Laser-induced breakdown spectroscopy (LIBS) has been in use for decades, but only recently the te... more Laser-induced breakdown spectroscopy (LIBS) has been in use for decades, but only recently the technique has progressed so to allow the construction of efficient handheld, self-contained commercial instruments featuring a large range of capabilities. In particular, the development of portable handheld instruments able to perform non-invasive, spatially resolved, multielement, in-situ analysis has provided an impressive impulse to the scientific investigation of cultural heritage materials. In this work, the design of a handheld LIBS instrument and the first test measurements performed on a fragment of a sedimentary rock monument are presented. A full broadband LIBS emission spectrum with a point and shoot operation was recorded directly within few seconds, so providing information on the elements present in the weathered layer in comparison to the stone surface. Further, the Calibration Free (CF)-LIBS approach was used to test the possibility to obtain a suitable quantitative composition of the main elements present in the sample.
A number of phosphate rocks and organomineral P fertilizers was analyzed comparatively by laser-i... more A number of phosphate rocks and organomineral P fertilizers was analyzed comparatively by laser-induced breakdown spectroscopy (LIBS) in both single-and double-pulse modes associated with two chemometric methods, i.e., principal components analysis (PCA) and partial least squares regression (PLSR). PCA was demonstrated to be a valuable method for the identifi cation of spectral differences between similar samples with only minor compositional differences. The raw and normalized LIBS spectra were able to provide effective identifi cation and discrimination at a 95% confi dence level and in good agreement with the reference concentrations. Results obtained confi rm the promising potential of LIBS for the rapid classifi cation of P fertilizers in situ. Keywords: laser-induced breakdown spectroscopy, phosphate rocks, organomineral fertilizers, principal components analysis, partial least squares regression. Introduction. Optimal fertilizer management is instrumental in obtaining optimized plant productivity and quality by avoiding excessive use that may lead to severe environmental damage such as contamination of surface water and groundwater , especially in areas of intensive crop production, whereas nonoptimal use may cause reduced crop yields. In general, a mineral/inorganic fertilizer is required to guarantee an optimal input of the major nutrients N, P, and K into soil. In contrast, an organomineral fertilizer consists of an appropriate mixture of a mineral rock or an inorganic fertilizer and an organic material generally derived from natural sources such as plant and animal by-products, sewage sludges, municipal biosolid wastes, seaweeds, etc., which can provide a certain amount of major nutrients and organic matter to the soil. In particular, to save the limited primary P reserves available worldwide [1], the use of new P fertilizers consisting of mixtures of organic and secondary mineral P sources available on the market represents a promising alternative. However , correct and effi cient use of organomineral P fertilizers of new generation, i.e., mixtures of phosphate rocks and treated organic wastes, feature a variable composition that requires the development of analytical techniques able to measure and discriminate accurately, rapidly, and cheaply the P content. This will improve their management and effi ciency in agriculture. Laser-induced breakdown spectroscopy (LIBS) is an emerging, rapidly developing and promising analytical technique that can provide real-time, cheap, fast, and easy-to-use multielemental analysis of a variety of materials [2]. LIBS is a minimally destructive method requiring little or no sample pretreatment and no chemicals and produces no disposables. Further, relatively simple, low-cost, compact, and portable instrument confi gurations and packages are available for use outside the laboratory, i.e., on site. Another advantage of LIBS is its suitability for a broad range of multivariate chemometric approaches for data analysis. In the last decades, this technique has been applied in several fi elds [2], including agriculture, e.g., soil, plant, and compost analyses [3–10], but only in the last years has attention been focused on fertilizer analysis [11–16]. The objectives of this work were to evaluate the performance of two LIBS systems associated with two chemometric methods, i.e., principal components analysis (PCA) and partial least squares regression (PLSR), in analyzing comparatively
Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, whic... more Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, which represents one of the world's most relevant carbon reservoirs. In this work, the concentrations of carbon and differences in its composition (humification indexes) were evaluated and compared for several horizons (0 to 390 cm) of three typical Amazonian podzol profiles. Fluorescence spectroscopy was used to investigate the humic acid (HA) fractions of SOM isolated from the different samples. Simple and labile carbon structures appeared to be accumulated in surface horizons, while more complex humified compounds were leached and accumulated in intermediate and deeper Bh horizons. The results suggested that the humic acids originated from lignin and its derivatives, and that lignin could accumulate in some Bh horizons. The HA present in deeper Bh horizons appeared to originate from different formation pathways, since these horizons showed different compositions. There were significant compositional changes of HA with depth, with four types of organic matter: recalcitrant, humified, and old dating; labile and young dating; humified and young dating; and little humified and old dating. Therefore, the humification process had no direct relation with the age of the organic matter in the Amazonian podzols.
A B S T R A C T Laser cleaning is widely used to remove black crusts from weathered limestone mon... more A B S T R A C T Laser cleaning is widely used to remove black crusts from weathered limestone monuments. The cleaning efficiency is commonly tested using conventional analytical techniques, which do not allow to analyze the same sample before and after the treatment. In this paper, micro computed tomography (μ-CT) and micro X-ray fluorescence spectroscopy (μ-XRF) techniques were used for the first time to evaluate the laser cleaning efficiency on two different encrusted quoins collected from a limestone monument. Analyses were carried out non-destructively on the same portion of the two lithotypes before and after the treatment. μ-XRF confirmed the presence of gypsum in the black crust, and showed a marked decrease of S and other typical elements after laser cleaning of both samples. μ-CT clearly showed the different structure of limestone before and after cleaning and the crust portion removed by the laser. The combination of the two techniques allowed to assess that, even if the two samples had a similar chemical composition, their response to laser cleaning was different on dependence of their different fabric/structure. In fact, in one sample calcium sulphate was still partially retained also after the black crust removal, whereas in the other sample the sulphate layer was almost completely ablated due to its more compact structure. In both cases, laser cleaning operation was shown not to cause any structural modification or mechanical damage of the original stone material. In conclusion, the use of these novel techniques appears very promising for studying the effects of laser ablation on rock samples in order to set the best working conditions for their cleaning.
Biochar has gained agricultural importance as a soil amendment because of its important agricultu... more Biochar has gained agricultural importance as a soil amendment because of its important agricultural properties such as water retention, plant nutrient supplier, promoter of microorganism growth, sequestration action of atmospheric CO 2 , etc. Further, it is a low cost material being produced by recycling. Due to its active sites, biochar can adsorb nutrients so acting as a soil fertilizer. Thus the rapid assessment of nutrients in these materials is essential to ensure quality control for agricultural purposes. This work aimed to develop a simple analytical method based on Laser-Induced Breakdown Spectroscopy (LIBS) to determine Ca in biochar-based fertilizers. In particular , biochar samples enriched with Ca were prepared from peanut shells, residues of eucalyptus and banana fibers. The calibration standards were prepared by matrix matching using a biochar from eucalyptus residues. Different spectral preprocessing were evaluated to enhance the precision and accuracy of the method. However, the matrix effects demanded the use of internal standardization as the appropriate methodology to obtain the best accuracy. A linear correlation coefficient of 0.989 and a linear work range of 1.51–11.23% Ca were obtained using the proposed method, which yielded limits of detection and quantification of 0.45% e 1.51%, respectively. Calcium contents determined by LIBS in biochar-based fertilizers were in good agreement (paired t-test at 95% confidence level) with those determined by using High-Resolution Continuous Source Atomic Absorption Spec-trometry (HR-CS FAAS) as the reference technique. Thus, the importance of internal standardization was demonstrated to be successful for the quantitative analysis of Ca in complex matrices like biochar-based fertilizers.
Laser-induced breakdown spectroscopy (LIBS) is showing to be a promising, quick, accurate, and pr... more Laser-induced breakdown spectroscopy (LIBS) is showing to be a promising, quick, accurate, and practical technique to detect and measure metal contaminants and nutrients in urban wastes and landfill leachates. Although conventional LIBS presents some limitations, such as low sensitivity, when used in the single pulse configuration if compared to other spectroscopic techniques, the use of the double-pulse (DP) configuration represents an adequate alternative. In this work DP LIBS has been applied to the qualitative and quantitative analysis of mercury (Hg) in landfill leachates. The correlation analysis performed between each intensified charge-coupled device pixel and the Hg concentration allowed us to choose the most appropriate Hg emission line to be used for its measure. The normalization process applied to LIBS spectra to correct physical matrix effects and small fluctuations increased from 0.82 to 0.98 the linear correlation of the calibration curve between LIBS and the reference data. The limit of detection for Hg estimated using DP LIBS was 76 mg Kg −1. The cross validation (leave-one-out) analysis yielded an absolute average error of about 21%. These values showed that the calibration models were close to the optimization limit and satisfactory for Hg quantification in landfill leachate.
Laser-induced breakdown spectroscopy (LIBS)
is a technique increasingly used to perform fast semi... more Laser-induced breakdown spectroscopy (LIBS) is a technique increasingly used to perform fast semi-quantitative multi-elemental analyses of various materials without any complex sample preparation, being also suitable for in situ analyses. Few studies have been performed to understand the influence of laser wavelength on LIBS analytical performance on environmental samples. The main goal of this study was to perform a comparative elemental analysis of a number of soils, citrus leaves, and synthetic solid matrices using two different wavelengths, i.e., 532 and 1064 nm of Nd:YAG lasers, and a spectrometer coupled to a non-intensified charge-coupled device camera as the detection system. The emission lines with higher upper energy level, i.e., C I—193.03 (7.685 eV) and Si I—212.41 nm (6.616 eV), were more intense when using the 532 nm than the 1064 nm laser light, whereas the opposite occurred for elements with lower upper energy level, i.e., Ti I—336.12 nm (3.716 eV) and Fe I—368.75 nm (4.220 eV). The observed increase in LIBS signal between the two wavelengths is about 30–50%. The relationship between the line emission intensities and the used excitation wavelengths were associated to the upper level energy of the element.
A soil, a plant and a fertilizer sample were investigated by double-pulse (DP) laser-induced brea... more A soil, a plant and a fertilizer sample were investigated by double-pulse (DP) laser-induced breakdown spectros-copy (LIBS) in orthogonal beam geometry using a reheating configuration. The DP-LIBS signal enhancement was evaluated with respect to the corresponding single-pulse (SP) LIBS as a function of the interpulse delay at various ablation energies. The maximum signal enhancement measured was 155-fold when low ablation energy (4 mJ) and an interpulse delay of 10 μs were used. At high laser energies (≥16 mJ) and interpulse delay of 0.6 μs, the maximum signal enhancement was up to 3-fold. The effect of excitation energies and interpulse delays on emission line intensities was discussed in the various conditions used. The emission line enhancement measured for ionic lines was always higher than that of atomic lines. Plasma excitation temperature and electron density measured as a function of interpulse delays at various ablation energies were shown to be related to the emission line intensities.
Purpose The objective of this review is to survey critically the
results obtained by the applicat... more Purpose The objective of this review is to survey critically the results obtained by the application of laser-induced fluorescence spectroscopy (LIFS) and laser-induced breakdown spectroscopy (LIBS) to the evaluation of the humification degree (HD) of soil organic matter (SOM) directly in untreated, intact whole soils. Materials and methods A large number of soils of various origin and nature, either native or under various cultivations, land use, and management, at various depths, have been studied to evaluate the HD of their SOM directly in intact whole samples. The LIFS spectra were obtained by either a bench or a portable argon laser apparatus that emits UV-VIS light of high power, whereas the LIBS spectra were obtained using a Q-switched Nd:YAG laser at 1064 nm. Results and discussion The close correlations found by comparingHLIF values of whole soil samples with values of earlier proposed humification indexes confirmed the applicability of LIFS to assess the HD of SOM in whole soils. The high correlation found between HDLIBS values and HLIF values showed the promising potential of LIBS for the evaluation HD of SOM. Conclusions The LIFS technique shows to be a valuable alternative to evaluate the HD of SOM by probing directly the whole solid soil sample, thus avoiding the use of any previous chemical and/or physical treatments or separation procedures of SOM from the mineral soil matrix. The emerging application of LIBS to evaluate the HD of SOM in whole soils appears promising and appealing due to its sensitivity, selectivity, accuracy, and precision.
Soil organic carbon (OC) measurement is a crucial factor for quantifying soil C pools and invento... more Soil organic carbon (OC) measurement is a crucial factor for quantifying soil C pools and inventories and monitoring the inherent temporal and spatial heterogeneity and changes of soil OC content. These are relevant issues in addressing sustainable management of terrestrial OC aiming to enhance C sequestration in soil, thus mitigating the impact of increasing CO2 concentration in the atmosphere and related effects on global climate change. Nowadays, dry combustion by an elemental analyzer or wet combustion by dichromate oxidation of the soil sample are the most recommended and commonly used methods for quantitative soil OC determination. However, the unanimously recognized uncertainties and limitations of these classical laboursome methods have prompted research efforts focusing on the development and application of more advanced and appealing techniques and methods for the measurement of soil OC in the laboratory and possibly in situ in the field. Among these laser-induced breakdown spectroscopy (LIBS) has raised the highest interest for its unique advantages. After an introduction and a highlight of the LIBS basic principles, instrumentation, methodologies and supporting chemometric methods, the main body of this review provides an historical and critical overview of the developments and results obtained up-to-now by the application of LIBS to the quantitative measurement of soil C and especially OC content. A brief critical summary of LIBS advantages and limitations/drawbacks including some final remarks and future perspectives concludes this review.
Organic fertilizers are obtained fromwaste of plant or animal origin. One of the advantages of or... more Organic fertilizers are obtained fromwaste of plant or animal origin. One of the advantages of organic fertilizers is that, fromthe composting, it recycleswaste-organic of urban and agriculture origin,whose disposalwould cause environmental impacts. Fast and accurate analysis of both major and minor/trace elements contained in organic mineral and inorganic fertilizers of new generation have promoted the application of modern analytical techniques. In particular, laser induced breakdown spectroscopy (LIBS) is showing to be a very promising, quick and practical technique to detect and measure contaminants and nutrients in fertilizers. Although, this technique presents some limitations, such as a low sensitivity, if compared to other spectroscopic techniques, the use of double pulse (DP) LIBS is an alternative to the conventional LIBS in single pulse (SP). The macronutrients (Ca, Mg, K, P), micronutrients (Cu, Fe, Na, Mn, Zn) and contaminant (Cr) in fertilizer using LIBS in SP and DP configurations were evaluated. A comparative study for both configurations was performed using optimized key parameters for improving LIBS performance. The limit of detection (LOD) values obtained by DP LIBS increased up to seven times as compared to SP LIBS. In general, the marked improvement obtained when using DP system in the simultaneous LIBS quantitative determination for fertilizers analysis could be ascribed to the larger ablated mass of the sample. The results presented in this study show the promising potential of the DP LIBS technique for a qualitative analysis in fertilizers, without requiring sample preparation with chemical reagents.
Gem-quality alexandrite, hiddenite and kunzite,
elbaite and topaz minerals were characterized th... more Gem-quality alexandrite, hiddenite and kunzite,
elbaite and topaz minerals were characterized through a
multi-methodological investigation based on EMPA-WDS,
LA-ICP-MS, and laser-induced breakdown spectroscopy
(LIBS). With respect to the others, the latter technique
enables a simultaneous multi-elemental composition
without any sample preparation and the detection of light
elements, such as Li, Be and B. The criteria for the choice
of minerals were: (a) the presence of chromophore elements
in minor contents and/or as traces; (b) the presence
of light lithophile elements (Li, Be and B); (c) different
crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification
and characterization of minerals, and as a fast
screening method to determine the chemical composition,
including the chromophore and light lithophile elements
Background: The atomic force microscope (AFM) technique has proven to be a useful and versatile t... more Background: The atomic force microscope (AFM) technique has proven to be a useful and versatile tool for the surface characterization of various materials. AFM is capable of providing three dimensional representations of surfaces down to the sub-nanometer scale resolution, with even atomic resolution. The aims of this mini review are to briefly illustrate our personal experience in AFM application for characterizing plasma-treated surface growth on different substrates, such as fluorocarbon (CFx) nano-structured films, polyethylene oxide (PEO) substrates and plasma deposited acrilic acid (pdAA) coatings, and nanocomposite materials, such as polydimethylsiloxane-gold (PDMS-Au) and chitosan-Au (CTO-Au), including the characterization of nanoparticle powder. Methods: The CFx films were obtained by plasma enhanced-chemical vapor deposition in the non-contact AFM mode and pdAA coatings by radiofrequency glow discharges fed with AA vapors and analyzed in the contact AFM mode. Coating morphology was analized by X-Ray photoelectron microscopy (XPS) and water contact angle (WCA). The AFM images of PDMS-Au and CTO-Au nanocomposites was also acquired and analyzed for their topography. Results: The surface topography, the root-mean square (RMS) surface roughness and the mean surface height of CFx coatings plasma-polymerised on polyethyleneterephthalate (PET) substrates were evaluated by AFM as a function of the deposition time, and AFM images obtained were used to gain detailed topographical information of the single nanostructure. By comparing the AFM images of pure PDMS with those of PDMS-Au it was possible to observe the topography of nanofillers embedded in a polymeric matrix or generated on a polymeric surface and also other main differences between the two materials. Conclusion: The AFM technique was shown to be a versatile and promising tool for the morphological characterization of growth of plasma-treated surfaces, such as CFx nano-structured films, PEO substrates and pdAA coatings, and for the topographical characterization of nanocomposite materials such as PDMs-Au and CTO-Au. Finally, AFM can be used as a simple method able to characterize the topography of as-received nanofillers, based on the attachment of the nanopowders on a bi-adhesive tape and on 3D image processing.
Laser–induced breakdown spectroscopy (LIBS) is a fast and reliable technique suitable for the sim... more Laser–induced breakdown spectroscopy (LIBS) is a fast and reliable technique suitable for the simultaneous qualitative and quantitative analysis of major and trace elements in samples of various nature and origin. In last decades, the use of metal accumulator plants, in combination with compost, has become a cheap and sustainable alternative technique to lower soil contamination by toxic heavy metals. In the present work, the LIBS technique has been applied to measure the concentrations of selected elements, including Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Sr, and Zn, in two composts of different origin and nature and four accumulator plant species (Atriplex halimus, Brassica alba, Brassica napus, and Eruca vesicaria). The plant samples were analyzed either as bulk plant material or as specific organs (i.e., shoots and roots). The concentrations measured by LIBS were assessed by complementary induced coupled plasma–optical emission spectroscopy. The significant correlation found between the data obtained by the two techniques (R = 0.732–0.999) supports the feasibility of LIBS for fast screening of major, trace and toxic elements in plant and compost samples. In conclusion, the LIBS technique shows promising for further applications in soil remediation as well as in agriculture.
— A relevant and still unsolved issue in the characterization of diamond coatings deposited on ce... more — A relevant and still unsolved issue in the characterization of diamond coatings deposited on ceramic materials such as hexagonal boron nitride (h-BN) is to enhance the resistance of the substrate to erosion by Kr+ or Xe+ ions generated in the plasma propulsion systems. In this work, diamond films were grown by microwave plasma enhanced chemical vapour deposition on h-BN substrates untreated, for the first time, and pre-treated for short (31-65 min) and long (285-296 min) process times. The morphology of diamond films was analysed by scanning electron microscopy, and atomic force microscopy, and their chemistry and structure by Raman spectroscopy. Microscopy analysis revealed that non-continuous (at short process time) and continuous (at long process time) films were formed, respectively, on both untreated and pre-treated h-BN substrates. In particular, diamond films grown on untreated h-BN substrates exhibited roughness values higher than those of h-BN substrates pre-treated by a conventional ultrasonic method.
Laser-induced breakdown spectroscopy (LIBS) has been in use for decades, but only recently the te... more Laser-induced breakdown spectroscopy (LIBS) has been in use for decades, but only recently the technique has progressed so to allow the construction of efficient handheld, self-contained commercial instruments featuring a large range of capabilities. In particular, the development of portable handheld instruments able to perform non-invasive, spatially resolved, multielement, in-situ analysis has provided an impressive impulse to the scientific investigation of cultural heritage materials. In this work, the design of a handheld LIBS instrument and the first test measurements performed on a fragment of a sedimentary rock monument are presented. A full broadband LIBS emission spectrum with a point and shoot operation was recorded directly within few seconds, so providing information on the elements present in the weathered layer in comparison to the stone surface. Further, the Calibration Free (CF)-LIBS approach was used to test the possibility to obtain a suitable quantitative composition of the main elements present in the sample.
A number of phosphate rocks and organomineral P fertilizers was analyzed comparatively by laser-i... more A number of phosphate rocks and organomineral P fertilizers was analyzed comparatively by laser-induced breakdown spectroscopy (LIBS) in both single-and double-pulse modes associated with two chemometric methods, i.e., principal components analysis (PCA) and partial least squares regression (PLSR). PCA was demonstrated to be a valuable method for the identifi cation of spectral differences between similar samples with only minor compositional differences. The raw and normalized LIBS spectra were able to provide effective identifi cation and discrimination at a 95% confi dence level and in good agreement with the reference concentrations. Results obtained confi rm the promising potential of LIBS for the rapid classifi cation of P fertilizers in situ. Keywords: laser-induced breakdown spectroscopy, phosphate rocks, organomineral fertilizers, principal components analysis, partial least squares regression. Introduction. Optimal fertilizer management is instrumental in obtaining optimized plant productivity and quality by avoiding excessive use that may lead to severe environmental damage such as contamination of surface water and groundwater , especially in areas of intensive crop production, whereas nonoptimal use may cause reduced crop yields. In general, a mineral/inorganic fertilizer is required to guarantee an optimal input of the major nutrients N, P, and K into soil. In contrast, an organomineral fertilizer consists of an appropriate mixture of a mineral rock or an inorganic fertilizer and an organic material generally derived from natural sources such as plant and animal by-products, sewage sludges, municipal biosolid wastes, seaweeds, etc., which can provide a certain amount of major nutrients and organic matter to the soil. In particular, to save the limited primary P reserves available worldwide [1], the use of new P fertilizers consisting of mixtures of organic and secondary mineral P sources available on the market represents a promising alternative. However , correct and effi cient use of organomineral P fertilizers of new generation, i.e., mixtures of phosphate rocks and treated organic wastes, feature a variable composition that requires the development of analytical techniques able to measure and discriminate accurately, rapidly, and cheaply the P content. This will improve their management and effi ciency in agriculture. Laser-induced breakdown spectroscopy (LIBS) is an emerging, rapidly developing and promising analytical technique that can provide real-time, cheap, fast, and easy-to-use multielemental analysis of a variety of materials [2]. LIBS is a minimally destructive method requiring little or no sample pretreatment and no chemicals and produces no disposables. Further, relatively simple, low-cost, compact, and portable instrument confi gurations and packages are available for use outside the laboratory, i.e., on site. Another advantage of LIBS is its suitability for a broad range of multivariate chemometric approaches for data analysis. In the last decades, this technique has been applied in several fi elds [2], including agriculture, e.g., soil, plant, and compost analyses [3–10], but only in the last years has attention been focused on fertilizer analysis [11–16]. The objectives of this work were to evaluate the performance of two LIBS systems associated with two chemometric methods, i.e., principal components analysis (PCA) and partial least squares regression (PLSR), in analyzing comparatively
Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, whic... more Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, which represents one of the world's most relevant carbon reservoirs. In this work, the concentrations of carbon and differences in its composition (humification indexes) were evaluated and compared for several horizons (0 to 390 cm) of three typical Amazonian podzol profiles. Fluorescence spectroscopy was used to investigate the humic acid (HA) fractions of SOM isolated from the different samples. Simple and labile carbon structures appeared to be accumulated in surface horizons, while more complex humified compounds were leached and accumulated in intermediate and deeper Bh horizons. The results suggested that the humic acids originated from lignin and its derivatives, and that lignin could accumulate in some Bh horizons. The HA present in deeper Bh horizons appeared to originate from different formation pathways, since these horizons showed different compositions. There were significant compositional changes of HA with depth, with four types of organic matter: recalcitrant, humified, and old dating; labile and young dating; humified and young dating; and little humified and old dating. Therefore, the humification process had no direct relation with the age of the organic matter in the Amazonian podzols.
A B S T R A C T Laser cleaning is widely used to remove black crusts from weathered limestone mon... more A B S T R A C T Laser cleaning is widely used to remove black crusts from weathered limestone monuments. The cleaning efficiency is commonly tested using conventional analytical techniques, which do not allow to analyze the same sample before and after the treatment. In this paper, micro computed tomography (μ-CT) and micro X-ray fluorescence spectroscopy (μ-XRF) techniques were used for the first time to evaluate the laser cleaning efficiency on two different encrusted quoins collected from a limestone monument. Analyses were carried out non-destructively on the same portion of the two lithotypes before and after the treatment. μ-XRF confirmed the presence of gypsum in the black crust, and showed a marked decrease of S and other typical elements after laser cleaning of both samples. μ-CT clearly showed the different structure of limestone before and after cleaning and the crust portion removed by the laser. The combination of the two techniques allowed to assess that, even if the two samples had a similar chemical composition, their response to laser cleaning was different on dependence of their different fabric/structure. In fact, in one sample calcium sulphate was still partially retained also after the black crust removal, whereas in the other sample the sulphate layer was almost completely ablated due to its more compact structure. In both cases, laser cleaning operation was shown not to cause any structural modification or mechanical damage of the original stone material. In conclusion, the use of these novel techniques appears very promising for studying the effects of laser ablation on rock samples in order to set the best working conditions for their cleaning.
Biochar has gained agricultural importance as a soil amendment because of its important agricultu... more Biochar has gained agricultural importance as a soil amendment because of its important agricultural properties such as water retention, plant nutrient supplier, promoter of microorganism growth, sequestration action of atmospheric CO 2 , etc. Further, it is a low cost material being produced by recycling. Due to its active sites, biochar can adsorb nutrients so acting as a soil fertilizer. Thus the rapid assessment of nutrients in these materials is essential to ensure quality control for agricultural purposes. This work aimed to develop a simple analytical method based on Laser-Induced Breakdown Spectroscopy (LIBS) to determine Ca in biochar-based fertilizers. In particular , biochar samples enriched with Ca were prepared from peanut shells, residues of eucalyptus and banana fibers. The calibration standards were prepared by matrix matching using a biochar from eucalyptus residues. Different spectral preprocessing were evaluated to enhance the precision and accuracy of the method. However, the matrix effects demanded the use of internal standardization as the appropriate methodology to obtain the best accuracy. A linear correlation coefficient of 0.989 and a linear work range of 1.51–11.23% Ca were obtained using the proposed method, which yielded limits of detection and quantification of 0.45% e 1.51%, respectively. Calcium contents determined by LIBS in biochar-based fertilizers were in good agreement (paired t-test at 95% confidence level) with those determined by using High-Resolution Continuous Source Atomic Absorption Spec-trometry (HR-CS FAAS) as the reference technique. Thus, the importance of internal standardization was demonstrated to be successful for the quantitative analysis of Ca in complex matrices like biochar-based fertilizers.
Laser-induced breakdown spectroscopy (LIBS) is showing to be a promising, quick, accurate, and pr... more Laser-induced breakdown spectroscopy (LIBS) is showing to be a promising, quick, accurate, and practical technique to detect and measure metal contaminants and nutrients in urban wastes and landfill leachates. Although conventional LIBS presents some limitations, such as low sensitivity, when used in the single pulse configuration if compared to other spectroscopic techniques, the use of the double-pulse (DP) configuration represents an adequate alternative. In this work DP LIBS has been applied to the qualitative and quantitative analysis of mercury (Hg) in landfill leachates. The correlation analysis performed between each intensified charge-coupled device pixel and the Hg concentration allowed us to choose the most appropriate Hg emission line to be used for its measure. The normalization process applied to LIBS spectra to correct physical matrix effects and small fluctuations increased from 0.82 to 0.98 the linear correlation of the calibration curve between LIBS and the reference data. The limit of detection for Hg estimated using DP LIBS was 76 mg Kg −1. The cross validation (leave-one-out) analysis yielded an absolute average error of about 21%. These values showed that the calibration models were close to the optimization limit and satisfactory for Hg quantification in landfill leachate.
Laser-induced breakdown spectroscopy (LIBS)
is a technique increasingly used to perform fast semi... more Laser-induced breakdown spectroscopy (LIBS) is a technique increasingly used to perform fast semi-quantitative multi-elemental analyses of various materials without any complex sample preparation, being also suitable for in situ analyses. Few studies have been performed to understand the influence of laser wavelength on LIBS analytical performance on environmental samples. The main goal of this study was to perform a comparative elemental analysis of a number of soils, citrus leaves, and synthetic solid matrices using two different wavelengths, i.e., 532 and 1064 nm of Nd:YAG lasers, and a spectrometer coupled to a non-intensified charge-coupled device camera as the detection system. The emission lines with higher upper energy level, i.e., C I—193.03 (7.685 eV) and Si I—212.41 nm (6.616 eV), were more intense when using the 532 nm than the 1064 nm laser light, whereas the opposite occurred for elements with lower upper energy level, i.e., Ti I—336.12 nm (3.716 eV) and Fe I—368.75 nm (4.220 eV). The observed increase in LIBS signal between the two wavelengths is about 30–50%. The relationship between the line emission intensities and the used excitation wavelengths were associated to the upper level energy of the element.
A soil, a plant and a fertilizer sample were investigated by double-pulse (DP) laser-induced brea... more A soil, a plant and a fertilizer sample were investigated by double-pulse (DP) laser-induced breakdown spectros-copy (LIBS) in orthogonal beam geometry using a reheating configuration. The DP-LIBS signal enhancement was evaluated with respect to the corresponding single-pulse (SP) LIBS as a function of the interpulse delay at various ablation energies. The maximum signal enhancement measured was 155-fold when low ablation energy (4 mJ) and an interpulse delay of 10 μs were used. At high laser energies (≥16 mJ) and interpulse delay of 0.6 μs, the maximum signal enhancement was up to 3-fold. The effect of excitation energies and interpulse delays on emission line intensities was discussed in the various conditions used. The emission line enhancement measured for ionic lines was always higher than that of atomic lines. Plasma excitation temperature and electron density measured as a function of interpulse delays at various ablation energies were shown to be related to the emission line intensities.
Purpose The objective of this review is to survey critically the
results obtained by the applicat... more Purpose The objective of this review is to survey critically the results obtained by the application of laser-induced fluorescence spectroscopy (LIFS) and laser-induced breakdown spectroscopy (LIBS) to the evaluation of the humification degree (HD) of soil organic matter (SOM) directly in untreated, intact whole soils. Materials and methods A large number of soils of various origin and nature, either native or under various cultivations, land use, and management, at various depths, have been studied to evaluate the HD of their SOM directly in intact whole samples. The LIFS spectra were obtained by either a bench or a portable argon laser apparatus that emits UV-VIS light of high power, whereas the LIBS spectra were obtained using a Q-switched Nd:YAG laser at 1064 nm. Results and discussion The close correlations found by comparingHLIF values of whole soil samples with values of earlier proposed humification indexes confirmed the applicability of LIFS to assess the HD of SOM in whole soils. The high correlation found between HDLIBS values and HLIF values showed the promising potential of LIBS for the evaluation HD of SOM. Conclusions The LIFS technique shows to be a valuable alternative to evaluate the HD of SOM by probing directly the whole solid soil sample, thus avoiding the use of any previous chemical and/or physical treatments or separation procedures of SOM from the mineral soil matrix. The emerging application of LIBS to evaluate the HD of SOM in whole soils appears promising and appealing due to its sensitivity, selectivity, accuracy, and precision.
Soil organic carbon (OC) measurement is a crucial factor for quantifying soil C pools and invento... more Soil organic carbon (OC) measurement is a crucial factor for quantifying soil C pools and inventories and monitoring the inherent temporal and spatial heterogeneity and changes of soil OC content. These are relevant issues in addressing sustainable management of terrestrial OC aiming to enhance C sequestration in soil, thus mitigating the impact of increasing CO2 concentration in the atmosphere and related effects on global climate change. Nowadays, dry combustion by an elemental analyzer or wet combustion by dichromate oxidation of the soil sample are the most recommended and commonly used methods for quantitative soil OC determination. However, the unanimously recognized uncertainties and limitations of these classical laboursome methods have prompted research efforts focusing on the development and application of more advanced and appealing techniques and methods for the measurement of soil OC in the laboratory and possibly in situ in the field. Among these laser-induced breakdown spectroscopy (LIBS) has raised the highest interest for its unique advantages. After an introduction and a highlight of the LIBS basic principles, instrumentation, methodologies and supporting chemometric methods, the main body of this review provides an historical and critical overview of the developments and results obtained up-to-now by the application of LIBS to the quantitative measurement of soil C and especially OC content. A brief critical summary of LIBS advantages and limitations/drawbacks including some final remarks and future perspectives concludes this review.
Organic fertilizers are obtained fromwaste of plant or animal origin. One of the advantages of or... more Organic fertilizers are obtained fromwaste of plant or animal origin. One of the advantages of organic fertilizers is that, fromthe composting, it recycleswaste-organic of urban and agriculture origin,whose disposalwould cause environmental impacts. Fast and accurate analysis of both major and minor/trace elements contained in organic mineral and inorganic fertilizers of new generation have promoted the application of modern analytical techniques. In particular, laser induced breakdown spectroscopy (LIBS) is showing to be a very promising, quick and practical technique to detect and measure contaminants and nutrients in fertilizers. Although, this technique presents some limitations, such as a low sensitivity, if compared to other spectroscopic techniques, the use of double pulse (DP) LIBS is an alternative to the conventional LIBS in single pulse (SP). The macronutrients (Ca, Mg, K, P), micronutrients (Cu, Fe, Na, Mn, Zn) and contaminant (Cr) in fertilizer using LIBS in SP and DP configurations were evaluated. A comparative study for both configurations was performed using optimized key parameters for improving LIBS performance. The limit of detection (LOD) values obtained by DP LIBS increased up to seven times as compared to SP LIBS. In general, the marked improvement obtained when using DP system in the simultaneous LIBS quantitative determination for fertilizers analysis could be ascribed to the larger ablated mass of the sample. The results presented in this study show the promising potential of the DP LIBS technique for a qualitative analysis in fertilizers, without requiring sample preparation with chemical reagents.
Gem-quality alexandrite, hiddenite and kunzite,
elbaite and topaz minerals were characterized th... more Gem-quality alexandrite, hiddenite and kunzite,
elbaite and topaz minerals were characterized through a
multi-methodological investigation based on EMPA-WDS,
LA-ICP-MS, and laser-induced breakdown spectroscopy
(LIBS). With respect to the others, the latter technique
enables a simultaneous multi-elemental composition
without any sample preparation and the detection of light
elements, such as Li, Be and B. The criteria for the choice
of minerals were: (a) the presence of chromophore elements
in minor contents and/or as traces; (b) the presence
of light lithophile elements (Li, Be and B); (c) different
crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification
and characterization of minerals, and as a fast
screening method to determine the chemical composition,
including the chromophore and light lithophile elements
Background: The atomic force microscope (AFM) technique has proven to be a useful and versatile t... more Background: The atomic force microscope (AFM) technique has proven to be a useful and versatile tool for the surface characterization of various materials. AFM is capable of providing three dimensional representations of surfaces down to the sub-nanometer scale resolution, with even atomic resolution. The aims of this mini review are to briefly illustrate our personal experience in AFM application for characterizing plasma-treated surface growth on different substrates, such as fluorocarbon (CFx) nano-structured films, polyethylene oxide (PEO) substrates and plasma deposited acrilic acid (pdAA) coatings, and nanocomposite materials, such as polydimethylsiloxane-gold (PDMS-Au) and chitosan-Au (CTO-Au), including the characterization of nanoparticle powder. Methods: The CFx films were obtained by plasma enhanced-chemical vapor deposition in the non-contact AFM mode and pdAA coatings by radiofrequency glow discharges fed with AA vapors and analyzed in the contact AFM mode. Coating morphology was analized by X-Ray photoelectron microscopy (XPS) and water contact angle (WCA). The AFM images of PDMS-Au and CTO-Au nanocomposites was also acquired and analyzed for their topography. Results: The surface topography, the root-mean square (RMS) surface roughness and the mean surface height of CFx coatings plasma-polymerised on polyethyleneterephthalate (PET) substrates were evaluated by AFM as a function of the deposition time, and AFM images obtained were used to gain detailed topographical information of the single nanostructure. By comparing the AFM images of pure PDMS with those of PDMS-Au it was possible to observe the topography of nanofillers embedded in a polymeric matrix or generated on a polymeric surface and also other main differences between the two materials. Conclusion: The AFM technique was shown to be a versatile and promising tool for the morphological characterization of growth of plasma-treated surfaces, such as CFx nano-structured films, PEO substrates and pdAA coatings, and for the topographical characterization of nanocomposite materials such as PDMs-Au and CTO-Au. Finally, AFM can be used as a simple method able to characterize the topography of as-received nanofillers, based on the attachment of the nanopowders on a bi-adhesive tape and on 3D image processing.
Laser–induced breakdown spectroscopy (LIBS) is a fast and reliable technique suitable for the sim... more Laser–induced breakdown spectroscopy (LIBS) is a fast and reliable technique suitable for the simultaneous qualitative and quantitative analysis of major and trace elements in samples of various nature and origin. In last decades, the use of metal accumulator plants, in combination with compost, has become a cheap and sustainable alternative technique to lower soil contamination by toxic heavy metals. In the present work, the LIBS technique has been applied to measure the concentrations of selected elements, including Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Sr, and Zn, in two composts of different origin and nature and four accumulator plant species (Atriplex halimus, Brassica alba, Brassica napus, and Eruca vesicaria). The plant samples were analyzed either as bulk plant material or as specific organs (i.e., shoots and roots). The concentrations measured by LIBS were assessed by complementary induced coupled plasma–optical emission spectroscopy. The significant correlation found between the data obtained by the two techniques (R = 0.732–0.999) supports the feasibility of LIBS for fast screening of major, trace and toxic elements in plant and compost samples. In conclusion, the LIBS technique shows promising for further applications in soil remediation as well as in agriculture.
— A relevant and still unsolved issue in the characterization of diamond coatings deposited on ce... more — A relevant and still unsolved issue in the characterization of diamond coatings deposited on ceramic materials such as hexagonal boron nitride (h-BN) is to enhance the resistance of the substrate to erosion by Kr+ or Xe+ ions generated in the plasma propulsion systems. In this work, diamond films were grown by microwave plasma enhanced chemical vapour deposition on h-BN substrates untreated, for the first time, and pre-treated for short (31-65 min) and long (285-296 min) process times. The morphology of diamond films was analysed by scanning electron microscopy, and atomic force microscopy, and their chemistry and structure by Raman spectroscopy. Microscopy analysis revealed that non-continuous (at short process time) and continuous (at long process time) films were formed, respectively, on both untreated and pre-treated h-BN substrates. In particular, diamond films grown on untreated h-BN substrates exhibited roughness values higher than those of h-BN substrates pre-treated by a conventional ultrasonic method.
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Papers by Giorgio S Senesi
is a technique increasingly used to perform fast semi-quantitative
multi-elemental analyses of various materials without
any complex sample preparation, being also suitable
for in situ analyses. Few studies have been performed to
understand the influence of laser wavelength on LIBS analytical
performance on environmental samples. The main
goal of this study was to perform a comparative elemental
analysis of a number of soils, citrus leaves, and synthetic
solid matrices using two different wavelengths, i.e., 532
and 1064 nm of Nd:YAG lasers, and a spectrometer coupled
to a non-intensified charge-coupled device camera
as the detection system. The emission lines with higher
upper energy level, i.e., C I—193.03 (7.685 eV) and Si
I—212.41 nm (6.616 eV), were more intense when using
the 532 nm than the 1064 nm laser light, whereas the opposite
occurred for elements with lower upper energy level,
i.e., Ti I—336.12 nm (3.716 eV) and Fe I—368.75 nm
(4.220 eV). The observed increase in LIBS signal between
the two wavelengths is about 30–50%. The relationship
between the line emission intensities and the used excitation wavelengths were associated to the upper level
energy of the element.
results obtained by the application of laser-induced fluorescence
spectroscopy (LIFS) and laser-induced breakdown
spectroscopy (LIBS) to the evaluation of the humification
degree (HD) of soil organic matter (SOM) directly in untreated,
intact whole soils.
Materials and methods A large number of soils of various
origin and nature, either native or under various cultivations,
land use, and management, at various depths, have been studied
to evaluate the HD of their SOM directly in intact whole
samples. The LIFS spectra were obtained by either a bench or
a portable argon laser apparatus that emits UV-VIS light of
high power, whereas the LIBS spectra were obtained using a
Q-switched Nd:YAG laser at 1064 nm.
Results and discussion The close correlations found by comparingHLIF
values of whole soil samples with values of earlier
proposed humification indexes confirmed the applicability of
LIFS to assess the HD of SOM in whole soils. The high
correlation found between HDLIBS values and HLIF values
showed the promising potential of LIBS for the evaluation
HD of SOM.
Conclusions The LIFS technique shows to be a valuable alternative
to evaluate the HD of SOM by probing directly the
whole solid soil sample, thus avoiding the use of any previous chemical and/or physical treatments or separation procedures
of SOM from the mineral soil matrix. The emerging application
of LIBS to evaluate the HD of SOM in whole soils appears
promising and appealing due to its sensitivity, selectivity,
accuracy, and precision.
monitoring the inherent temporal and spatial heterogeneity and changes of soil OC content. These are
relevant issues in addressing sustainable management of terrestrial OC aiming to enhance C sequestration
in soil, thus mitigating the impact of increasing CO2 concentration in the atmosphere and related
effects on global climate change. Nowadays, dry combustion by an elemental analyzer or wet combustion
by dichromate oxidation of the soil sample are the most recommended and commonly used methods for
quantitative soil OC determination. However, the unanimously recognized uncertainties and limitations
of these classical laboursome methods have prompted research efforts focusing on the development and
application of more advanced and appealing techniques and methods for the measurement of soil OC in
the laboratory and possibly in situ in the field. Among these laser-induced breakdown spectroscopy
(LIBS) has raised the highest interest for its unique advantages. After an introduction and a highlight of
the LIBS basic principles, instrumentation, methodologies and supporting chemometric methods, the
main body of this review provides an historical and critical overview of the developments and results
obtained up-to-now by the application of LIBS to the quantitative measurement of soil C and especially
OC content. A brief critical summary of LIBS advantages and limitations/drawbacks including some final
remarks and future perspectives concludes this review.
that, fromthe composting, it recycleswaste-organic of urban and agriculture origin,whose disposalwould cause
environmental impacts. Fast and accurate analysis of both major and minor/trace elements contained in organic
mineral and inorganic fertilizers of new generation have promoted the application of modern analytical techniques.
In particular, laser induced breakdown spectroscopy (LIBS) is showing to be a very promising, quick
and practical technique to detect and measure contaminants and nutrients in fertilizers. Although, this technique
presents some limitations, such as a low sensitivity, if compared to other spectroscopic techniques, the use of
double pulse (DP) LIBS is an alternative to the conventional LIBS in single pulse (SP). The macronutrients (Ca,
Mg, K, P), micronutrients (Cu, Fe, Na, Mn, Zn) and contaminant (Cr) in fertilizer using LIBS in SP and DP configurations
were evaluated. A comparative study for both configurations was performed using optimized key parameters
for improving LIBS performance. The limit of detection (LOD) values obtained by DP LIBS increased
up to seven times as compared to SP LIBS. In general, the marked improvement obtained when using DP system in the simultaneous LIBS quantitative determination for fertilizers analysis could be ascribed to the larger ablated
mass of the sample. The results presented in this study show the promising potential of the DP LIBS technique for
a qualitative analysis in fertilizers, without requiring sample preparation with chemical reagents.
elbaite and topaz minerals were characterized through a
multi-methodological investigation based on EMPA-WDS,
LA-ICP-MS, and laser-induced breakdown spectroscopy
(LIBS). With respect to the others, the latter technique
enables a simultaneous multi-elemental composition
without any sample preparation and the detection of light
elements, such as Li, Be and B. The criteria for the choice
of minerals were: (a) the presence of chromophore elements
in minor contents and/or as traces; (b) the presence
of light lithophile elements (Li, Be and B); (c) different
crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification
and characterization of minerals, and as a fast
screening method to determine the chemical composition,
including the chromophore and light lithophile elements
is a technique increasingly used to perform fast semi-quantitative
multi-elemental analyses of various materials without
any complex sample preparation, being also suitable
for in situ analyses. Few studies have been performed to
understand the influence of laser wavelength on LIBS analytical
performance on environmental samples. The main
goal of this study was to perform a comparative elemental
analysis of a number of soils, citrus leaves, and synthetic
solid matrices using two different wavelengths, i.e., 532
and 1064 nm of Nd:YAG lasers, and a spectrometer coupled
to a non-intensified charge-coupled device camera
as the detection system. The emission lines with higher
upper energy level, i.e., C I—193.03 (7.685 eV) and Si
I—212.41 nm (6.616 eV), were more intense when using
the 532 nm than the 1064 nm laser light, whereas the opposite
occurred for elements with lower upper energy level,
i.e., Ti I—336.12 nm (3.716 eV) and Fe I—368.75 nm
(4.220 eV). The observed increase in LIBS signal between
the two wavelengths is about 30–50%. The relationship
between the line emission intensities and the used excitation wavelengths were associated to the upper level
energy of the element.
results obtained by the application of laser-induced fluorescence
spectroscopy (LIFS) and laser-induced breakdown
spectroscopy (LIBS) to the evaluation of the humification
degree (HD) of soil organic matter (SOM) directly in untreated,
intact whole soils.
Materials and methods A large number of soils of various
origin and nature, either native or under various cultivations,
land use, and management, at various depths, have been studied
to evaluate the HD of their SOM directly in intact whole
samples. The LIFS spectra were obtained by either a bench or
a portable argon laser apparatus that emits UV-VIS light of
high power, whereas the LIBS spectra were obtained using a
Q-switched Nd:YAG laser at 1064 nm.
Results and discussion The close correlations found by comparingHLIF
values of whole soil samples with values of earlier
proposed humification indexes confirmed the applicability of
LIFS to assess the HD of SOM in whole soils. The high
correlation found between HDLIBS values and HLIF values
showed the promising potential of LIBS for the evaluation
HD of SOM.
Conclusions The LIFS technique shows to be a valuable alternative
to evaluate the HD of SOM by probing directly the
whole solid soil sample, thus avoiding the use of any previous chemical and/or physical treatments or separation procedures
of SOM from the mineral soil matrix. The emerging application
of LIBS to evaluate the HD of SOM in whole soils appears
promising and appealing due to its sensitivity, selectivity,
accuracy, and precision.
monitoring the inherent temporal and spatial heterogeneity and changes of soil OC content. These are
relevant issues in addressing sustainable management of terrestrial OC aiming to enhance C sequestration
in soil, thus mitigating the impact of increasing CO2 concentration in the atmosphere and related
effects on global climate change. Nowadays, dry combustion by an elemental analyzer or wet combustion
by dichromate oxidation of the soil sample are the most recommended and commonly used methods for
quantitative soil OC determination. However, the unanimously recognized uncertainties and limitations
of these classical laboursome methods have prompted research efforts focusing on the development and
application of more advanced and appealing techniques and methods for the measurement of soil OC in
the laboratory and possibly in situ in the field. Among these laser-induced breakdown spectroscopy
(LIBS) has raised the highest interest for its unique advantages. After an introduction and a highlight of
the LIBS basic principles, instrumentation, methodologies and supporting chemometric methods, the
main body of this review provides an historical and critical overview of the developments and results
obtained up-to-now by the application of LIBS to the quantitative measurement of soil C and especially
OC content. A brief critical summary of LIBS advantages and limitations/drawbacks including some final
remarks and future perspectives concludes this review.
that, fromthe composting, it recycleswaste-organic of urban and agriculture origin,whose disposalwould cause
environmental impacts. Fast and accurate analysis of both major and minor/trace elements contained in organic
mineral and inorganic fertilizers of new generation have promoted the application of modern analytical techniques.
In particular, laser induced breakdown spectroscopy (LIBS) is showing to be a very promising, quick
and practical technique to detect and measure contaminants and nutrients in fertilizers. Although, this technique
presents some limitations, such as a low sensitivity, if compared to other spectroscopic techniques, the use of
double pulse (DP) LIBS is an alternative to the conventional LIBS in single pulse (SP). The macronutrients (Ca,
Mg, K, P), micronutrients (Cu, Fe, Na, Mn, Zn) and contaminant (Cr) in fertilizer using LIBS in SP and DP configurations
were evaluated. A comparative study for both configurations was performed using optimized key parameters
for improving LIBS performance. The limit of detection (LOD) values obtained by DP LIBS increased
up to seven times as compared to SP LIBS. In general, the marked improvement obtained when using DP system in the simultaneous LIBS quantitative determination for fertilizers analysis could be ascribed to the larger ablated
mass of the sample. The results presented in this study show the promising potential of the DP LIBS technique for
a qualitative analysis in fertilizers, without requiring sample preparation with chemical reagents.
elbaite and topaz minerals were characterized through a
multi-methodological investigation based on EMPA-WDS,
LA-ICP-MS, and laser-induced breakdown spectroscopy
(LIBS). With respect to the others, the latter technique
enables a simultaneous multi-elemental composition
without any sample preparation and the detection of light
elements, such as Li, Be and B. The criteria for the choice
of minerals were: (a) the presence of chromophore elements
in minor contents and/or as traces; (b) the presence
of light lithophile elements (Li, Be and B); (c) different
crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification
and characterization of minerals, and as a fast
screening method to determine the chemical composition,
including the chromophore and light lithophile elements