analysis of polar o rganic compouds in size resolved aerosol by py gc ms and derivatisation gc ms
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Analysis of polar o rganic compouds in size resolved aerosol by Py-GC-MS and derivatisation GC-MS. A ndrás Hoffer Max Planck Institute for Chemistry Mainz In cooperation with András Gelencsér, Marianne Blaz só. Objectives.

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analysis of polar o rganic compouds in size resolved aerosol by py gc ms and derivatisation gc ms

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
Objectives
  • Identification and quantitative determination of polar organiccompounds 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
Derivatisation Py-GC-MS methodology

Instrumentation: Pyroprobe 2000

GC Agilent 6890 / MS 5973 (EI) (quadrupole)

  • 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 cm2
p y gc ms with tmah

Abundance

1400000

HV19 (burning period)

1200000

1000000

800000

600000

400000

200000

0

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Time-->

Abundance

HV71 (transition period)

1400000

1200000

1000000

800000

600000

400000

200000

0

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Time-->

Py-GC-MS with TMAH
identified c ompounds

43 (39) compoundstentatively identified

  • Major compound classes:
  • Monocarboxylic including fatty acids
    • (C6-C28)
    • most abundant n-C16
    • few unsaturated compounds (C18:1)
  • 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)
Identified compounds
slide6

- Anhydrosugars/sugars(levoglucosan)

  • n-alkanes (C23-C28)
  • The relative amount of the aromatic compounds to the levoglucosan are
  • higher (1.3 - 5) 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=0.65 S/G=0.9
  • grass and softwood origin hardwood burning
py gc ms with bstfa

Abundance

4.5e+07

HV19 (burning period)

3.5e+07

2.5e+07

1.5e+07

5000000

0

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

24.00

26.00

28.00

Time-->

Abundance

2e+07

HV71 transition period

1.6e+07

1.2e+07

8000000

4000000

0

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

24.00

26.00

28.00

Time-->

Py-GC-MS with BSTFA
identified compounds

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 (1.4-5.5).

Identified compounds

Derivatisation with TBAH

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

gc ms measurements
GC-MS measurements

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 (6cm3, 1h)
    • Derivatised with PFBHA (O-(2,3,4,5,6-pentafluorobenzyl) hydroxy amine
  • after drying with BSTFA
slide10

Ion fragments EI :

m/z=73, 75 [Si(CH3)3]+, [OH=Si(CH3)2]·+ relative intensity: (20-100%)

m/z =117 [COOSi(CH3)3]·+ monocarboxylic acids relative intensity: 61-97% (except aromatic carboxylic acids) and strong M-15 as well

m/z= 147 [(CH3)2Si=OSi(CH3)3]·+ 2 active H-atoms relative intensity: ~100%

m/z= 181 [C6F6CH2]+ carbonyl groups relative intensity 50-100%

/Yu et al. 1998/

slide12

181

147

117

planned time sc h edule of the work
Planned time schedule of the work
  • 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 -

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