Comparison of multiple X-ray fluorescence techniques for elemental analysis of particulate matter collected on air filters (original) (raw)
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Talanta, 2011
Total Reflection X-ray Fluorescence (TXRF) is a well-established technique for chemical analysis, but it is mainly employed for quality control in the electronics semiconductor industry. The capability to analyze liquid and uniformly thin solid samples makes this technique suitable for other applications, and especially in the very critical field of environmental analysis. Comparison with standard methods like inductively coupled plasma (ICP) and atomic absorption spectroscopy (AAS) shows that TXRF is a practical, accurate, and reliable technique in occupational settings. Due to the greater sensitivity necessary in trace heavy metal detection, TXRF is also suitable for environmental chemical analysis. In this paper we show that based on appropriate standards, TXRF can be considered for non-destructive routine quantitative analysis of environmental matrices such as air filters. This work has been developed in the frame of the EU-FP6 PHIME (Public Health Impact of long-term, low-level Mixed element Exposure in susceptible population strata) Integrated Project (www.phime.org). The aim of this work was to investigate Mn air pollution in the area of Vallecamonica (Italy).
This work is presented as an improvement of a recently introduced method for airborne particulate matter (PM) filter analysis [1]. X-ray standing wave (XSW) and total reflection X-ray fluorescence (TXRF) were performed with a new dedicated laboratory instrumentation. The main advantage of performing both XSW and TXRF, is the possibility to distinguish the nature of the sample: if it is a small droplet dry residue, a thin film like or a bulk sample. Another advantage is related to the possibility to select the angle of total reflection to make TXRF measurements. Finally, the possibility to switch the X-ray source allows to measure with more accuracy lighter and heavier elements (with a change in X-ray anode, for example from Mo to Cu). The aim of the present study is to lay the theoretical foundation of the new proposed method for airborne PM filters quantitative analysis improving the accuracy and efficiency of quantification by means of an external standard. The theoretical model presented and discussed demonstrated that airborne PM filters can be considered as thin layers. A set of reference samples is prepared in laboratory and used to obtain a calibration curve. Our results demonstrate that the proposed method for quantitative analysis of air PM filters is affordable and reliable without the necessity to digest filters to obtain quantitative chemical analysis, and that the use of XSW improve the accuracy of TXRF analysis.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
Within the framework of research projects focusing on the sampling and analysis of airborne particulate matter, Particle Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (ED-XRF) techniques are routinely used in many laboratories throughout the world to determine the elemental concentration of the particulate matter samples. In this work an inter-laboratory comparison of the results obtained from analysing several samples (collected on both Teflon and quartz fibre filters) using both techniques is presented. The samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of INFN-LABEC laboratory) and by XRF (in Elche, using the ARL Quant'X EDXRF spectrometer with specific conditions optimized for specific groups of elements). The results from the two sets of measurements are in good agreement for all the analysed samples, thus validating the use of the ARL Quant'X EDXRF spectrometer and the selected measurement protocol for the analysis of aerosol samples. Moreover, thanks to the comparison of PIXE and XRF results on Teflon and quartz fibre filters, possible self-absorption effects due to the penetration of the aerosol particles inside the quartz fibre-filters were quantified.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2020
This paper presents the assessment of a direct method to measure and analyse Pb in air particulate matter (PM) collected on polytetrafluoroethylene (PTFE) filtering membranes prepared by the SMART STORE® procedure. The suitability of grazing incidence X-ray fluorescence technique is verified on a set of continuous and conformal thin film samples created by atomic layer deposition. Different scans changing the angles of incidence are performed and the fluorescence intensity of thin films on PTFE substrate compared with that obtained by similar thin films deposited on Si wafer substrates. The effects of sample preparation, constraints, and limitations of the experimental setup are discussed. The results obtained by three commercial total reflection X-ray fluorescence spectrometers, equipped with Mo or Rh X-ray tubes, are compared. Reference samples with different Pb content are used to define the best measurement conditions, corresponding to the maximum fluorescence intensity. The precision is evaluated in terms of relative standard deviation of the net intensity, taking into account the homogeneity of the PM samples and hardware contributions to the errors. The calibration curves are built on the basis of mono-and multi-elemental Pb loaded PTFE reference samples. The analytical parameters, namely linear calibration and determination range, limits of detection, and quantification, are determined.
Journal of Environmental Monitoring, 2007
This paper concludes a five year program on research into the use of a portable X ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively coupled plasma optical emission spectroscopy (ICP OES). The filter samples were collected using different filter holders or ''samplers'' where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported elsewhere. The results, based on data from the three workplaces where lead was the major element present in the samples, are summarized here. A limit of detection and a limit of quantitation are provided. Analysis of some samples using a second analyzer with a different X ray source technology indicated reasonable agreement for some metals (but this was not evaluated for lead). Provided it is only necessary to analyze the filters, most personal samplers will provide acceptable results when used with portable XRF analysis for lead around applicable limit values.
Atmospheric Environment (1967), 1989
Aircraft sampling of atmospheric particulate matter often implies small mass collection for subsequent analysis, especially when free tropospheric samples are considered. We present here results of the use of an X-ray fluorescence instrument, specifically designed for small-mass samples, in the determination of free tropospheric and boundary layer elemental concentrations. Based on l-to 2-h-long samples, ngmV3 ambient air concentrations of Ti, Cr, Mn, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, MO, Cd and Pb may be determined with uncertainties of 5-15% in polluted and even some rural boundary layer samples. In free tropospheric and remote boundary layer samples, concentrations may be determined for many of these elements but with larger uncertainties.
Journal of Applied Sciences and Environmental Management, 2015
assessment of the air quality in Newcastle upon Tyne, UK was performed by determining the trace element content in airborne particulates (PM 10). Samples were collected over a 12 month period (March 2011 to April 2012) using two high volume air sampler provided with a PM 10 size selective inlet. The concentrations of 6 elements (Cr, Cu, Mn, Ni, Pb and Zn) were determined. The mean concentrations of these elements varied widely across the elements with Zn showing the highest concentration (41.3 ± 42.8 ng/m 3 ; ranging from 9.9-209.0 ng/m 3) and Cr the least concentration (1.7 ± 0.9 ng/m 3 ; ranging from 0.4-3.2 ng/m 3). The total elemental content obtained in this work was compared with regulatory limit values for 4 of the elements determined and it was discovered that none exceeded the limit values. © JASEM
Elemental analysis of airborne particulate matter by ED-XRF within the …
Ten residences in El Paso, TX were monitored in the summer of 2001 for concurrent indoor and outdoor PM 2.5 and PM 10 10-min mass concentrations in an attempt to establish the indoor-outdoor PM correlation for typical west Texas residences equipped with evaporative coolers. Simultaneously, the modified tapered element oscillating microbalance instruments were used to collect 48-h PM 2.5 and PM 10 samples, both indoor and outdoor, for elemental analysis. Water samples were also taken at each home for chemical and PM correlation analysis. The air and water samples were analyzed by inductively coupled plasma-mass spectrometry, with 30 elements identifiable above detection limits in the outdoor PM 10 samples and fewer elements in the PM 2.5 and indoor PM 10. Indoor elemental concentrations in PM 10 were found to be approximately 50-70% lower than outdoor concentrations in nine of ten homes, consistent with the PM 10 indoor/outdoor (I/O) mass concentrations previously reported. PM 2.5 I/ O ratio correlations were not as strong as for PM 10 ; however, reduced correlations could be attributed to a pattern of recurring outlier data pairs, consisting of the same three or four elements in all ten homes. Comparison of the elemental concentrations of the evaporative cooler supply water and indoor PM demonstrated little or no correlation, yielding a conclusion that the evaporative cooler was not introducing dissolved solids from the supply water into indoor air. Overall, evaporative cooling appears to provide a cleansing of indoor air.
2009
The unregulated activities of a scrap iron and steel smelting industry in Lagos, Nigeria necessitated the sampling of particulate matter (PM 10 and PM 2.5 ) particles from various sections of the industry. The samples were analyzed using polarized energy dispersive x-ray fluorescence (EDXRF) technique which allowed the simultaneous detection of over 25 elements in each of the samples. The mass concentration levels ranged from 86 to 8765 µg/m 3 for PM 10 and 10 to 462 µg/m 3 for PM 2.5 . The highest concentrations of 8765 and 462 µg/m 3 for PM 10 and PM 2.5 , respectively, were observed at one of the electric arc-furnaces (EAF-2). This was attributed to the scrap smelting and additives used. The observed high concentrations of PM 10 lead (Pb) at various sites, when compared with exposure limit of between 1.0 and 5.0 µg/m 3 set by Occupational safety and Health Administration (OSHA) and United State Environmental Protection Agency (US EPA) is emphasized. For zinc (Zn), the measured levels exceeded the OSHA workplace occupational exposure limit set at 1 mg/m 3 for an 8-h workday over a 40h work week and that set by the National Institute for Occupational Safety and Health (NIOSH) for up to a 10-h workday over 40-h workweek. These results suggest the need for immediate repair or replacement of the emission control devices.
X-Ray Spectrometry, 2013
The aim of this study was to determine and evaluate the temporal profiles of the concentration of chemical elements in the suspended particulate matter present inside a small bronze and an iron foundry industry. To collect the samples, we used a streaker sampler that separates particles with aerodynamic diameters smaller than 10 μm (PM 10) in two fractions: fine (particles with aerodynamic diameters less than 2.5 μm; PM 2.5) and coarse (between 2.5 μm and less than 10 μm; PM 10-2.5). The collection of samples was taken every 20 min during a total time of 8 and 5 h of molding and casting of bronze and iron, respectively. The samples collected in the form of strips on a filter (fine fraction) and an impactor (coarse fraction) were analyzed by the energy dispersive X-ray fluorescence technique. In the excitation, an X-ray tube with Mo target and Zr filter was used, operated at 30 mA/30 kV. For detecting the characteristic of X-rays, a semiconductor Si(Li) detector was used, coupled to a multi-channel spectrometer, with a 300 s excitation/detection time. The results of the temporal profiles of chemical element concentrations in coarse and fine fractions were discussed and compared with the maximum levels set by the Brazilian and international environmental agencies.