Mass spectrometry parameters optimization for the 46 multiclass pesticides determination in strawberries with gas chromatography ion-trap tandem mass spectrometry

Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET),maximum excitation energy or “q” value (q), and isolationmass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit.Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

Analysis of PCBs in soils and sediments by microwave-assisted extraction, headspace-SPME and high resolution gas chromatography with ion-trap tandem mass spectrometry

A procedure for the determination of seven indicator PCBs in soils and sediments using microwave-assisted extraction (MAE) and headspace solid-phase microextraction (HS-SPME) prior to GC-MS/MS is described. Optimization of the HS-SPME was carried out for the most important parameters such as extraction time, sample volume and temperature. The adopted methodology has reduced consumption of organic solvents and analysis runtime. Under the optimized conditions, the method detection limit ranged from 0.6 to 1 ng/g when 5 g of sample was extracted, the precision on real samples ranged from 4 to 21% and the recovery from 69 to 104%. The proposed method, which included the analysis of a certified reference material in its validation procedure, can be extended to several other PCBs and used in the monitoring of soil or sediments for the presence of PCBs.

Rapid analysis of multiclass antibiotic residues and some of their metabolites in hospital, urban wastewater and river water by ultra-highperformance liquid chromatography coupled to quadrupole-linear ion trap tandem mass spectrometry

The present work describes the development of a fast and robust analytical method for the determination of 53 antibiotic residues, covering various chemical groups and some of their metabolites, in environmental matrices that are considered important sources of antibiotic pollution, namely hospital and urban wastewaters, as well as in river waters. The method is based on automated off-line solid phase extraction (SPE) followed by ultra-high-performance liquid chromatography coupled to quadrupole linear ion trap tandem mass spectrometry (UHPLC–QqLIT). For unequivocal identification and confirmation, and in order to fulfill EU guidelines, two selected reaction monitoring (SRM) transitions per compound are monitored (the most intense one is used for quantification and the second one for confirmation). Quantification of target antibiotics is performed by the internal standard approach, using one isotopically labeled compound for each chemical group, in order to correct matrix effects. The main advantages of the method are automation and speed-up of sample preparation, by the reduction of extraction volumes for all matrices, the fast separation of a wide spectrum of antibiotics by using ultra-high-performance liquid chromatography, its sensitivity (limits of detection in the low ng/L range) and selectivity (due to the use of tandem mass spectrometry) The inclusion of β-lactam antibiotics (penicillins and cephalosporins), which are compounds difficult to analyze in multi-residue methods due to their instability in water matrices, and some antibiotics metabolites are other important benefits of the method developed. As part of the validation procedure, the method developed was applied to the analysis of antibiotics residues in hospital, urban influent and effluent wastewaters as well as in river water samples

Characterization of gallotannins from Astronium species by flow injection analysis-electrospray ionization-ion trap-tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by flow injection analysis - Electrospray ionization ion trap tandem mass spectrometry and liquid chromatography/electrospray ionization mass spectrometry

The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

Chemical composition measurements of cloud condensation nuclei and ice nuclei by aerosol mass spectrometry

In this study the Aerodyne Aerosol Mass Spectrometer (AMS) was used during three laboratory measurement campaigns, FROST1, FROST2 and ACI-03. The FROST campaigns took place at the Leipzig Aerosol Cloud Interaction Simulator (LACIS) at the IfT in Leipzig and the ACI-03 campaign was conducted at the AIDA facility at the Karlsruhe Institute of Technology (KIT). In all three campaigns, the effect of coatings on mineral dust ice nuclei (IN) was investigated. During the FROST campaigns, Arizona Test Dust (ATD) particles of 200, 300 and 400 nm diameter were coated with thin coatings (< 7 nm) of sulphuric acid. At these very thin coatings, the AMS was operated close to its detection limits. Up to now it was not possible to accurately determine AMS detection limits during regular measurements. Therefore, the mathematical tools to analyse the detection limits of the AMS have been improved in this work. It is now possible to calculate detection limits of the AMS under operating conditions, without losing precious time by sampling through a particle filter. The instrument was characterised in more detail to enable correct quantification of the sulphate loadings on the ATD particle surfaces. Correction factors for the instrument inlet transmission, the collection efficiency, and the relative ionisation efficiency have been determined. With these corrections it was possible to quantify the sulphate mass per particle on the ATD after the condensation of sulphuric acid on its surface. The AMS results have been combined with the ice nucleus counter results. This revealed that the IN-efficiency of ATD is reduced when it is coated with sulphuric acid. The reason for this reduction is a chemical reaction of sulphuric acid with the particle's surface. These reactions are increasingly taking place when the aerosol is humidified or heated after the coating with sulphuric acid. A detailed analysis of the solubility and the evaporation temperature of the surface reaction products revealed that most likely aluminium sulphate is produced in these reactions.

Aircraft-based in-situ aerosol mass spectrometry: Chemical characterization and source identification of submicron particulate matter in the free and upper troposphere and lower stratosphere

The composition of the atmosphere is frequently perturbed by the emission of gaseous and particulate matter from natural as well as anthropogenic sources. While the impact of trace gases on the radiative forcing of the climate is relatively well understood the role of aerosol is far more uncertain. Therefore, the study of the vertical distribution of particulate matter in the atmosphere and its chemical composition contribute valuable information to bridge this gap of knowledge. The chemical composition of aerosol reveals information on properties such as radiative behavior and hygroscopicity and therefore cloud condensation or ice nucleus potential. rnThis thesis focuses on aerosol pollution plumes observed in 2008 during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) campaign over Greenland in June/July and CONCERT (Contrail and Cirrus Experiment) campaign over Central and Western Europe in October/November. Measurements were performed with an Aerodyne compact time-of-flight aerosol mass spectrometer (AMS) capable of online size-resolved chemical characterization of non-refractory submicron particles. In addition, the origins of pollution plumes were determined by means of modeling tools. The characterized pollution episodes originated from a large variety of sources and were encountered at distinct altitudes. They included pure natural emissions from two volcanic eruptions in 2008. By the time of detection over Western Europe between 10 and 12 km altitude the plume was about 3 months old and composed to 71 % of particulate sulfate and 21 % of carbonaceous compounds. Also, biomass burning (BB) plumes were observed over Greenland between 4 and 7 km altitude (free troposphere) originating from Canada and East Siberia. The long-range transport took roughly one and two weeks, respectively. The aerosol was composed of 78 % organic matter and 22 % particulate sulfate. Some Canadian and all Siberian BB plumes were mixed with anthropogenic emissions from fossil fuel combustion (FF) in North America and East Asia. It was found that the contribution of particulate sulfate increased with growing influences from anthropogenic activity and Asia reaching up to 37 % after more than two weeks of transport time. The most exclusively anthropogenic emission source probed in the upper troposphere was engine exhaust from commercial aircraft liners over Germany. However, in-situ characterization of this aerosol type during aircraft chasing was not possible. All long-range transport aerosol was found to have an O:C ratio close to or greater than 1 implying that low-volatility oxygenated organic aerosol was present in each case despite the variety of origins and the large range in age from 3 to 100 days. This leads to the conclusion that organic particulate matter reaches a final and uniform state of oxygenation after at least 3 days in the free troposphere. rnExcept for aircraft exhaust all emission sources mentioned above are surface-bound and thus rely on different types of vertical transport mechanisms, such as direct high altitude injection in the case of a volcanic eruption, or severe BB, or uplift by convection, to reach higher altitudes where particles can travel long distances before removal mainly caused by cloud scavenging. A lifetime for North American mixed BB and FF aerosol of 7 to 11 days was derived. This in consequence means that emission from surface point sources, e.g. volcanoes, or regions, e.g. East Asia, do not only have a relevant impact on the immediate surroundings but rather on a hemispheric scale including such climate sensitive zones as the tropopause or the Arctic.

Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make its deployment at sufficient sites to determine regional characteristics impractical. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2:5, and PM10, i.e., PM with aerodynamic diameters smaller than 1, 2.5, and 10 μm, respectively), collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g., AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60–91 %) achieved using this technique, together with low detection limits (0.8 μg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon ions, ions containing oxygen, and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning, and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g., filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved longterm data sets.

Characterization of urban aerosol in Cork city (Ireland) using aerosol mass spectrometry

Ambient wintertime background urban aerosol in Cork city, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the ca. 1 350 000 single particles characterized by an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS) were classified into five organic-rich particle types, internally mixed to different proportions with elemental carbon (EC), sulphate and nitrate, while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was characterized using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS) and was also found to comprise organic aerosol as the most abundant species (62 %), followed by nitrate (15 %), sulphate (9 %) and ammonium (9 %), and chloride (5 %). Positive matrix factorization (PMF) was applied to the HR-ToF-AMS organic matrix, and a five-factor solution was found to describe the variance in the data well. Specifically, "hydrocarbon-like" organic aerosol (HOA) comprised 20% of the mass, "low-volatility" oxygenated organic aerosol (LV-OOA) comprised 18 %, "biomass burning" organic aerosol (BBOA) comprised 23 %, non-wood solid-fuel combustion "peat and coal" organic aerosol (PCOA) comprised 21 %, and finally a species type characterized by primary m/z peaks at 41 and 55, similar to previously reported "cooking" organic aerosol (COA), but possessing different diurnal variations to what would be expected for cooking activities, contributed 18 %. Correlations between the different particle types obtained by the two aerosol mass spectrometers are also discussed. Despite wood, coal and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosol mass and non-refractory total PM1, respectively).Ambient wintertime background urban aerosol in Cork city, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the ca. 1 350 000 single particles characterized by an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS) were classified into five organic-rich particle types, internally mixed to different proportions with elemental carbon (EC), sulphate and nitrate, while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was characterized using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS) and was also found to comprise organic aerosol as the most abundant species (62 %), followed by nitrate (15 %), sulphate (9 %) and ammonium (9 %), and chloride (5 %). Positive matrix factorization (PMF) was applied to the HR-ToF-AMS organic matrix, and a five-factor solution was found to describe the variance in the data well. Specifically, "hydrocarbon-like" organic aerosol (HOA) comprised 20% of the mass, "low-volatility" oxygenated organic aerosol (LV-OOA) comprised 18 %, "biomass burning" organic aerosol (BBOA) comprised 23 %, non-wood solid-fuel combustion "peat and coal" organic aerosol (PCOA) comprised 21 %, and finally a species type characterized by primary m/z peaks at 41 and 55, similar to previously reported "cooking" organic aerosol (COA), but possessing different diurnal variations to what would be expected for cooking activities, contributed 18 %. Correlations between the different particle types obtained by the two aerosol mass spectrometers are also discussed. Despite wood, coal and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosol mass and non-refractory total PM1, respectively).

Das Aerosol-Ionenfallen-Massenspektrometer (AIMS) : Aufbau, Charakterisierung und Feldeinsatz

Um die in der Atmosphäre ablaufenden Prozesse besser verstehen zu können, ist es wichtig dort vorhandene Partikel gut charakterisieren zu können. Dazu gehört unter anderem die Bestimmung der chemischen Zusammensetzung der Partikel. Zur Analyse insbesondere organischer Partikel wurde dazu in einer früheren Promotion das Aerosol-Ionenfallen-Massenspektrometer (AIMS) entwickelt.Im Rahmen dieser Arbeit wurden Entwicklungsarbeiten durchgeführt, um die Charakteristiken des Prototypen zu verbessern sowie es für den Feldeinsatz tauglich zu machen. Die durchgeführten Veränderungen betreffen mechanische und elektrische Komponenten sowie das LabView Steuerungsprogramm. So wurde z.B. die Ionenquelle derart modifiziert, dass die Ionen nicht mehr permanent erzeugt werden, sondern nur innerhalb des Zeitraums wenn sie auch in der Ionenfalle gespeichert werden können. Durch diese Modifikation konnte das Signal-zu-Rausch Verhältnis deutlich verbessert werden. Nach Beendigung der Umbauten wurden in ausführlichen Laborstudien die einzelnen Instrumentenparameter detailliert charakterisiert. Neben den Spannungen die zur Fokussierung oder zur Speicherung der Ionen in der Ionenfalle dienen, wurden die unterschiedlichen Arten der resonanten Anregung, mittels der die Ionen in der Ionenfalle gezielt zu Schwingungen angeregt werden können, sehr genau untersucht. Durch eine gezielte Kombination der unterschiedlichen Arten der resonanten Anregung ist es möglich MSn-Studien durchzuführen. Nach erfolgreicher Charakterisierung konnte in weiteren Laborstudien die MSn-Fähigkeit des AIMS demonstriert werden. Für Tryptophan (C11H12N2O2) wurde anhand von MS4-Studien ausgehend von m/z 130 ein möglicher Fragmentierungsweg identifiziert. Für die einzelnen Stufen der MS4-Studien wurden die Nachweisgrenzen abgeschätzt. Im Rahmen der PARADE (PArticles and RAdicals: Diel observations of the impact of urban and biogenic Emissions) Messkampagne im August/September 2011 auf dem kleinen Feldberg in der Nähe von Frankfurt am Main wurde die Feldtauglichkeit des AIMS demonstriert. Die Nachweisgrenzen liegen für eine Mittelungszeit von 60 Minuten für Organik bei 1,4 µg m-3, für Nitrat bei 0,5 µg m-3 und für Sulfat bei 0,7 µg m-3, was ausreichend ist um atmosphärisches Aerosol messen zu können. Dies ist ein signifikanter Fortschritt im Vergleich zum Prototypen, der aufgrund schlechter Reproduzierbarkeit und Robustheit noch nicht feldtauglich war. Im Vergleich zum HR-ToF-AMS, einem Standard-Aerosolmassenspektrometer, zeigte sich, dass beide Instrumente vergleichbare Trends für die Spezies Nitrat, Sulfat und Organik messen.

Entwicklung, Aufbau und Charakterisierung eines neuartigen Ionenfallen-Massenspektrometers für Aerosolpartikel (AIMS)

Im Rahmen der Arbeit wurde ein neuartiges Aerosol-Ionenfallen-Massenspektrometer (AIMS) aufgebaut und umfassend charakterisiert. Mit dem AIMS kann die chemische Zusammensetzung der verdampfbaren Komponente (bei etwa 600 °C) von Aerosolpartikeln quantitativ und on-line bestimmt werden. Die Durchmesser der Teilchen, die analysiert werden können, liegen zwischen etwa 30 und 500 nm. Der experimentelle Aufbau greift auf ein bereits gut charakterisiertes Einlasssystem des Aerodyne Aerosol-Massenspektrometers (AMS) zurück, das einen Partikeleinlass, bestehend aus einer kritischen Düse und einer aerodynamischen Linse, einen Verdampfer für die Aerosolteilchen und eine Elektronenstoß-Ionenquelle enthält. Das kommerzielle AMS verwendet entweder ein lineares Quadrupol-Massenfilter (Q-AMS) oder ein Flugzeit-Massenspektrometer (ToF-AMS). Im AIMS hingegen wird eine dreidimensionale Ionenfalle als Massenanalysator eingesetzt. Dadurch eröffnen sich unter anderem Möglichkeiten zur Durchführung von MSn-Studien und Ionen/Molekül-Reaktionsstudien. Das Massenspektrometer und wichtige Teile der Steuerungselektronik wurden am Max-Planck-Institut für Chemie in Mainz entworfen und hergestellt. Das AIMS wird von einem PC und einer Software, die in der Programmiersprache LabVIEW verfasst ist, gesteuert. Aufgrund seiner Kompaktheit ist das Instrument auch für den Feldeinsatz geeignet. Mit der Software Simion 7.0 wurden umfangreiche Simulationsstudien durchgeführt. Diese Studien beinhalten Simulationen zur Ermittlung der optimalen Spannungseinstellungen für den Ionentransfer von der Ionenquelle in die Ionenfalle und eine Abschätzung der Sammeleffizienz der Ionenfalle, die gut mit einem gemessenen Wert übereinstimmt. Charakterisierungsstudien zeigen einige instrumentelle Merkmale des AIMS auf. Es wurde beispielsweise ein Massenauflösungsvermögen von 807 für m/z 121 gefunden, wenn eine Analyserate von 1780 amu/s verwendet wird. Wird die Analyserate verringert, dann lässt sich das Massenauflösungsvermögen noch erheblich steigern. Bei m/z 43 kann dann ein Wert von > 1500 erzielt werden, wodurch sich Ionenfragmente wie C2H3O+ (m/z 43.0184) und C3H7+ (m/z 43.0548) voneinander trennen lassen. Der Massenbereich des AIMS lässt sich durch resonante Anregung erweitern; dies wurde bis zu einer Masse von 1000 amu getestet. Kalibrationsmessungen mit laborgenerierten Partikeln zeigen eine hervorragende Linearität zwischen gemessenen Signalstärken und erzeugten Aerosol-Massenkonzentrationen. Diese Studien belegen im Zusammenhang mit den gefundenen Nachweisgrenzen von Nitrat (0.16 μg/m³) und Sulfat (0.65 μg/m³) aus Aerosolpartikeln, dass das AIMS für quantitative Messungen von atmosphärischem Aerosol geeignet ist. Ein Vergleich zwischen dem AIMS und dem Q-AMS für Nitrat in städtischem Aerosol zeigt eine gute Übereinstimmung der gefundenen Messwerte. Für laborgenerierte Polystyren-Latexpartikel wurde eine MS/MS-Studie unter der Anwendung von collision induced dissociation (CID) durchgeführt. Das Verhältnis von Fragmentionen zu Analytionen wurde zu einem Wert von > 60% bestimmt. In der Zukunft können ähnliche MS/MS-Studien auch für atmosphärische Aerosolpartikel angewandt werden, wodurch sich neue Perspektiven für die Speziation von Aerosolbestandteilen eröffnen. Dann sollen vor allem Kondensationsprozesse, das heißt die Bildung von sekundärem Aerosol, detailliert untersucht werden.

Enhancing non-refractory aerosol apportionment from an urban industrial site through receptor modelling of complete high time-resolution aerosol mass spectra

Receptor modelling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada’s CRUISER mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach was compared to the more common method of analysing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulphate and oxygenated organic aerosol containing factor (Sulphate-OA); an ammonium nitrate and oxygenated organic aerosol containing factor (Nitrate-OA); an ammonium chloride containing factor (Chloride); a hydrocarbon like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analysing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case, an Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this method would be even more useful for HR-ToF-AMS data, due to the ability to better understand the chemical nature of atypical factors from high resolution mass spectra. Second, utilizing PMF to extract factors containing inorganic species allowed for the determination of extent of neutralization, which could have implications for aerosol parameterization. Third, subtler differences in organic aerosol components were resolved through the incorporation of inorganic mass into the PMF matrix. The additional temporal features provided by the inorganic aerosol components allowed for the resolution of more types of oxygenated organic aerosol than could be reliably re-solved from PMF of organics alone. Comparison of findings from the PMFFull MS and PMFOrg MS methods showed that for the Windsor airshed, the PMFFull MS method enabled additional conclusions to be drawn in terms of aerosol sources and chemical processes. While performing PMFOrg MS can provide important distinctions between types of organic aerosol, it is shown that including inorganic species in the PMF analysis can permit further apportionment of organics for unit mass resolution AMS mass spectra.

Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal-optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R-2 = 0.67-0.78), and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA/EC ratios. Aged biomass burning OA (OOA(2)-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the temporal behaviour and chemical composition of the ATOFMS classes also enabled estimation of the relative contribution of transported emissions of each chemical species and total particle mass in the size range investigated. Only 22% of the total ATOFMS-derived particle mass was apportioned to fresh, local emissions, with 78% apportioned to regional/continental-scale emissions. Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal-optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R-2 = 0.67-0.78), and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA/EC ratios. Aged biomass burning OA (OOA(2)-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the temporal behaviour and chemical composition of the ATOFMS classes also enabled estimation of the relative contribution of transported emissions of each chemical species and total particle mass in the size range investigated. Only 22% of the total ATOFMS-derived particle mass was apportioned to fresh, local emissions, with 78% apportioned to regional/continental-scale emissions.