C. Vanhoof - Academia.edu (original) (raw)

Papers by C. Vanhoof

J. Anal. At. Spectrom., 2015

Inorganic arsenic species in ambient particulate matter (PM 10 and PM 2.5 ) have been determined ... more Inorganic arsenic species in ambient particulate matter (PM 10 and PM 2.5 ) have been determined in an urban area, in the vicinity of a metallurgical industrial plant. The developed high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC/ICP-MS) method allows monitoring of particulate As(III) and As(V)-species, with a limit of quantification of 0.34 ng m À3 As(III) and 0.23 ng m À3 As(V), respectively. Good agreement was obtained between the sum of the concentrations of As(III) and As(V) determined by HPLC/ICP-MS and the total As concentrations determined by XRF, indicating a complete extraction of the As species. During the measuring campaigns for PM 10 and PM 2.5 , a significant conversion (oxidation) up to 54% of exogenous spiked As(III) was observed. The total amount of the spiked As(III) was well-recovered (PM 10 and PM 2.5 on average 108% and 101%, respectively). The extraction of the filter in combination with the sampled air matrix is likely to induce the As(III) conversion. The average measured As concentration in PM 10 during a 40-day monitoring campaign (30 ng m À3 ) at a hot spot location is above the European target value of 6 ng m À3 . The measured As concentration in PM 2.5 was half the value of the measured concentration in PM 10 and no relative enrichment of total As was observed in either particulate matter fractions. However, in PM 10 , As(V) was the main component, while in PM 2.5 , As(III) was the dominant species. During the monitoring campaign, the fraction of particulate As(III) varied between 19 and 61% in PM 10 and a trend towards a higher fraction of As(III) with increasing concentration of total As was observed. XANES and XRD analyses were used for the identification of arsenic species in local PM sources and confirmed the presence of Ca 3 Sr 2 (AsO 4 ) 2.5 (PO 4 ) 0.5 (OH), As 2 O 3 and As 2 O 5 species.

A fast and reliable method for the analysis of airborne loaded filters becomes more and more impo... more A fast and reliable method for the analysis of airborne loaded filters becomes more and more important for monitoring campaigns and inventory studies at sites with airborne pollution. X- ray fluorescence spectroscopy (XRF) can perform quantitative analysis on filters without any pretreatment. Quantitative determination of various metals on loaded filters requires the use of calibration curves set up with synthetic filters. For accurate analysis, the calibration standards have to be prepared with a comparable matrix composition as the real filter samples. Therefore, cellulose nitrate filters were loaded by means of aerosol generation with various metals. The performance of an optimized aerosol generation system, based on the ultrasonic nebulization of a multi-element solution, is presented in this work. A multi-element solution is converted into a fine dense aerosol by ultrasonic action. The produced aerosol is dried and collected onto a filter. Filters can be loaded sequentially wit...

Spectrochimica Acta Part B: Atomic Spectroscopy, 2014

ABSTRACT As the ratio of phosphorus and sulfur in proteins allows the determination of the phosph... more ABSTRACT As the ratio of phosphorus and sulfur in proteins allows the determination of the phosphorylation degree in proteins, the absolute determination of phosphorus and sulfur in organic samples is of growing interest. While it takes some effort to quantify phosphorus and sulfur with Inductively Coupled Quadrupole Plasma Mass Spectrometry (ICP-QMS), Total reflection X-Ray Fluorescence Analysis (TXRF) allows easy quantification. In the presented work the low Z TXRF spectrometer at Atominstitut was used to analyze phosphorus and sulfur in proteins. Although the preparation of the protein samples proved to be more difficult than originally expected, it could be shown that TXRF is well suited for the determination of P and S in proteins. The obtained lower limits of detection (LLD) for P and S in proteins were extrapolated for 1000s and were 34 pg and 19 pg, respectively. The importance of height scans for each sample to exclude heterogeneities was demonstrated.

X-Ray Spectrometry, 2003

A risk assessment study of the air quality in the surrounding of roads covered with slags coming ... more A risk assessment study of the air quality in the surrounding of roads covered with slags coming from the non-ferrous metal industry was performed. A monitoring campaign was carried out at three locations in Flanders by collecting the PM10 fraction and the total suspended particulates (TSP) of the airborne dust particles, entrapping heavy metals, on membrane filters. The heavy metal concentration on the dust filters was determined by wavelength-dispersive x-ray fluorescence (WD-XRF) spectrometry. The XRF calibration curves were set up with filter standards prepared in the laboratory using an aerosol-generated loading system. The acquired WD-XRF results were confirmed by inductively coupled plasma atomic emission spectrometric (ICP-AES) measurements after acid digestion on a selected number of filters. Electron probe microanalysis (EPMA) confirmed that aerosol-loaded filter standards and dust filters with a concentration level of the analyzed element below 3300 ng cm −2 were homogeneously distributed. Dust filters with higher concentrations, and especially filters loaded with the TSP fraction, reflected an inhomogeneous distribution of the analyzed element on the filter. The WD-XRF analytical results acquired in the monitoring campaign revealed that the concentration of Pb on the dust filters never exceeded the immission standard (yearly average) of 2000 ng m −3 . It can be stated that the impact on human health is limited and can still be reduced by covering the polluted roads with a layer of asphalt. Further evaluation of soil and water samples from the nearby surroundings reveals that the heavy metal content in the slags makes an important contribution to environmental pollution, especially the contamination of groundwater.

Journal of Porous Materials, 1996

ABSTRACT

Journal of Environmental Monitoring, 2004

To determine the heavy metal content in soil samples at contaminated locations, a static and time... more To determine the heavy metal content in soil samples at contaminated locations, a static and time consuming procedure is used in most cases. Soil samples are collected and analyzed in the laboratory at high quality and high analytical costs. The demand by government and consultants for a more dynamic approach and by customers requiring performances in which analyses are performed in the field with immediate feedback of the analytical results, is growing. Especially during the follow-up of remediation projects or during the determination of the sampling strategy, field analyses are advisable. For this purpose four types of ED-XRF systems, ranging from portable up to high performance laboratory systems, have been evaluated. The evaluation criteria are based on the performance characteristics for all the ED-XRF systems such as limit of detection, accuracy and the measurement uncertainty on one hand, and also the influence of the sample pretreatment on the obtained results on the other hand. The study proved that the field portable system and the bench top system, placed in a mobile van, can be applied as field techniques, resulting in semi-quantitative analytical results. A limited homogenization of the analyzed sample significantly increases the representativeness of the soil sample. The ED-XRF systems can be differentiated by their limits of detection which are a factor of 10 to 20 higher for the portable system. The accuracy of the results and the measurement uncertainty also improved using the bench top system. Therefore, the selection criteria for applicability of both field systems are based on the required detection level and also the required accuracy of the results.

Journal of Analytical Atomic Spectrometry, 2011

Nickel speciation and fractionation using a multidisciplinary approach are discussed for differen... more Nickel speciation and fractionation using a multidisciplinary approach are discussed for different particulate matter samples collected in industrial and rural atmospheres. The technologies utilized in this research span from X-ray Absorption Near Edge Structure (XANES) and X-Ray Diffraction (XRD) to a wet chemistry sequential leaching assay (including determination by inductively coupled plasma atomic emission spectroscopy, ICP-AES). The Zatka sequential leaching method provides an inexpensive assay to differentiate among 'soluble', 'sulfidic', 'metallic', and 'oxidic' chemical forms of Ni. The XANES technique is especially well suited for Ni speciation between and to a lesser extent within the 4 defined Ni species groups of the Zatka sequential leaching procedure. Limitations for interpretation in the present study with respect to XANES are the availability of pure phase Ni species for uptake as reference spectra and the collinearity between the spectra of Ni compounds within a Ni species group (e.g. NiSO 4 6H2OandNi(NO3)26H 2 O and Ni(NO 3 ) 2 6H2OandNi(NO3)26H 2 O). The Ni speciation and fractionation results on the particulate matter samples reflect in general a good agreement between the modified Zatka sequential leaching procedure and the XANES data. For the particulate matter collected in and close to a stainless steel factory, Ni included in a spinel structure (NiFe 2 O 4 ) was identified as the principal Ni species. The particulate matter collected in rural atmosphere showed a 50/50 distribution between soluble and oxidic Ni species.

Journal of Analytical Atomic Spectrometry, 2011

X-Ray Spectrometry, 2013

ABSTRACT In consequence of several European Union Directives, there is an increasing need for rap... more ABSTRACT In consequence of several European Union Directives, there is an increasing need for rapid and easy-to-handle screening tools to identify hazardous substances or to verify the absence of those substances. A field trial was executed to evaluate the capability of portable/handheld X-ray fluorescence (XRF) systems for screening waste loads on hazardous substances as incoming inspection at waste handling plants to characterise the waste material or to classify it by its key variables (critical parameters). For the field trial, six different waste materials were prepared: construction waste, shredder material, contaminated soil, waste wood, Pb granulate and slag from a municipal incineration waste. In total, eight different XRF instruments were evaluated. The results indicate that for screening analysis, the pretreatment of the sample is of minor relevance. Additionally, the results prove that the degree of homogeneity/heterogeneity of the material strongly influences the dispersion of the results of repeated measurements. The obtained results proved that for specific samples (e.g. organic matrices, elevated contaminant concentrations and high water content), an appropriate adjustment of the matrix effects and spectral overlap corrections are required to improve the quality of the XRF results. In the overall assessment, this analytical method can be recommended as a screening method for the analysis of waste, as more than 80% of the obtained results were situated within a predefined range of accuracy. Handheld XRF analysers are the detection method of choice for the initial analysis of elements in waste, as this method is fast, reliable, handy and cost-effective and allows easy checking of sample heterogeneity.

J. Anal. At. Spectrom., 2015

Inorganic arsenic species in ambient particulate matter (PM 10 and PM 2.5 ) have been determined ... more Inorganic arsenic species in ambient particulate matter (PM 10 and PM 2.5 ) have been determined in an urban area, in the vicinity of a metallurgical industrial plant. The developed high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC/ICP-MS) method allows monitoring of particulate As(III) and As(V)-species, with a limit of quantification of 0.34 ng m À3 As(III) and 0.23 ng m À3 As(V), respectively. Good agreement was obtained between the sum of the concentrations of As(III) and As(V) determined by HPLC/ICP-MS and the total As concentrations determined by XRF, indicating a complete extraction of the As species. During the measuring campaigns for PM 10 and PM 2.5 , a significant conversion (oxidation) up to 54% of exogenous spiked As(III) was observed. The total amount of the spiked As(III) was well-recovered (PM 10 and PM 2.5 on average 108% and 101%, respectively). The extraction of the filter in combination with the sampled air matrix is likely to induce the As(III) conversion. The average measured As concentration in PM 10 during a 40-day monitoring campaign (30 ng m À3 ) at a hot spot location is above the European target value of 6 ng m À3 . The measured As concentration in PM 2.5 was half the value of the measured concentration in PM 10 and no relative enrichment of total As was observed in either particulate matter fractions. However, in PM 10 , As(V) was the main component, while in PM 2.5 , As(III) was the dominant species. During the monitoring campaign, the fraction of particulate As(III) varied between 19 and 61% in PM 10 and a trend towards a higher fraction of As(III) with increasing concentration of total As was observed. XANES and XRD analyses were used for the identification of arsenic species in local PM sources and confirmed the presence of Ca 3 Sr 2 (AsO 4 ) 2.5 (PO 4 ) 0.5 (OH), As 2 O 3 and As 2 O 5 species.

A fast and reliable method for the analysis of airborne loaded filters becomes more and more impo... more A fast and reliable method for the analysis of airborne loaded filters becomes more and more important for monitoring campaigns and inventory studies at sites with airborne pollution. X- ray fluorescence spectroscopy (XRF) can perform quantitative analysis on filters without any pretreatment. Quantitative determination of various metals on loaded filters requires the use of calibration curves set up with synthetic filters. For accurate analysis, the calibration standards have to be prepared with a comparable matrix composition as the real filter samples. Therefore, cellulose nitrate filters were loaded by means of aerosol generation with various metals. The performance of an optimized aerosol generation system, based on the ultrasonic nebulization of a multi-element solution, is presented in this work. A multi-element solution is converted into a fine dense aerosol by ultrasonic action. The produced aerosol is dried and collected onto a filter. Filters can be loaded sequentially wit...

Spectrochimica Acta Part B: Atomic Spectroscopy, 2014

ABSTRACT As the ratio of phosphorus and sulfur in proteins allows the determination of the phosph... more ABSTRACT As the ratio of phosphorus and sulfur in proteins allows the determination of the phosphorylation degree in proteins, the absolute determination of phosphorus and sulfur in organic samples is of growing interest. While it takes some effort to quantify phosphorus and sulfur with Inductively Coupled Quadrupole Plasma Mass Spectrometry (ICP-QMS), Total reflection X-Ray Fluorescence Analysis (TXRF) allows easy quantification. In the presented work the low Z TXRF spectrometer at Atominstitut was used to analyze phosphorus and sulfur in proteins. Although the preparation of the protein samples proved to be more difficult than originally expected, it could be shown that TXRF is well suited for the determination of P and S in proteins. The obtained lower limits of detection (LLD) for P and S in proteins were extrapolated for 1000s and were 34 pg and 19 pg, respectively. The importance of height scans for each sample to exclude heterogeneities was demonstrated.

X-Ray Spectrometry, 2003

A risk assessment study of the air quality in the surrounding of roads covered with slags coming ... more A risk assessment study of the air quality in the surrounding of roads covered with slags coming from the non-ferrous metal industry was performed. A monitoring campaign was carried out at three locations in Flanders by collecting the PM10 fraction and the total suspended particulates (TSP) of the airborne dust particles, entrapping heavy metals, on membrane filters. The heavy metal concentration on the dust filters was determined by wavelength-dispersive x-ray fluorescence (WD-XRF) spectrometry. The XRF calibration curves were set up with filter standards prepared in the laboratory using an aerosol-generated loading system. The acquired WD-XRF results were confirmed by inductively coupled plasma atomic emission spectrometric (ICP-AES) measurements after acid digestion on a selected number of filters. Electron probe microanalysis (EPMA) confirmed that aerosol-loaded filter standards and dust filters with a concentration level of the analyzed element below 3300 ng cm −2 were homogeneously distributed. Dust filters with higher concentrations, and especially filters loaded with the TSP fraction, reflected an inhomogeneous distribution of the analyzed element on the filter. The WD-XRF analytical results acquired in the monitoring campaign revealed that the concentration of Pb on the dust filters never exceeded the immission standard (yearly average) of 2000 ng m −3 . It can be stated that the impact on human health is limited and can still be reduced by covering the polluted roads with a layer of asphalt. Further evaluation of soil and water samples from the nearby surroundings reveals that the heavy metal content in the slags makes an important contribution to environmental pollution, especially the contamination of groundwater.

Journal of Porous Materials, 1996

ABSTRACT

Journal of Environmental Monitoring, 2004

To determine the heavy metal content in soil samples at contaminated locations, a static and time... more To determine the heavy metal content in soil samples at contaminated locations, a static and time consuming procedure is used in most cases. Soil samples are collected and analyzed in the laboratory at high quality and high analytical costs. The demand by government and consultants for a more dynamic approach and by customers requiring performances in which analyses are performed in the field with immediate feedback of the analytical results, is growing. Especially during the follow-up of remediation projects or during the determination of the sampling strategy, field analyses are advisable. For this purpose four types of ED-XRF systems, ranging from portable up to high performance laboratory systems, have been evaluated. The evaluation criteria are based on the performance characteristics for all the ED-XRF systems such as limit of detection, accuracy and the measurement uncertainty on one hand, and also the influence of the sample pretreatment on the obtained results on the other hand. The study proved that the field portable system and the bench top system, placed in a mobile van, can be applied as field techniques, resulting in semi-quantitative analytical results. A limited homogenization of the analyzed sample significantly increases the representativeness of the soil sample. The ED-XRF systems can be differentiated by their limits of detection which are a factor of 10 to 20 higher for the portable system. The accuracy of the results and the measurement uncertainty also improved using the bench top system. Therefore, the selection criteria for applicability of both field systems are based on the required detection level and also the required accuracy of the results.

Journal of Analytical Atomic Spectrometry, 2011

Nickel speciation and fractionation using a multidisciplinary approach are discussed for differen... more Nickel speciation and fractionation using a multidisciplinary approach are discussed for different particulate matter samples collected in industrial and rural atmospheres. The technologies utilized in this research span from X-ray Absorption Near Edge Structure (XANES) and X-Ray Diffraction (XRD) to a wet chemistry sequential leaching assay (including determination by inductively coupled plasma atomic emission spectroscopy, ICP-AES). The Zatka sequential leaching method provides an inexpensive assay to differentiate among 'soluble', 'sulfidic', 'metallic', and 'oxidic' chemical forms of Ni. The XANES technique is especially well suited for Ni speciation between and to a lesser extent within the 4 defined Ni species groups of the Zatka sequential leaching procedure. Limitations for interpretation in the present study with respect to XANES are the availability of pure phase Ni species for uptake as reference spectra and the collinearity between the spectra of Ni compounds within a Ni species group (e.g. NiSO 4 6H2OandNi(NO3)26H 2 O and Ni(NO 3 ) 2 6H2OandNi(NO3)26H 2 O). The Ni speciation and fractionation results on the particulate matter samples reflect in general a good agreement between the modified Zatka sequential leaching procedure and the XANES data. For the particulate matter collected in and close to a stainless steel factory, Ni included in a spinel structure (NiFe 2 O 4 ) was identified as the principal Ni species. The particulate matter collected in rural atmosphere showed a 50/50 distribution between soluble and oxidic Ni species.

Journal of Analytical Atomic Spectrometry, 2011

X-Ray Spectrometry, 2013

ABSTRACT In consequence of several European Union Directives, there is an increasing need for rap... more ABSTRACT In consequence of several European Union Directives, there is an increasing need for rapid and easy-to-handle screening tools to identify hazardous substances or to verify the absence of those substances. A field trial was executed to evaluate the capability of portable/handheld X-ray fluorescence (XRF) systems for screening waste loads on hazardous substances as incoming inspection at waste handling plants to characterise the waste material or to classify it by its key variables (critical parameters). For the field trial, six different waste materials were prepared: construction waste, shredder material, contaminated soil, waste wood, Pb granulate and slag from a municipal incineration waste. In total, eight different XRF instruments were evaluated. The results indicate that for screening analysis, the pretreatment of the sample is of minor relevance. Additionally, the results prove that the degree of homogeneity/heterogeneity of the material strongly influences the dispersion of the results of repeated measurements. The obtained results proved that for specific samples (e.g. organic matrices, elevated contaminant concentrations and high water content), an appropriate adjustment of the matrix effects and spectral overlap corrections are required to improve the quality of the XRF results. In the overall assessment, this analytical method can be recommended as a screening method for the analysis of waste, as more than 80% of the obtained results were situated within a predefined range of accuracy. Handheld XRF analysers are the detection method of choice for the initial analysis of elements in waste, as this method is fast, reliable, handy and cost-effective and allows easy checking of sample heterogeneity.