38 Experimental First Step Method development for standard compounds -Available or synthesised monoterpene oxidation products were derivatised: -Campholenic aldehyde -Endolim -Nopinone -Pinonaldehyde to form the respective hydrazone -Analysis and characterisation with HPLC/ESI-TOFMS

18. 18/38 Results from the method development of carbonyl compound analysis

19. 19/38 Method development for carbonyl analysis Hydrazone standardStructureM [g/mol] Benzaldehyde-DNPH C 13 H 10 N 4 O 4 286 Campholenic aldehyde- DNPH C 16 H 20 N 4 O 4 332 Endolim-di-DNPH C 22 H 24 N 8 O 8 528

20. 20/38 Method development for carbonyl analysis Hydrazone standardStructureM [g/mol] Nopinon-DNPH C 15 H 18 N 4 O 4 318 Pinonaldehyde-di- DNPH C 22 H 24 N 8 O 8 528

21. 21/38 Method development for carbonyl analysis Standard-Hydrazone-Mix Benzaldehyde (m/z 285), Pinonaldehyde (m/z 527) Nopinon (m/z 317), Campholenic aldehyde (m/z 331), Endolim (m/z 527)

22. 22/38 Method development for carbonyl analysis Characterisation of the analytical method Hydrazone standard RT [min] R2R2 LOD [  g/ml] RSD [%] Benzaldehyde 11.40.99790.0122.49 Campholenic aldehyde 14.20.99700.0243.56 Endolim 15.10.99560.0979.53 Nopinon 13.50.99930.0722.87 Pinonaldehyde 15.10.99430.0058.71

23. 23/38 Method development for carbonyl analysis Suitable method regarding: - chromatographic separation (except the isobaric hydrazones of endolim and pinonaldehyde) - sensitivity - stability TOFMS allows the determination of exact chemical formula also for unknown compounds due to its high sensitivity

24. 24/38 Method development for carbonyl analysis -To collect also small carbonyl compounds which can not be collected with resin based denuder-sampling, on-tube derivatisation is performed Use of annular denuders: Advantages: - Larger sampling capacity - Operate at higher sample flow rates Disadvantage: - Diffusion equation not characterised

25. 25/38 Method development for carbonyl analysis Coated Denuders -With the adsorbent XAD-4 as a collection surface -Additional with DNPH + H 3 PO 4 for the on-tube conversion of carbonyl compounds

26. 26/38 In-situ derivatisation of carbonyl compounds on DNPH-coated denuders

27. 27/38 In-situ derivatisation of carbonyl compounds on DNPH-coated denuders - First compound: campholenic aldehyde - Chamber experiments with different concentration of campholenic aldehyde - Sampling with the DNPH-coated denuder - Denuder extraction - Analysis with the developed HPLC/ESI-TOFMS method injected concentration [ppb] 10 40 80 160

28. 28/38 In-situ derivatisation of carbonyl compounds on DNPH-coated denuders Gas-phase calibration of campholenic aldehyde on DNPH-coated denuders

29. 29/38 - Cleaning procedure is necessary to remove the acid - Should be done directly after the experiment SPE (solid phase extraction) Oasis ® HLB cartridges with a Hydrophilic-Lipophilic-Balanced sorbent - Reversed phase polymer sorbent

30. 30/38 First results from gas- and particle- phase analysis

31. 31/38 Results from gas- and particle-phase analysis Chamber experiment  -pinene Initial HC concentration [ppb] 100 O3O3 60 RH [%] ~ 50 T [°C]21±1 Reaction time [h]2.5 Sampling time [h]1 Seed particleNH 4 HSO 4

32. 32/38 Results from gas- and particle-phase analysis Filter Extract: particle-phase products - Identification of the hydrazones from formaldehyde (m/z 209) and pinonaldehyde (m/z 527)

33. 33/38 Results from gas- and particle-phase analysis Denuder Extract: gas-phase products - Identification of the hydrazones from formaldehyde (m/z 209), acetone (m/z 237) and pinonaldehyd (m/z 527)

34. 34/38 Results from gas- and particle-phase analysis Preliminary quantitative result Yield by massReferences Pinonaldehyde Gas-phase: 0.24 Particle-phase: 0.01 0.51±0.06 Hatakeyama et al. (1989) 0.19±0.04 Hakola et al. (1994) 0.06±0.19 Yu et al. (1999) 0.164±0.029 Baker et al. (2002)

35. 35/38 Further improvement Further characterisation of in-situ derivatisation on denuders has to be done to improve quantification: -Denuder properties (e.g. variation between duty cycle, variability between different denuders) -SPE method (recovery) -More standards need to be prepared (HCHO, acetone etc...)

36. 36/38 Summary - An HPLC-ESI-TOFMS method was developed for some first generation monoterpene oxidation products (endolim, nopinon, pinonaldehyde) - In-situ derivatistion on DNPH-coated denuders with campholenic aldehyde was performed and show a very good collection efficiency - From the ozonolysis experiment of  -pinene several carbonyl compounds were identified. The yield of pinonaldehyde in the gas- and particle-phase was determined

37. 37/38 Acknowledgements - Organiser of the summer school - EUCAARI (European Commission grant number 036833) - IfT chamber team

38. 38/38 End Thank You very much for your attention!

39. 39/38 Derivatisation with 2.4-Dinitrophenylhydrazine - Gives coloured hydrazones (UV detection possible!) - Detection at the wavelength near the absorption maxima of the respective hydrazone (360 nm)

40. 40/38 Oasis ® HLB cartridges - Contain a reversed phase sorbent (Hydrophilic-Lipophilic-Balanced) - Copolymer with aligned ratio of hydrophilic (N-Vinylpyrrolidone) and lipophilic compound (Divinylbenzene) - Robust (pH) General procedure: - Coloumn solvation with methanol. water. acetonitrile - Coloumn conditioning with the sample medium - Sample loading - Coloumn washing with water - Target compound elution with acetonitrile

41. 41/38 Conditions for HPLC-UV-ESI-TOFMS analysis Column Phenomenex ® Gemini C 6 Phenyl (3.5 µm. 150 x 2 mm) Eluents 0.2 % acetic acid in water (A) and 0.2 % acetic acid in acetonitrile (B) (programme: 70% A to 10% in 15 min) Flow rate 0.5 ml/min Sample injection 10 µl Mass calibration 0.2 % acetic acid/5 mM NaOH in 50/50 (v/v %) in water/i-propanol solution at the beginning of analysis