Microanalytical concept for multicomponent analysis of airborne particulate matter

Summary A microanalytical concept is presented that permits the determination of four ionic species (NH ₄ ⁺ , Cl^–, NO ₃ ^– , SO ₄ ^2– and 16 elements (Al, As, Cd, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Si, V, Zn) in minute samples of filter collected atmospheric particulate matter. The multistage procedure is based on consecutive aqueous extraction and acid digestion of the entire sample. Ion analysis of the extract is made by flow injection analysis (FIA) and single column ion chromatography (SCIC) with total consumption of only 50 l sample volume. Flame and furnace atomic absorption spectroscopy (AAS) is employed for element analysis after acid decomposition in a closed microwave digestion system. Using flow injection sample introduction for flame-AAS a liquid volume of 2 ml is sufficient for determination of 10 elements. Determination of the remaining 6 elements by graphite furnace AAS requires 1 ml. The quality assurance programme is briefly described. It includes the analysis of standard reference materials, intercomparison with other laboratories and the use of alternative methods for accuracy control.     

Elemental determination of airborne particulate matter by XRF

Multielement determination of airbone particulates collected on PTFE-membrane filters by XRF, and possibility of using this technique in Receptor Model analysis were investigated. In order to keep the background interference as low as possible, special emphasis was therefore laid on the setup of optimized analytical procedures for XRF measurement. An intercomparison between INAA and XRF methods was performed by analyzing the same filter samples.     

Application of receptor models to airborne particulate matter

The human activities in their various aspects cause a change in the natural air quality. This change results more marked in very populated and in high industrialized areas. Some pollutants emitted are typical of a particular activity. Each source of pollution is identified by its profile in the composition of the emissions in the environment. Multivariate receptor models can be used in order to apportion pollutants to the different sources assessing the contribution of each source to the total pollution.This paper deals with the application of Absolute Principal Component Scores (APCS) receptor model to data obtained from the automatic network of air quality monitoring in the city of Bari (South Italy). The parameters monitored by automatic networks, as bihourly values, are PM₁₀, NO_x, CO, Benzene, Toluene, Xilene. The data shown in this paper concerning 1 month almost of sampling in different monitoring stations of Bari Municipality during the period of time from January 2005 to April 2006. Moreover preliminary results obtained applying the APCS model to daily PM_2.5 samples collected during SITECOS PRIN project are shown. The results concerning data collected in corso Cavour (Bari) during the month of October 2005.The results obtained by APCS receptor model seem to suggest a poor contribution of the “vehicular traffic source” and a relevant contribution of the “secondary particulate source” to particulate matter concentrations.     

Intercomparison of IAEA airborne particulate matter reference material

Fifty air filters with fine and coarse fractions were prepared from NIST 2710 contaminated soil. Eighteen pairs were made and sent to laboratories of the Coordinated Research Program (CRP) on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques for elemental determination. The results of this intercomparison are discussed in this paper.     

Analytical methods for assessing metal bioaccessibility in airborne particulate matter: A scoping review

In contrast to the existence of standardized methods to assess metal bioaccessibility via the gastrointestinal route, there are no widely-accepted, established in vitro testing protocols to measure elemental solubility in the human lung. This may be attributed, in part, to the difficulty associated with simulating the lung’s complex in vivo conditions. The purpose of this review is two-fold: (1) to determine how the bioaccessibility of metals associated with ambient particulate matter (PM) in the human lung has been assessed in the literature, and (2) examine the suitability and biological relevance of applied methods for the measurement of metal bioaccessibility employed to date.     

Remarks on the detection of phenols in airborne particulate matter

Summary Samples of suspended particulate matter collected in Duisburg were investigated for phenolic compounds. The loaded filters were extracted with dichloromethane for 10 hours in a soxhlet apparatus. The concentrated extract was resolved in cyclohexane and separated into a non polar and a polar fraction on alumina. The polar fraction was taken up in dichloromethane and steam-distilled. The distillate was extracted with ether. After the evaporation of the ether, the residue was resolved in dichloromethane and allowed to react with benzoyl chloride. After adding toluene the solution was reduced in volume and analyzed in a GC-MS system. For the separation of phenols by means of HPLC the enrichment of the phenols was performed without benzoylization. Six phenols were detected: hydroxibenzene, methylhydroxibenzene, hydroxibiphenyl, hydroxifluorene, benzylhydroxibenzene and dihydroxibiphenyl.     

Comparison of extracting solutions for elemental fractionation in airborne particulate matter

It is here described the comparison of extraction efficiency of some solutions (acetate buffer, deionized water, diluted HNO₃ and EDTA) frequently adopted in literature for evaluating the elemental solubility in airborne particulate matter. This comparison was performed considering the distribution of As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, S, Si, Sb, Sn, Sr, Ti, V, Zn between the extractable and mineralized residual fractions on the NIST 1648 certified material, PM₁₀ real samples and size-segregated samples, collected by a 13-stage impactor.The extracting solutions were evaluated by comparing extractive efficiencies and robustness towards some factors, such as acidity and concentration of complexing species, that have great environmental variability and that could be able to modify the extractive efficiency.Furthermore, extraction methods application to size-segregated samples allowed estimating the selectivity of extracting solutions towards dimensionally characterized emission sources, as dusts originated from abrasion and road dust re-suspension.On the basis of the obtained results, it was possible to define the main advantages and disadvantages resulting from the use of different extracting solutions, necessary to make possible the comparison of environmental studies carried out in different extractive conditions and to start up a proper study for harmonizing extracting procedures.     

A new approach for determination of crustal and trace elements in airborne particulate matter

An ICP-OES procedure was developed for fast and accurate determination of various crustal (Al, Ca, Fe, Mg, Si) and trace elements (Ba, Cu, Mn, Na, K, Sr, Ti, Zn) in airborne particulate matter. The method is based on a preliminary treatment of the aerosol samples with a mixture of nitric acid and hydrogen peroxide at elevated temperature leading to a mineralization of the organic sampling substrate, dissolution of soluble material and homogeneous suspension of the remaining non-soluble fraction. After dilution the derived slurry solutions were measured using ICP-OES. The reproducibility of analysis given as the relative standard deviation (% RSD) varied between 3.2 and 6.8% for bulk constituents such as Al, Ca, Fe, Mg and Si whereas values ranging from 3.5 to 9.1% were obtained for trace metals present with distinctly lower abundance in PM10 (e.g. Ba, Cu, Mn, Sr, Zn). The limits of detection (LOD) calculated as three times the standard deviation (3σ) of the signal derived from filter blank samples ranged from approximately 1?ng?m^?3 (Sr) to 71?ng?m^?3(Ca). The developed procedure was evaluated by comparing the obtained results with the findings derived for the same set of aerosol samples analyzed using a microwave procedure for sample dissolution with subsequent ICP-OES analysis. Finally the developed procedure was applied for the analysis of crustal and trace elements in PM10 samples collected at an urban site (Getreidemarkt, Vienna) and a rural site (Hartberg, Styria), in Austria. The concentrations of the investigated crustal elements varied between some hundred ng?m^?3 and few µg?m^?3 with highest concentrations for Fe and Si, distinctly reduced concentrations ranging from some ng?m^?3 (Sr) to more than hundred ng?m^?3 (K) were found for trace elements. Observed PM10 concentrations were found to be in accordance to literature findings from urban sites in central Europe.     

Rapid extraction of water soluble organic compounds from airborne particulate matter.

Water soluble organic compounds (WSOC) in airborne particulate matter (PM) have received considerable attention in recent years due to their abundance and their importance in atmospheric processes. The analysis of WSOC is necessary for quantifying the relative contribution of individual organic compounds to the total WSOC mass. In the present work, we evaluated the performance of a microwave-assisted extraction (MAE) method for the determination of WSOC in PM and compared the data with those of a conventional ultrasonic extraction (USE). The experimental results showed that the MAE method requires a shorter extraction time (5 min) compared to USE. The isolated water-soluble organic fraction of PM was subsequently analyzed using ion chromatography (IC) for low molecular weight organic acids. The rapid MAE method was used in conjunction with IC for the analysis of organic acids in PM samples, collected from different sources.     

Energy dispersive X-ray fluorescence analysis of airborne particulate matter

Positron annihilation lifetime technique was applied to study the electric field dependence of size, intensity and size distribution of free volumes in various liquid crystals negative nematic MBBA(N-(4-methoxybenzylidene)-4-n-butylaniline), positive nematic 5CB (4-cyano-4-n-pentylbiphenyl) and cholesteric mixture of MBBA and cholesteryl oleate. Positron annihilation decay curves were obtained in the direct and alternate electric field range from 0 to 120 V/mm, and annihilation curves were resolved into four lifetime components. The relation between the free volume parameters and the variation of molecular alignment is discussed for nematic and cholesteric liquid crystals.     

Quality control materials for the determination of trace elements in airborne particulate matter

The development of quality control materials for the determination of selected trace elements in air pollution studies is described. Three types of test samples were prepared for proficiency testing: (1) filters loaded with PM10 fraction of urban air particulate matter (APM) using high-volume air samplers, which were subsequently divided into smaller sections, (2) a bulk sample of APM collected in an automobile tunnel in Prague, and (3) simulated air filters loaded with APM using a wet deposition process. Homogeneity of the test samples was studied using instrumental neutron activation analysis, proton induced X-ray emission and atomic absorption spectrometry, and inductively coupled plasma optical emission spectrometry and mass spectrometry. Sufficiently homogeneous samples were prepared by all three procedures. The simulated air filters appeared to be the most suitable test samples for proficiency testing.     

Direct ultrasonic agitation for rapid extraction of organic matter from airborne particulate

Direct ultrasonic extraction (DUE) is proposed as simple and rapid sample pretreatment method. This new approach is applied to the extraction of particulate organic matter (POM) from airborne particulate by using dichloromethane (DCM) or DCM/methanol (90/10, v/v) as extractant. The analytical determination was carried out by weighing the extractable POM on an electrobalance. Total recovery for POM could be obtained when the sample was extracted three times with 25-50 mL extractant each for about 5 min at 50 W ultrasonic power. In comparison with conventional Soxhlet extraction, less extraction time (total 15 min only) and solvent consumption (100 mL) were required by DUE. The efficiency of the DUE was similar or even higher than the routine Soxhlet method. Additionally, the new extractor is very simple and easy to use and can accelerate the extraction procedures of organic components from various solid samples.     

Direct ultrasonic agitation for rapid extraction of organic matter from airborne particulate

Direct ultrasonic extraction (DUE) is proposed as simple and rapid sample pretreatment method. This new approach is applied to the extraction of particulate organic matter (POM) from airborne particulate by using dichloromethane (DCM) or DCM/methanol (90/10, v/v) as extractant. The analytical determination was carried out by weighing the extractable POM on an electrobalance. Total recovery for POM could be obtained when the sample was extracted three times with 25–50 mL extractant each for about 5 min at 50 W ultrasonic power. In comparison with conventional Soxhlet extraction, less extraction time (total 15 min only) and solvent consumption(100 mL) were required by DUE. The efficiency of the DUE was similar or even higher than the routine Soxhlet method. Additionally, the new extractor is very simple and easy to use and can accelerate the extraction procedures of organic components from various solid samples.     

Neutron activation analysis of platinum metals in airborne particulate matter

A method is described for the determination of Au, Pt, Pd, Ag and Ir in two atmospheric aerosol samples, namely in Ghent and in the Milanese intercomparison sample. After neutron irradiation the samples are fused with Na₂O₂. Gold is extracted with ethylacetate, Pt precipitated as (NH₄)₂PtCl₆ Pd as dimethylglyoximate, Ag as chloride and Ir separated by anion-exchange adsorption and batch extraction. Ge(Li) gamma-spectrometry is applied for all determinations. The concentrations in ng·g⁻¹ in the samples are respectively: Au: 49 and 3000; Pt: below 100 for both samples; Pd: 7 and 28; Ag: 6000 and 14 000; Ir: 2.5 and 1.3.     

Quality assessment on airborne particulate matter of k0-INAA

The analysis of airborne particulate matter (APM) by k ₀-NAA was assessed using: (1) BCR reference material (RM) simulated air-filters, (2) synthetic air-filters prepared by spiking blank filters with standard solutions, and (3) real APM filters. k ₀-INAA is a suitable technique for the analysis of APM, delivering accurate and precise results. However, the quality assessment of APM analysis appears to be a difficult task.     

INAA for the characterization of airborne particulate matter from the industrial area of Islamabad city

Air particulate matter (PM) was collected in two size fractions using stacked filter units (SFUs) provided by the International Atomic Energy Agency (IAEA) from the industrial area of Islamabad. Nucleopore polycarbonate filters were used for collecting from Oct 98 to Jun 99 the particulate matter in coarse and fine size fractions. The samples were characterized by the instrumental neutron activation analysis (INAA). About 33 elements were quantified using different irradiation and counting protocols.     

Metrological traceability for benzo[a]pyrene quantification in airborne particulate matter

Airborne particulate matter (PM) represents one of the most important sources of urban pollution due to its physical and chemical properties. There is a great concern for PM dangerous effects on human health because particles can deeply penetrate into the respiratory system, carrying the contaminants adsorbed onto their surface. Polycyclic aromatic hydrocarbons (PAHs) are a class of organic contaminants that can be adsorbed onto PM and can have harmful effects on health, due to their particular chemical structure. The International Agency for Research on Cancer (IARC) classified PAHs as potential carcinogenic agents and benzo[a]pyrene (BaP) as carcinogenic to humans. In this paper, the development of a metrologically traceable procedure for the quantification of BaP in airborne PM, performed at the Italian National Institute of Metrological Research (Istituto Nazionale di Ricerca Metrologica—I.N.Ri.M.), is presented. The identification and quantification of BaP in PM samples were carried out by gas chromatography coupled with mass spectrometry (GC–MS). Metrological traceability was established in all the procedure steps, after performing the method validation. Suitable certified reference materials (CRMs) were used both to validate the analytical method and to calibrate the GC–MS. The measurement uncertainty was evaluated by identifying and taking into account all the relevant sources deriving from the whole procedure steps.     

Determination of palladium in airborne particulate matter in a German city

The part of palladium in ambient urban air that is bound to particles and soluble in aqua regia was determined by means of sorbent extraction, coupled with graphite furnace atomic absorption spectrometry (GFAAS) and laser absorption fluorescence spectrometry (LAFS). Samples of about 200 m³ air were taken in a suburb of Berlin, Germany. The coupling of the selective and automated pre-concentration procedure for Pd as N,N-diethyl-N’-benzoylthiourea complex with the respective detection methods proved to be sufficiently sensitive. Severe interference with other matrix constituents, occurring mainly by direct LAFS detection, could be overcome and the detection limit was improved tremendously. The concentration of Pd in ambient air was determined to be in the range from 0.2 to 14.6 pg/m³.