Functional group monitoring in atmospheric particulate organic matter using tandem
mass spectrometry: principles and applications
N. Marchand, J. Dron, I. El Haddad and H. Wortham
Laboratoire Chimie Provence (UMR 6264), équipe Instrumentation et Réactivité Atmosphérique, Universités d'Aix-Marseille I,II et III-
3 place Victor Hugo, 13331 Marseille Cedex 3
Particulate organic matter (POM) in atmospheric under study (figure 1) (ii) a high accuracy
aerosols results from primary emissions as well as in quantification of the functional groups (iii) low
situ formation through oxidative processes of gas- detection limits allowing applications to
phase organic compounds, and contributes in environmental measurements.
approximately 20 to 50% of the total fine aerosol Results obtained by this new approach for a wide
mass at continental mid-latitude. It has been well panel of atmospheric samples including primary
established that this class of particulate material has a sources (vehicular exhaust, wood combustions), SOA
high potential impact on both human health and (photo oxidation of xylene), and urban background
climate change. In order to better estimate the aerosols collected during winter and summer will be
influence of organic aerosols, a good knowledge of presented and compared in terms of functionalisation
their composition and reactivity is required. degree.
However, considering the degree of complexity of
Arbitrary Units (kCps)
POM, conventional analytical methods lead to its 75 62 (394 kCps) a) Precursor ions of NO2-
incomplete characterization. -NO2 C= 10,7 pmol/µgPM10
Functional group determination is a complementary 50
RfOC ~ 2300
approach between molecular identification and
organic carbon measurements which enables the 25
characterization of a larger fraction of the aerosol
mass and provides valuable information on its 100 200 300 400 500
Arbitrary Units (kCps)
chemical composition. This analytical technique
b) Precursor ions of NO3-
being besides the best suited for modelling purposes,
it appears imperative to improve its performances. 100
Also, Fourier Transform Infrared spectroscopy (FT-
IR) suffers from poor robustness (Blando, 2001),
proton nuclear magnetic resonance (H-NMR)
(Tagliavini, 2006) requires heavy instrumentation,
100 200 300 400 500 600
and both have a relatively low sensibility. m/z
Intensity (arb. units
c) 307 335 C= 30,3 pmol/µgPM10
The aim of the work presented here is to propose a
449 RfOC ~ 500
new method for the analysis of functional groups and 30 407 421
to highlight its relevance for atmospheric chemistry 365
purposes. This new atmospheric pressure chemical 20
ionization-tandem mass spectrometry (APCI- 279 297
MS/MS) methodology is based either on neutral loss 10
291 344 387
mode for carboxylic acid and carbonyl functional 251
group (Dron et al, 2007, 2008a) either on precursor 0
200 300 400 500
m/z 6 0 0
ion scanning mode for nitro functional group (Dron Dron el al, JMS, 2008
et al, 2008b). These approaches enable to group
chemical compounds by their ability to loose a
Figure 1. Mass spectra obtained for –NO2 (PAR 46), -
known neutral molecular fragment for neutral loss
ONO2 (PAR 62) and C=O (NL 181) of a sample collected
mode (NL mode) or to produce a characteristic ion in at an urban background site (Chamonix, France) during
the collision cell for the precursor ion scanning mode summer. RfOC represents the functionalisation of the
(PAR mode). For example, after having been organic carbon (=nOC/nfunct.)
derivatized to methyl esters, carboxylic acids are
identified by their ability to loose a HOCH3 fragment Blando, J. D., Porcja R. J. & Turpin B. J. (2001). Aerosol Sci.
(Dron et al, 2007) while the nitro compounds are Technol., 35, 899-908.
Tagliavini, E., Moretti F., Decesari S., Facchini M. C., Fuzzi S.,
analysed according to their ability to produce NO2- Maenhaut W. (2006). Atmos. Chem. Phys., 6, 1003-1019.
(m/z=46 amu) in the collision cell (Dron et al, Dron. J., Eyglunent G., Temime-Roussel B., Marchand N.,
2008b). Compared to FT-IR and H-NMR Wortham H. (2007). Caboxylic., Analytica Chimica Acta ,
spectroscopy, this analytical strategy offers major 605(1), 61-69.
Dron. J., Zheng W., Marchand N., Wortham H. 2008a. Journal of
benefits, it provides (i) an apparent molecular weight Mass Spectrometry, in press.
distribution of the compounds bearing the function Dron. J., Abidi E., El Haddad, I., Marchand N., Wortham H.
2008b.. Submitted to Analytical Chemistry (Fev 2008).