Analysis of polar organic compouds in size resolved aerosol by Py-GC-MS and derivatisation GC-MS András Hoffer Max Planck Institute for Chemistry Mainz In cooperation with András Gelencsér, Marianne Blazsó

Objectives Identification and quantitative determination of polar organic compounds in aerosol extracts by derivatisation GC-MS (Mainz) - from all filter samples (including backup) - from MOUDI samples for the most abundant compounds Method has been established but speciation to be supported by GC chemical ionisation MS and GC- HRMS on selected samples (Hungary) Direct structural characterisation of bulk organic aerosol by on-line derivatisation Py-GC-MS (Hungary) - qualitative but yields information on HULIS / polyacids as well - relative ratios of pyrolysis products may be used for source apportionment (see Blazsó et al. JAAP)

Derivatisation Py-GC-MS methodology - pyrolysis: flash, 400°C, 20s - derivatisation reagents: TMAH 10  l, TBAH, BSTFA - GC column: HP5MS 0.32 x 30 m 0.25  m - temperature program: 50°C 1 min - 10°C/min 300°C hold 5min - identification: Wiley 275 spectrum library - sample need: spot of 0.3 cm 2 Instrumentation: Pyroprobe 2000 GC Agilent 6890 / MS 5973 (EI) (quadrupole)

Py-GC-MS with TMAH

Identified compounds 43 (39) compounds tentatively identified Major compound classes: - Monocarboxylic including fatty acids -(C 6 -C 28 ) - most abundant n-C 16 - few unsaturated compounds (C 18:1 ) - Dicarboxylic acids -(butanedioic acid, pentanedioic acid, methyl-butanedioic acid, 2-butenedioic acid) - Aromatic compounds di-, tri- hydroxy benzene and benzoic acids and/or methoxybenzoic acids and derivatives (TBAH derivatisation required)

- Anhydrosugars/sugars (levoglucosan) - n-alkanes(C 23 -C 28 ) The relative amount of the aromatic compounds to the levoglucosan are higher ( ) in the burning period compare to the transition period Some aromatic compounds (coumaryl compound) are missing from the transition period sample burning p eriod transition period C/G=1.09 S/G=0.65S/G=0.9 grass and softwood origin hardwood burning

Py-GC-MS with BSTFA

- Similar compound classes were identified as in the TMAH-treated sample. - The identified aromatic compounds where the same as in previous mesurements made with water extraction. - The relative amount of the aromatic compounds is higher in the burning period ( ). Hydrolysis of high MW compounds  mostly methoxy guaiacyl syringyl units can be identified (compare to Graham et al.) several aromatic hydroxy compounds in aqueous extract Identified compounds Derivatisation with TBAH

Instrumentation: GC Fisons 8000 / MS Trio 1000 (EI, quadrupol) - GC column: SPB5 0.32mm x 30 m 0.25  m - temperature program: 50°C 1 min  10°C/min 300°C hold 5min - sample need: ~ 6cm2 Sample preparation - Extract in ACN (6cm 3, 1h) - Derivatised with PFBHA (O-(2,3,4,5,6-pentafluorobenzyl) hydroxy amine after drying with BSTFA GC-MS measurements

Ion fragments EI : m/z=73, 75 [Si(CH 3 ) 3 ] +, [OH=Si(CH 3 ) 2 ] ·+ relative intensity: (20-100%) m/z =117 [COOSi(CH 3 ) 3 ] ·+ monocarboxylic acids relative intensity: 61-97% (except aromatic carboxylic acids) and strong M-15 as well m/z= 147 [(CH 3 ) 2 Si=OSi(CH 3 ) 3 ] ·+ 2 active H-atoms relative intensity: ~100% m/z= 181 [C 6 F 6 CH 2 ] + carbonyl groups relative intensity % /Yu et al. 1998/

- Identification of individual compound is underway - The identified compounds will be confirmed by standards - Quantification will be performed in SIM with internal standard method - Identification of individual compounds: end of March - Quantitative analysis: end of August - Data evaluation and writing papers: September - Planned time schedule of the work