My current research focus is on developing methods for chemical characterization of the organic composition of particulate matter which encompasses coupled chromatographic techniques for target analysis of polycyclic aromatic compounds (PACs), and nontarget analytical workflows using high-resolution mass spectrometry.

Ongoing research projects

Chemical profiling and toxicological assessment of organic aerosols from traffic - Necessary knowledge for improved risk assessments and regulations
Formas DNr. 2021-00496, 2022-2025.

Abstract

Air pollution, which include hazardous gases and particles, causes staggering economical losses and is the largest environmental health risk factor for disease and pre-mature death. Road traffic is a large source to particles, black carbon and hazardous polycyclic aromatic compounds, and is thought to be responsible for a substantial portion of the total pre-mature deaths caused by particles. Vehicular particle emissions comprise tail-pipe emissions, different wear particles and road dust re-suspension.

Research on vehicular emissions is mostly conducted on a single vehicle or a single engine whose emissions are difficult to extrapolate to the diverse vehicle fleet actually running on the roads. To address this issue, this project will conduct sampling of collectively emitted traffic related PM10 and PM2.5 close to a heavily trafficked highway for the timespan of a whole year.

The organic fraction present on the collected particles will be characterized using nontarget analytical chemical methods using complementary instrumental techniques to obtain a comprehensive chemical profile of the organic fraction emitted from vehicular traffic. Combined chemical analyses and in vitro assays will be made to identify health relevant traffic related organic chemical compounds.

In order reduce the negative health impact from road traffic emissions it is of necessity to understand the composition of these emissions and the health risks associated with those emissions.

Project members:

Ioannis Sadiktsis (Principal Investigator), MMK, Stockholm University
Kristian Dreij, Institute of Environmental Medicine (IMM), Karolinska Institute
Oskar Karlsson, Science for Life Laboratory & Department of Environmental Science, Stockholm University
 

Azo dyes, quinolines and anilines in clothes - Daily human exposure to hazardous chemicals

Formas 2021-01540, 2022-2025.

Abstract

The global textile industry utilizes high amounts of numerous chemicals. We have observed that quinolines and anilines are compounds that often are found at high levels in clothing garments on the consumer market. The compounds are most likely by-products from disperse azo dyes, used for colouring synthetic materials such as polyester. Many of these chemicals have proven or suspected carcinogenic, mutagenic and/or skin allergenic effects, and according to preliminary results, the chemicals may stay in the garments even after several laundry cycles. We have detected levels exceeding 1 gram/kilogram in certain common clothes. Azo dyes and anilines are suspected to a play important role in textile allergy, but it is not fully known why and how. Firstly, knowledge is lacking regarding which azo dyes and anilines that are actually present in textiles on the consumer market, and at what levels. Also, it is not known how easily they can be taken up by human skin from skin-close garments. We will therefore examine skin absorption using a synthetic skin model (having similar properties as human skin), and also investigate if even more hazardous chemicals may be formed by skin enzymes. Also, we will use novel and powerful analytical tools to map the occurrence of anilines, quinolines and azo dyes in both new and recycled clothing textiles. Reuse of textiles that is safe to humans and the environment is a prerequisite for a sustainable circular economy of clothes.

Project members:
Ulrika Nilsson (Principal Investigator), MMK, Stockholm University
Ioannis Sadiktsis, MMK, Stockholm University
Conny Östman, MMK, Stockholm University
 

A new model for assessing cancer risks associated with air pollution mixtures
Formas DNr. 2019-00582, 2020–2022.

Abstract

Air pollution and airborne particulate matter (PM) are classified as carcinogenic to humans, but these complex mixtures of multiple compounds makes quantitative risk assessment a challenge. Current strategies for cancer risk assessment of air pollution are based on a pollutant-by-pollutant approach. This is clearly a simplification which excludes the possibility of interaction effects and may misestimate the actual cancer risk. Here, we address this issue by developing new methodology for whole mixture-based cancer risk assessment of air pollution. The overall aim of this project is to combine state-of-the-art methods for analysis of chemical composition of urban, diesel and biomass burning PM with traditional and high throughput in vitro testing of native PM samples in order to generate Mixture Potency Factors (MPF) estimating the carcinogenic potency of the whole mixture. Our results show that MPFs based on whole mixtures better indicate cancer potency than looking at single pollutants. The project will develop an approach that can be used for assessment of total carcinogenic effects of air PM pollution both for larger city-wide and for smaller site-specific risk assessments. Ultimately, we will improve the cancer risk assessment of airborne PM by including the obtained knowledge about whole mixture potencies in already established models for estimation of lung cancer incidence in urban environments.

Project members:
Kristian Dreij (Principal Investigator), Institute of Environmental Medicine (IMM), Karolinska Institute
Felipe De Oliveira Galvão, IMM, Karolinska Institute
Ulla Stenius, IMM, Karolinska Institute
Silvia Batistuzzo de Medeiros, Federal University of Rio Grande do Norte, Brazil,  Department of Cellular Biology and Genetics
Ioannis Sadiktsis, MMK, Stockholm University
Joakim Pagels, Ergonomics and Aerosol Technology, Lund University
Hanna Karlsson, IMM, Karolinska Institute
 

Chemical characterizations of diesel engine exhaust particles and its transformation products from renewable fuels
Formas DNr. 2018-00475, 2019–2021.

Abstract

The link between ambient particle exposure and cardiopulmonary diseases, as well as lung cancer is well established from numerous of epidemiological studies. Although not fully understood, several important factors for particle toxicity have been suggested. These include particle size, surface reactivity, and organic composition. Polycyclic aromatic compounds (PACs) has received special attention due to their carcinogenic properties and abilities to generate reactive oxygen species, thus being likely candidates among organic compounds that are driving the adverse health effects.

Vehicular traffic and in particular diesel engine exhaust is an important contributor to both fine particles and PACs in urban atmospheres. Thus, with the near future transition from fossil fuels to bio-based alternatives, implications to adverse health effects from these potentially new emissions needs to be further investigated.

This research proposal describes analytical workflows involving powerful instrumental techniques that enable us to thoroughly characterize the chemical composition of heavy-duty-diesel emission particles. Planned investigations on the how the emissions change with different biofuels, atmospheric aging and the use of emissions control techniques is expected to generate valuable data for improving future health risk assessments, air pollution modelling, and emission mitigation strategies where the long-term goal is to improve the public health.

Project members:
Ioannis Sadiktsis (Principal Investigator), MMK, Stockholm University
Joakim Pagels, Ergonomics and Aerosol Technology, Lund University

 

Past research projects

Screening of potentially toxic compounds and total toxicity of PM10 aerosols
Naturvårdsverket (Miljögiftssamordning), 2019–2020.

The purpose of this screening study is to assess spatial and temporal variations in oxidative stress, PAH, quinones and nitro-PAH in PM10 samples from rural, urban and traffic sites. One important question is if there is any relation between toxicity and concentrations of PAH, quinones and nitro-PAH. Other pollutants measured at these sites, like ozone, black carbon, PM10 and particle number concentration, will also be included in the evaluation.

Project members:
Christer Johansson (Project leader), ACES, Stockholm University
Zahra Hamzavi, ACES, Stockholm University
Ondrej Tesar, ACES, Stockholm University
Ioannis Sadiktsis, MMK, Stockholm University
Kristian Dreij, IMM, Karolinska Institute
Sanna Silvergren, SLB-analys

A selection from Stockholm University publication database

• Polycyclic aromatic compounds in particulate matter and indoor dust at preschools in Stockholm, Sweden: Occurrence, sources and genotoxic potential in vitro

  2020. Hwanmi Lim (et al.). Science of the Total Environment

  Article

  Children spend a significant amount of their day in preschool; thus, environmental quality at preschools may have an impact on children’s health. In the present study, we analyzed polycyclic aromatic compounds (PACs), including PAHs, alkylated PAHs and oxygenated PAHs (OPAHs), in indoor and outdoor air particulate matter (PM₁₀) and indoor dust at preschools in Stockholm, Sweden. There were significant correlations between PAC levels in outdoor and indoor PM₁₀, with in general higher PAC levels outdoors. Fluoranthene and pyrene were detected at highest levels in all sample types, although phenanthrene and methylated phenanthrene derivatives also were found at high levels in indoor dust. In addition, the highly carcinogenic PAHs 7H-benzo[c]fluorene, 7,12-dimethylbenz[a]anthracene, benz[j]aceanthrylene, and dibenzo[a,l]pyrene were detected in some samples. Benzanthrone was the most prevalent OPAH in PM₁₀ samples and 9,10-anthraquinone in indoor dust. Based on diagnostic ratios and Positive Matrix Factorization we identified vehicle emission and biomass burning as important PAC sources for all samples analyzed. However, poor correlation between PAC levels in indoor PM₁₀ and indoor dust suggested additional sources for the latter. Measuring activation of DNA damage signaling in human cells exposed to organic extracts of the samples indicated substantial genotoxic potential of outdoor PM₁₀ and indoor dust. Determination of benzo[a]pyrene equivalents demonstrated that the highly potent PAHs benz[j]aceanthrylene and dibenz[a,h]anthracene contributed more than 20% to the total carcinogenic potency of the samples. We conclude that PAC levels at Stockholm preschools are relatively low but that outdoor air quality may impact on the indoor environment.

  Read more about Polycyclic aromatic compounds in particulate matter and indoor dust at preschools in Stockholm, Sweden: Occurrence, sources and genotoxic potential in vitro

• Genotoxicity and DNA damage signaling in response to complex mixtures of PAHs in biomass burning particulate matter from cashew nut roasting

  2019. Marcos Felipe de Oliveira Galvão (et al.). Environmental Pollution

  Article

  Approximately 3 billion people world-wide are exposed to air pollution from biomass burning. Herein, particulate matter(PM) emitted from artisanal cashew nut roasting, an important economic activity worldwide, was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-) PAHs; ii) intracellular levels of reactive oxygen species (ROS); iii) genotoxic effects and time- and dose-dependent activation of DNA damage signaling, and iv) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair, using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8–10 ng/m3), while benzanthrone and 9,10-anthraquinone were the most abundant oxy-PAHs. Testing of PM extracts was based on B[a]P equivalent doses (B[a]Peq). IC50 values for viability were 5.7 and 3.0 nM B[a]Peq at 24 h and 48 h, respectively. At these low doses, we observed a time- and dose-dependent increase in intracellular levels of ROS, genotoxicity (DNA strand breaks) and DNA damage signaling (phosphorylation of the protein checkpoint kinase 1 – Chk1). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no previous study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro, in lung cells exposed to cashew nut roasting extracts. Sustained induction of expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), ROS and pro-inflammatory response (IL-8, TNF-α, IL-2,COX2), and DNA damage response (CDKN1A and DDB2) was also identified. In conclusion, our data show high potency of cashew nut roasting PM to induce cellular stress including genotoxicity, and more potently when compared to B[a]P alone. Our study provides new data that will help elucidate the toxic effects of low-levels of PAH mixtures from air PM generated by cashew nut roasting.

  Read more about Genotoxicity and DNA damage signaling in response to complex mixtures of PAHs in biomass burning particulate matter from cashew nut roasting

• A two-dimensional non-comprehensive reversed/normal phase high-performance liquid chromatography/tandem mass spectrometry system for determination of limonene and linalool hydroperoxides

  2018. Ahmed Ramzi (et al.). Journal of Chromatography A 1566, 102-110

  Article

  A two-dimensional non-comprehensive high-performance liquid chromatographic (HPLC) system coupled to electrospray ionization tandem mass spectrometry was developed for the determination of skin allergenic hydroperoxides of limonene and linalool. These compounds are some major components behind skin sensitization and contact (skin) allergy to fragrances.

  Fragrance hydroperoxides usually occur in complex compositions, often as constituents of the natural essential oils added to a large number of commercial products. Their similarities to interfering compounds, many with identical elemental composition, make the determination difficult even when using selective detection methods like mass spectrometry. In this work, a first-dimension chromatographic heart-cut isolation of the hydroperoxides on a reversed-phase HPLC system was combined with a second-dimension normal-phase HPLC system for separation of the hydroperoxides. The intersystem transfer was made by trapping the heart-cut fraction on a short graphitized carbon column, exchanging the mobile phase and back-flushing the hydroperoxides into the second dimension.

  Each analysis was performed within 60 min without any pretreatment, except dilution, prior to injection. The obtained instrumental limits of detection (LODs) at a signal-to-noise ratio of 3 were lower than 1.2 ng injected on column and method LODs were below 0.3 ppm. An after-shave product was shown to contain the highest concentrations of the measured hydroperoxides, with 445 ± 23 ppm of total linalool hydroperoxides. This level is likely able to elicit skin reactions in already sensitized individuals.

  Read more about A two-dimensional non-comprehensive reversed/normal phase high-performance liquid chromatography/tandem mass spectrometry system for determination of limonene and linalool hydroperoxides

• Time-resolved analysis of particle emissions from residential biomass combustion – Emissions of refractory black carbon, PAHs and organic tracers

  2017. Ingeborg E. Nielsen (et al.). Atmospheric Environment 165, 179-190

  Article

  Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of refractory black carbon, such as absorption enhancement by lensing.

  Read more about Time-resolved analysis of particle emissions from residential biomass combustion – Emissions of refractory black carbon, PAHs and organic tracers

• Physical and chemical properties of RME biodiesel exhaust particles without engine modifications

  2016. Robin Nyström (et al.). Fuel 186, 261-269

  Article

  A major contributor to ambient particulate air pollution is exhaust from diesel engines and other vehicles,which can be linked to different adverse health effects. During the last decades, a global drive towardsfinding sustainable and clean bio-based alternative fuels for the transport sector has taken place and biodieselis one of the most established alternatives today. To better assess the overall effects on a publichealth level when introducing biodiesel and other renewable fuels, a better understanding of the detailedexhaust particle properties, is needed. In this work, the physical and chemical properties of biodieselexhaust particles were studied in comparison to standard diesel exhaust emissions, in an existing enginewithout modifications, focusing on particulate carbonaceous matter and PAH/Oxy-PAH as well as fineparticle size distribution. An older off-road engine, produced between 1996 and 2004, was used withthree different fuels/fuel blends; (1) 100 wt% low-sulfur standard petro diesel (SD), (2) 100 wt% rapeseedmethyl ester biodiesel (B100) and (3) a blended fuel – B30 consisting of 30 wt% RME and 70 wt% SD. Thestudy focused mainly on emissions from transient engine operation, but includes also idling conditions.The gaseous emissions measured for the biodiesel fuel were in general in accordance with previousreported data in the literature, and compared to the standard petro diesel the emissions of CO was lowerwhile NO_x emissions increased. The particulate mass concentration during transient operation wasalmost halved compared to when petro diesel was used and this was associated with a decrease in averageparticle size. The shift in particle mass and size was associated with a higher fraction of organic matterin general, considerable less PAH’s but a relative higher fraction of Oxy-PAH’s, when shifting frompetro diesel to biodiesel.

  Read more about Physical and chemical properties of RME biodiesel exhaust particles without engine modifications

• Removal of polycyclic aromatic hydrocarbons and genotoxic compounds in urban air using air filter materials for mechanical ventilation in buildings

  2016. Ioannis Sadiktsis (et al.). Science and Technology for the Built Environment 22 (3), 346-355

  Article

  Humans spend most of their lives in indoor environments; hence, indoor exposure to air pollution may constitute a large part of the total exposure to air pollution. Polycyclic aromatic hydrocarbons are well known for their mutagenicity and carcinogenicity and are ubiquitous in urban environments as a result of combustion from e.g. vehicular traffic. Polycyclic aromatic hydrocarbons associated to air particulate matter in indoor environments originates from several sources including: cooking and heating, outdoor sources, smoking, candle and incense burning. Infiltration has been suspected to be one major source of indoor polycyclic aromatic hydrocarbons. In this study, four different air filter materials intended for mechanical ventilation were tested for their capability to remove particle bound polycyclic aromatic hydrocarbons and other genotoxic compounds from a real urban aerosol. Particles were sampled at two highly trafficked locations in Stockholm using a sampling system capable of sample particles in parallel, thus allowing sampling of filtered and un-filtered air simultaneously. The sampled particles were extracted and analysed for polycyclic aromatic hydrocarbons and the genotoxicity of the organic extract was determined using Ames mutagenicity tests. Each air filters capability of removing polycyclic aromatic hydrocarbons and reducing genotoxic effects was determined by comparing the filtered and un-filtered air samples. The results showed that all air filter materials had the capability of removing polycyclic aromatic hydrocarbons and reduce genotoxic effects downstream the air filter, and that the magnitude of the reduction was correlated with the standardized particulate collection efficiencies of a 0.4 μm particles for the tested air filter materials. However, the filter with the lowest performance did not significantly reduce direct acting mutagens.

  Read more about Removal of polycyclic aromatic hydrocarbons and genotoxic compounds in urban air using air filter materials for mechanical ventilation in buildings

• Class separation of lipids and polycyclic aromatic hydrocarbons in normal phase high performance liquid chromatography - A prospect for analysis of aromatics in edible vegetable oils and biodiesel exhaust particulates

  2014. Petter Olsson (et al.). Journal of Chromatography A 1360, 39-46

  Article

  The retention characteristics of the major lipid components in biodiesels and edible oils as well as representative polycyclic aromatic compounds (PAHs) have been investigated on five different normal phase HPLC stationary phases, in order to optimize class separation for an automatized online HPLC cleanup of PAHs prior GC-MS analysis. By stepwise comparison of different hexane/MTBE compositions as mobile phases on cyano-, phenyl-, pentabromobenzyl-, nitrophenyl- and amino- modified silica columns, the capacity and selectivity factors for each analyte and column could be calculated. It was concluded that the most suitable column for backflush isolation of PAHs in biodiesel and edible oil matrices was the pentabromobenzyl-modified silica (PBB). A previously described online HPLC-GC-MS system using the PBB column was then evaluated by qualitative and quantitative analysis of a biodiesel exhaust particulate extract and a vegetable oil reference material. The GC-MS full scan analysis of the biodiesel particulate extract showed that the lipids had been removed from the sample and a fraction containing PAHs and oxygenated derivatives thereof had been isolated. Quantified mass fractions of PAHs of the reference material BCR-458 agreed well for most of the certified PAH mass fractions in the spiked coconut oil reference material.

  Read more about Class separation of lipids and polycyclic aromatic hydrocarbons in normal phase high performance liquid chromatography - A prospect for analysis of aromatics in edible vegetable oils and biodiesel exhaust particulates

• Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters

  2014. Amanda L Hunter (et al.). Particle and Fibre Toxicology 11 (62)

  Article

  Background

  Myocardial infarction is the leading cause of death in fire fighters and has been linked with exposure to air pollution and fire suppression duties. We therefore investigated the effects of wood smoke exposure on vascular vasomotor and fibrinolytic function, and thrombus formation in healthy fire fighters.

  Methods

  In a double-blind randomized cross-over study, 16 healthy male fire fighters were exposed to wood smoke (~1 mg/m3 particulate matter concentration) or filtered air for one hour during intermittent exercise. Arterial pressure and stiffness were measured before and immediately after exposure, and forearm blood flow was measured during intra-brachial infusion of endothelium-dependent and -independent vasodilators 4–6 hours after exposure. Thrombus formation was assessed using the ex vivo Badimon chamber at 2 hours, and platelet activation was measured using flow cytometry for up to 24 hours after the exposure.

  Results

  Compared to filtered air, exposure to wood smoke increased blood carboxyhaemoglobin concentrations (1.3% versus 0.8%; P < 0.001), but had no effect on arterial pressure,augmentation index or pulse wave velocity (P > 0.05 for all). Whilst there was a dose-dependent increase in forearm blood flow with each vasodilator (P < 0.01 for all), there were no differences in blood flow responses to acetylcholine, sodium nitroprusside or verapamil between exposures (P > 0.05 for all). Following exposure to wood smoke, vasodilatation tobradykinin increased (P = 0.003), but there was no effect on bradykinin-induced tissue-plasminogen activator release, thrombus area or markers of platelet activation (P > 0.05 for all).

  Conclusions

  Wood smoke exposure does not impair vascular vasomotor or fibrinolytic function, or increase thrombus formation in fire fighters. Acute cardiovascular events following firesuppression may be precipitated by exposure to other air pollutants or through other mechanisms, such as strenuous physical exertion and dehydration.

  Read more about Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters

• Particulate associated polycyclic aromatic hydrocarbon exhaust emissions from a portable power generator fueled with three different fuels – A comparison between petroleum diesel and two biodiesels

  2014. Ioannis Sadiktsis (et al.). Fuel 115, 573-580

  Article

  The fuel impact on the emission of more than 40 particulate associated polycyclic aromatic hydrocarbons (PAHs) in the molecular weight range 178–302 Da were investigated. The fuels; neat diesel (EN 590), rape seed methyl ester (B100) and a 30% w/w blend thereof (B30) were tested on a portable power generator without any exhaust aftertreatment. Gaseous emissions of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO_x) were measured along with particulate emissions and its size distribution for the different fuels. Collected diesel particles were extracted using pressurized fluid extraction and analyzed using an online hyphenated liquid chromatography–gas chromatography–mass spectrometry system.

  The neat B100 and the B30 fuel produced less CO and total PAHs while the emissions of NO_x and particulate matter increased compared with petroleum diesel fuel per kW h. The reduction of PAH emissions of the alternative diesel fuels were 36% and 70% for B30 and B100 respectively. While the PAH profiles for the neat diesel fuel and B30 were similar, the profile of B100 differed in the sense that the emission contained a higher percentage of PAHs with higher molecular weights. The emission of these PAHs was however larger using the neat diesel fuel with the exception for some of these higher molecular weight PAHs of which there was an increased emission using B100. Thermogravimetric analysis revealed that the collected particles from B100 contained a substantial amount of volatile components. A mass spectrometric full scan analysis suggests that these volatile components are in fact unburned or partially-burned fuel constituents.

  It is concluded that the particles originating from biodiesel combustion might be very different from those originating from petroleum diesel combustion which places new demands on the development of measurement methodologies originally developed for particulate emissions from petroleum-based fuels.

  Read more about Particulate associated polycyclic aromatic hydrocarbon exhaust emissions from a portable power generator fueled with three different fuels – A comparison between petroleum diesel and two biodiesels

• Tire tread wear particles in ambient air—a previously unknown source of human exposure to the biocide 2-mercaptobenzothiazole

  2014. Rozanna Avagyan (et al.). Environmental science and pollution research international 21 (19), 11580-11586

  Article

  Urban particulate matter (PM), asphalt, and tire samples were investigated for their content of benzothiazole and benzothiazole derivates. The purpose of this study was to examine whether wear particles, i.e., tire tread wear or road surface wear, could contribute to atmospheric concentrations of benzothiazole derivatives. Airborne particulate matter (PM₁₀) sampled at a busy street in Stockholm, Sweden, contained on average 17 pg/m³ benzothiazole and 64 pg/m³ 2-mercaptobenzothiazole, and the total suspended particulate-associated benzothiazole and 2-mercaptobenzothiazole concentrations were 199 and 591 pg/m³, respectively. This indicates that tire tread wear may be a major source of these benzothiazoles to urban air PM in Stockholm. Furthermore, 2-mercaptobenzothiazole was determined in urban air particulates for the first time in this study, and its presence in inhalable PM₁₀ implies that the human exposure to this biocide is underestimated. This calls for a revision of the risk assessments of 2-mercaptobenzothiazole exposure to humans which currently is limited to occupational exposure.

  Read more about Tire tread wear particles in ambient air—a previously unknown source of human exposure to the biocide 2-mercaptobenzothiazole

• Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry

  2013. Rozanna Avagyan (et al.). Journal of Chromatography A 1307, 119-125

  Article

  A high performance liquid chromatography–tandem mass spectrometry method utilizing electrospray ionization in positive and negative mode has been developed for the separation and detection of benzothiazole and benzotriazole derivates. Ultra-sonication assisted solvent extraction of these compounds has also been developed and the overall method demonstrated on a selected clothing textile and an automobile tire sample. Matrix effects and extraction recoveries, as well as linearity and limits of detection have been evaluated. The calibration curves spanned over more than two orders of magnitude with coefficients of correlation R² > 0.99 and the limits of detection and the limits of quantification were in the range 1.7–58 pg injected and 18–140 pg/g, respectively. The extraction recoveries ranged between 69% and 102% and the matrix effects between 75% and 101%. Benzothiazole and benzotriazole derivates were determined in the textile sample and benzothiazole derivatives determined in the tire sample with good analytical performance.

  Read more about Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry

• Automobile Tires-A Potential Source of Highly Carcinogenic Dibenzopyrenes to the Environment

  2012. Ioannis Sadiktsis (et al.). Environmental Science and Technology 46 (6), 3326-3334

  Article

  Eight tires were analyzed for 15 high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAN), using pressurized fluid extraction. The variability of the PAIR concentrations determined between different tires was large; a factor of 22.6 between the lowest and the highest. The relative abundance of the analytes was quite similar regardless of tire. Almost all (92.3%) of the total extractable PAH content was attributed to five PAHs: benzo[ghi]perylene, coronene, indeno[1,2,3-cd]pyrene, benzo[e]pyrene, and benzo[a]pyrene. The difference in the measured PAIR content between summer and winter tires varied substantially across manufacturers, making estimates of total vehicle fleet emissions very uncertain. However, when comparing different types of tires from the same manufacturer they had significantly (p = 0.05) different PAH content. Previously, there have been no data available for carcinogenic dibenzopyrene isomers in automobile tires. In this study, the four dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene constituted <2% of the sum of the 15 analyzed HMW PAHs. These findings show that automobile tires may be a potential previously unknown source of carcinogenic dibenzopyrenes to the environment.

  Read more about Automobile Tires-A Potential Source of Highly Carcinogenic Dibenzopyrenes to the Environment

• Comparing columns for gas chromatography with the two-parameter model for retention prediction

  2011. Yasar Thewalim, Ioannis Sadiktsis, Anders Colmsjö. Journal of Chromatography A 1218 (31), 5305-5310

  Article

  The retention times of selected compounds in temperature programmed gas chromatography were predicted using a two-parameter model, on the basis of thermodynamic data obtained from isothermal runs on seven capillary columns, primarily substituted with 5% diphenylsiloxane. The scope for using thermodynamic data obtained from isothermal runs on one column to optimize separation on a different column or a different instrument setup was investigated. Additionally, the predictive utility of thermodynamic data obtained using a DB-5 column that had been in use for three years was compared to that of a new column of the same model. It was found that satisfactory separation could be achieved on one capillary column or instrument setup on the basis of thermodynamic data obtained using a different column or instrument set-up.

  Read more about Comparing columns for gas chromatography with the two-parameter model for retention prediction

Show all publications by Ioannis Sadiktsis at Stockholm University