Scanning Electron Microscopy Coupled With Energy Dispersive X-ray Research Articles

New insights into Zwischgold application from a multi-analytical survey of late medieval polychrome sculptures at the Swiss National Museum

Zwischgold, or part gold, is a bi-layered metal foil made from gold and silver, popular in European sculptures from the 14th century. It is notoriously difficult to unambiguously identify and to study in detail, due to its close appearance to gold leaf (when still well preserved) and complicated individual situations. Although Zwischgold is nowadays commonly viewed as an economical substitute for gold leaf, arguments regarding its function have circulated for decades. In order to understand the application and related functions of Zwischgold in late medieval sculptures, a survey of 162 objects was recently implemented at the Swiss National Museum Collection Centre, focusing on polychrome wooden sculptures mainly dated 1400–1550 and produced in southern Germany and Switzerland. Handheld X-ray fluorescence (XRF) measurements show a high rate of correlated silver and gold signals mainly in a proportion range of 1:5–3:1, indicating Zwischgold in extremely diverse areas such as hair, beard, crown, gown fold, bordure, dalmatic, undergarment and attribute of saint statues, as well as altar background, frame and framework. This non-invasive XRF analysis is a first step to efficiently locate Zwischgold applied areas and obtain basic statistics regarding the Zwischgold applied artefacts. It provides objective evidence showing that the reasons for medieval Zwischgold application are not limited to cost-saving, but include other factors such aesthetics, symbolism, workshop preference and workability. We discuss such factors with some illustrative case studies, in which visual light microscope (VLM) and scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) measurements on samples exhibit certain technological features of Zwischgold of that epoch, including its foil structure, thickness and materials compositions.

Evaluation of the Bioactivity of Surface Modified Polyetheretherketone (PEEK) as an Implant Material: An In Vitro Study.

Purpose:The purpose of this study was to evaluate the bioactivity of polyetheretherketone (PEEK) used as an implant material after surface modification by electron beam deposition of titanium.Materials and Methods:Twenty-two samples of PEEK were obtained from a single manufacturer, water jet sectioned, and divided randomly into two groups of eleven each (Group I and Group II). Eleven PEEK samples from Group II were coated with Grade II commercially pure titanium by electron beam deposition technique. One representative sample from each group was evaluated for surface roughness, topography and composition using three dimensional surface profilometer, scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX) analysis. Simulated body fluid (SBF) was prepared and calcium (Ca) content in it was quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) technique. Ten samples from each group were then immersed in SBF for a period of 21 days and amount of calcium depletion was analyzed to determine the bioactivity of two groups. Surface characteristics and elemental composition of immersed samples were analyzed by SEM-EDX and correlated with results of ICP-MS tests. The data obtained were then subjected to statistical analysis using independent t-test.Results:Group II samples showed a significant increase in surface roughness compared to Group I (P < 0.02). There were significant differences in Ca depletion of Group I and Group II samples when compared to preimmersion Ca content (P < 0.001). When compared between two Groups, Group II samples showed higher Ca depletion (P < 0.001).Conclusion:Within the limitations of this study, it was concluded that PEEK dental implants which were surface modified by electron beam deposition of titanium had enhanced bioactivity when compared to unmodified PEEK. Hence, they can serve as a valuable alternative to conventional dental implant materials.

Mercury removal from simulated waste water by chitosan nano composite embedded with leaf extract of Brassica Gongylodes

Chitosan a natural linear bio-poly amino saccharide is extensively used for the removal of heavy metals. Brassica Gongylodes a native of Northern Europe is reported to be rich in polyphenols and flavonoids. In present study a novel green nanocomposite has been developed by combining chitosan and Brassica Gongylodes leaf extract. Freshly prepared chitosan nanoparticles embedded with Brassica Gongylodes leaf extract. Developed green nanocomposite was investigated as bio adsorbent for the removal of mercury metal from simulated waste water. Physico-chemical, morphological and elemental characterization of prepared green nanocomposite prior to adsorption was commenced using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscope coupled with Energy dispersive x-ray (SEM-EDX) techniques. SEM studies confirm the formation of nanoparticles of chitosan. EDX analysis indicated the presence of new and change in concentration of many compositional elements. In diffractrogram of chitosan nanoparticles impregnated with Brassica Gongylodes leaf extract several diffraction peaks of high angle were observed which were missing in the nanoparticles of chitosan diffractrogram. Batch adsorption results revealed that maximum adsorption of mercury was found with 50 mg of adsorbent when contact time was 45 min at 10 pH. In thermodynamic studies it has been found that process is spontaneous and feasible. For kinetic studies different kinetic parameters, equilibrium sorption capacities, rate constants, and related correlation coefficients were calculated. Result shows that adsorption process could be best defined by the pseudo second order kinetic equation which suggests that adsorption process is carried out probably by chemisorption. Thus study shows that chitosan nano composite embedded with Brassica Gongylodes leaf extract is a promising adsorbent for mercury adsorption from simulated wastewater.

CoFe2O4@SiO2: A magnetically recyclable heterogeneous catalyst for the synthesis of spirooxindole derivatives

We described the characterization, preparation, and catalytic application of CoFe2O4@SiO2 nanoparticle. The characterization was done using transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX), and Fourier transform infrared (FT-IR) analyses. Using Scherrer’s approximation and powder X-ray diffractometry (XRD), an average crystallite size is determined from the full width at half the maximum of the strongest reflection. In the synthesis of spirooxindoles of malononitrile, various isatins with 1,3-dicarbonyl compounds, The CoFe2O4@SiO2 efficiency is investigated. Good to excellent yields are observed in the coupling products, which was in result of excellent catalytic activity of the nanocatalyst. Furthermore, at least five times of the recoverability and reusability of CoFe2O4@SiO2 without any apparent decrease in the activity and selectivity are confirmed. This confirmed the high efficiency and stability of the nanocatalyst under the reaction conditions and during the recycling stages.

Development and characterization of low temperature metallic glazes in Na2O-B2O3-SiO2 (NBS) system

This paper presents the results of an investigation into crystal formation in NBS system for glaze with metallic appearance experimentally produced by embedding metallic substances as AgNO3, BaCl2, CuSO4 and CuCO3 and their characterizations. Composition of NBS was calculated by using Seger Method. According to the quantity of components, crystal phases were marked on Na2O-B2O3-SiO2 ternary diagrams. The amount of AgNO3 (2 wt%) was kept constant that other metallic substances (BaCl2, CuSO4 and CuCO3) were added in an amount of 5 wt% as had an impact on the mechanism of crystalline phase growth. These glaze compositions were applied over the surface of the commercial bodies and fired at 1040 °C, cooled to 750 °C and then reduced in the reductive atmosphere in order to obtain metallic layer on glaze surfaces for 20 min. These glaze layers characterized under mineralogical, microstructural and chemical points of view by means of X-Ray Diffraction (XRD), optical microscopy (OM), Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX) and Ulltraviolet Visible Spectroscopy (UV–Vis) techniques. The results showed that silver and copper particles/crystals developed near/on the glaze surfaces creating multicolored metallic shine. Diffusion of metallic particles/crystals shown on the glazed layers as Ag and Cu followed by nucleation and growth in a reductive atmosphere.

Material flow influence on the quality of molded parts

This paper focuses on a new occurrence mechanism of the flow marks, which appear on the surface of injection-molded parts, through characterization of the part surface structure. Injection-molded parts involving long flow lengths can exhibit visible flow defects characterized by alternating glossy and dull bands on the polymer surface, which have approximately the same direction with the material flow front. These flow defects are considered to have strong negative effect on the appearance of the molded component and thus on the perceived quality. The reasons for the appearance of these stripes are not entirely clear. Defect flow marks (shiny areas) were cut from the molded part and analyzed using optical microscopy, Fourier transform infrared spectroscopy, laser Raman spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray (SEM/EDX) spectroscopy. Raman spectra detected differences between spectra of defect area and of the reference one. The EDX analysis revealed that the defect area contains slightly more quantity of talc (Mg and Si). This happened because of material flow morphology in the areas where the molded part presents ribs. The flow of melted resin through an enlargement (rib) results in a decrease in flow velocity, and consequently, a pressure rise will occur and it also involves a vortex development. Therefore, the shear stress in this area is higher than upstream and downstream ones, and it will cause a delay of the flow stream, a premature solidification of the melted resin and ribs flow marks occurrence.

Enhancement performance of carbon electrode for supercapacitors by quinone derivatives loading via solvent-free method

Abstract Activated carbon (AC) from coconut shell, surface area of 764 m2 g−1, was functionalized with various quinone derivatives (anthraquinone (AQ), 9,10-phenanthrenequinone (PQ) or tetrachlorohydroquinone (TCHQ)) via a sublimation method for supercapacitor application. The properties of modified activated carbons were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption. The results showed a supercapacitor containing AC modified with 16 wt% AQ achieved higher specific capacitance than other quinone derivatives. AQ/AC performed specific capacitance about 485 F g−1 at a current density of 1.0 A g−1, resistance of 2.25 Ω and specific capacitance loss of 1.2% after 1000 charge-discharge cycles. The experimental data is in good agreement with the computational results of quinone adsorption on graphene surface; the lowest interaction energy (IE) of -28.0 kcal mol−1 was obtained for AQ loading model. The modified AC successfully prepared by a solvent-free method which could be further developed as low-cost and environmentally friendly electrode materials for high-performance supercapacitors.

The corrosion inhibition mechanisms of Ce(III) ions and triethanolamine on graphite—AA2024-T3 galvanic couples revealed by localised electrochemical techniques

The inhibition mechanism of cerium chloride and triethanolamine on the galvanic corrosion of AA2024-T3/graphite in NaCl electrolyte was investigated by localised electrochemical techniques. Quasi-simultaneous measurements of ionic current densities and pH were performed by the Scanning Vibrating Electrode Technique (SVET) and Scanning Ion-Selective Electrode Technique (SIET). Surfaces were analysed by Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX) and X-Ray Photoelectron Spectroscopy (XPS). This work follows a recent publication (Coelho et al. 2018) and discusses the effect of inhibitors on two AA2024-T3/graphite galvanic couples, constructed with two different areas ratio, evidencing that this parameter significantly influences the corrosion and corrosion inhibition process.

Assessment of Capacitive Deionization Microfluidic Desalination via Electrode Microstructure Analysis

Abstract Microfluidics desalination technology is an immerging path of technology to utilize the domination of many apparent fluids physical properties (viscosity and surface tension) in the micro-flow systems. The traditional and commercially applied desalination methods suffer from several drawbacks such as high power consumption and low separation performance. It is believed that the flow of liquids in the micro-scaled structures will optimize the mixing efficiency and that will definitely lead to higher desalination performance. The present work introduces a microfluidics chip for water desalination. The chip was fabricated using polydimethylsiloxane soft lithography method. The aluminium electrodes were coated with carbon powder in order to avoid dissolution. The desalination efficiency was analyzed and evaluated with different feed flow rate (70, 90, 110, 130 and 150 mL/h) using capacitive deionization method. The dissolution of electrodes were observed for 35 min with the feed flow rate ranging 70 to 150 mL/h. The desalination efficiency with aluminium electrodes and carbon-coated electrodes was 65% and 58% respectively. The microstructure of electrode was analyzed by using scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX). The result revealed that the aluminium electrode experienced dissolution at 70 mL/h while the carbon-coated electrodes start to dissolve at t = 30 min. The findings in this work shows that the dissolution time for electrodes were relies on its surface properties.

A transparent electrode with water-oxidizing activity

Hydrogen production by water splitting is a promising method to store energy. Water-oxidation reaction is a bottleneck in water-splitting systems. Herein, a mononuclear nickel(II) phosphine complex with 1,2-bis(dicyclohexylphosphino)ethane ligand, was synthesized and characterized by X-ray crystallography method. The water-oxidizing catalyst under the electrochemical condition was studied. The role of Ni compound for the water-oxidation reaction on the surface of fluorine-doped tin oxide as one of the true catalysts was investigated by the electrochemical methods and Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM/EDX) Spectroscopy. The big ligand around the Ni ion causes a very small size of Ni-based particles on the surface of the electrode, which are the active catalysts for the water-oxidation reaction. Such small nanosized Ni-based compounds are transparent and have no effect on the transparency of the obtained fluorine-doped tin oxide. Thus, it is a promising method to synthesize a transparent fluorine-doped tin oxide with water-oxidizing activity.

Facile synthesis of polypyrrole encapsulated V2O5 nanohybrids for visible light driven green sonophotocatalytic degradation of antibiotics

The present work reports for the first time ultrasound-assisted facile synthesis of stable polypyrrole/vanadium oxide (Ppy/V2O5) nanohybrids using various loadings of the conducting polymer. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) investigations confirmed the formation of the nanohybrids via synergistic interaction between C of Ppy with O of V2O5. The loading of Ppy in the nanohybrids was found to be 15%, 30% and 45% respectively which was confirmed by thermogravimetric analysis (TGA) and scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) analyses. High resolution transmission electron microscopy (HR-TEM) revealed the formation of nanorods of V2O5 and a mixed morphology of spheres and rods in case of Ppy/V2O5 nanohybrids. X-ray diffraction (XRD) showed crystalline morphology of the nanohybrids but upon increasing the loading of Ppy up to 45%, the layered morphology of V2O5 was partially distorted. The band gap of Ppy/V2O5 nanohybrids was calculated to be 2.17eV, 2.16eV, and 2.14eV for Ppy/V2O5-15/85, Ppy/V2O5-30/70, and Ppy/V2O5-45/55 respectively from diffuse reflectance spectroscopy (DRS) studies. The surface area was determined by BET analysis and was found to be 25.91m2/g, 43.67m2/g, 53.51m2/g for Ppy/V2O5-15/85, Ppy/V2O5-30/70 and Ppy/V2O5-45/55 respectively. Highly efficient visible-light driven photocatalysis of Ppy/V2O5 nanohybrids was demonstrated by achieving 72–76% degradation of the antibiotics - ciprofloxacin (CIP) and erythromycin (E-mycin) within 50min. Radical trapping experiments validated that the photogenerated OH and O2− radicals were the two main photoactive species responsible for photocatalytic degradation. A plausible mechanism of photocatalytic degradation using Ppy/V2O5 nanohybrids under visible light irradiation is also proposed. Ppy was found to act as visible-light photosensitizer which aided the transfer of electrons to the conduction band of V2O5. The degraded drug fragments were identified using liquid chromatography–mass spectrometry (LC-MS).

Examination and analysis of Indian silver punch‐marked coins employing WD‐XRF and other noninvasive techniques

The archaeometallurgical analysis of ancient silver coins provides useful information regarding fabrication methodology, provenance, and trade route and explains large diversification in elementary composition, weight, and physical features. The present investigation deals with the chemical analysis and examination of the processing history of Indian punch‐marked silver coins dating to 400–200 bc. The chemical analysis was carried out by wavelength dispersive X‐ray fluorescence and X‐ray Diffraction (XRD). The microstructural examination was performed using field emission scanning electron microscope (FE‐SEM) and different phases were identified by Scanning Electron Microscopy coupled with Energy Dispersive X‐ray (SEM‐EDX) Spectroscopy. It was observed that all eight coins were manufactured with silver‐copper alloy. The ore used for obtaining silver was argentiferous galena, and cupellation was carried with perfection. The absence of slag inclusions as revealed by SEM examination indicated that coins (numbers 2, 4, 5, and 7) were cast from a molten state. The presence of Cu2O, CuO, and Ag2O on the surfaces of the coins was confirmed by XRD. The formed oxide layers provided protection and saved the coins from bulky corrosion products. The data reveal great divergence of coin surface from the composition of the core with the far better metallurgical process for refining of silver for this hoard.

Inhibitory effect of three phenacyl derivatives on the oxidation of sphalerite (ZnS) in air-equilibrated acidic solution

Three phenacyl derivatives have been investigated as potential inhibitors for the aqueous oxidation of sphalerite (ZnS) in air-equilibrated solutions of HCl (pH 2.5 and 25 °C) using potentyodynamic polarization, aqueous batch experiments, scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, Raman scattering and quantum chemical calculations. Findings show that the studied phenacyl derivatives are inhibitors of sphalerite aqueous oxidation. Quantum chemical calculations indicate that the adsorption of phenacyl derivatives on ZnS is energetically favorable and accounts for the observed inhibiting effects.

Coking Tendency of 25Cr-35Ni Alloys: Influence of Temperature, Sulfur Addition, and Cyclic Aging

25Cr-35Ni base alloys are the most frequently used materials for steam cracking reactors. The influence of cyclic aging, reactor temperature, and adding sulfur containing compounds before or during cracking on the rate of coke deposition on a classical 25Cr-35Ni alloy is evaluated using a jet stirred reactor equipped with an electrobalance. As expected, the initial and asymptotic coking rate increased with increasing reactor temperature. Scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) analysis indicated that more Ni and Fe is present on the surface at higher cracking temperatures. Presulfidation led to increased coke deposition and decreased CO yields compared to the reference. When a sulfur containing compound was added continuously, coke deposition increased significantly but carbon oxide formation was suppressed. A pronounced amount of coke was measured in the reactor, followed by suppressed generated amounts of carbon oxides downstream. When combined with the continuous add...

Kinetic study of Ni(II) removal using ion flotation: Effect of chemical interactions

In this kinetic study, the separation mechanism and chemical interactions of Ni(II) ion removal from synthetic wastewater were evaluated by ion flotation. The influence of effective factors such as pH, collector concentration, ionic strength, activity coefficient, foreign salts, and gas type were also evaluated on the kinetics of Ni(II) ion removal and water removal during the process. By increasing pH, the Ni(II) removal rate increased, in which foam fractionation occurred at pH levels of 3, 5.5, and 8 and ion flotation at a pH level of 9.7. The difference between foam fractionation and ion flotation is related to the flotation of a soluble or insoluble complex of the ion–collector. The kinetic study was also used to determine the separation mechanism. The order of Ni(II) foam fractionation was two, while the order of Ni(II) ion flotation was one. The Ni(II) removal rate was faster than the water removal rate, which indicated that Ni(II) ion removal was carried out by true flotation. The effect of chemical interactions on the characterization of the sublate (insoluble complexes formed in the scum layer) were studied using scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results showed that the chemical conditions have an important effect on the Ni(II) ion flotation efficiency.

The main factors effecting the efficiency of Zn(II) flotation: Optimum conditions and separation mechanism

In this study, the effects of chemical conditions on the recovery of Zn(II) and water during the ion flotation process were evaluated using a central composite design (CCD) of response surface methodology. The optimum effective parameters including pH, collector and frother concentration were determined. The results showed that the pH and collector concentration were effective factors for the efficiency of Zn(II) flotation. The effects of collector and frother concentration on the characterization of sublate and the complexation of sodium dodecyl sulphate with Zn(II) were studied using scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results show that foam fractionation occurred at a pH of 1.5, 3 and 5.5 and ion flotation at a pH of 8.

Thermodynamic studies on adsorption of lead (II) Ion from aqueous solution using magnetite, activated carbon and composites

Magnetite nanoparticles, activated carbon and their composite were synthesized in the laboratory and their adsorption capacities were tested for the removal of Pb (II) ion from aqueous solutions. Magnetite was prepared using co-precipitation method and the activated carbon prepared by chemical activation. The prepared adsorbents were characterized by some physico-chemical and spectroscopic methods. The instrumental techniques used for characterizing the adsorbents include Fourier Transform Infrared (FTIR), X –ray Fluorescence (XRF) and Scanning Electron Microscopy coupled with energy dispersive X-ray (SEM-EDX). The comparative adsorption of Pb (II) ion from aqueous solution onto different adsorbents was investigated using batch adsorption experiment at room temperature. The effects of initial metal ion concentration, contact time, adsorbent dosage, and temperature were evaluated. The activated carbon shows a structure like a honeycomb with a pattern of hollows and ridges, while the EDX shows an abundance of carbon. The results showed that maximum removal of Pb (II) ions was achieved with magnetite nanoparticles at a concentration of 100 mg/L within 60 minutes. The adsorption of Pb (II) on the all adsorbents best fitted the Langmuir adsorption isotherm based on its better regression coefficient. Kinetics result showed that the adsorption followed pseudo-second order perfectly implying chemisorption. Thermodynamic result revealed ΔG values of (-6.73 to -0.502 kJ/mol), depicting that the adsorption is feasible and spontaneous. Also, the reaction is endothermic as evident in the positive value of ΔH (0.779 to 22.815 kJ/mol) and positive value of ΔS means there is an irregular increase in the randomness at the solid-solution interface of the adsorbents. The results obtained revealed that the adsorbents prepared can be used for the treatment of Pb (II)-based effluents. Keywords: Adsorption, Pb (II) ion, Kinetics, Thermodynamics

Removal of nickel ions on residue of alginate extraction from Sargassum filipendula seaweed in packed bed

ABSTRACTThe residue of the alginate extraction, which has been shown as a good alternative material in the removal of toxic metals from industrial wastewater, is little explored as a biosorbent material. This study evaluated the removal of nickel ion in a fixed bed onto the residue of alginate extraction from Sargassum filipendula seaweed. The biosorption process in a dynamic fixed‐bed system evaluated the influence of flow rate and feed concentration, by mass transfer zone (MTZ) and the total removal percentage (%Remt). In order to assess the metal recovery potential and the lifetime of the column, two cycles of adsorption/desorption were performed. The continuous adsorption process was simulated using different dynamic models such as Bohart and Adams, Clark, Thomas, Yan et al., and Yoon and Nelson models. The best predictive model was Yan et al. Techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive X‐ray (SEM‐EDX), helium gas picnometry, mercury porosimetry, and N2 physisorption (BET) were performed in order to compare the residue before adsorption with the material after the process. The results showed that the residue can be used to treat toxic metal contaminated effluents by biosorption processes efficiently.

Experimental assessment of electrolysis method in production of biodiesel from waste cooking oil using zeolite/chitosan catalyst with a focus on waste biorefinery

Used waste cooking oil (WCO) or frying oils are being considered as rich sources of economical feedstock for biodiesel production. To carry out the process of trans-esterification of WCO to methyl esters (biodiesel), zeolite/chitosan/KOH composite was used as solid heterogeneous catalysts. The composite was analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEM-EDX) analysis, and X-ray diffraction (XRD) analysis. It was found that the treatment of the natural zeolite (clinoptilolite zeolite) with KOH significantly decreased its silica content by desilication and increased its K+ content by formation of hydroxylpotaslite. Electrolysis method (EM) is used as an applicable technology for recovery of energy and resources during waste treatment. Theoretically, EM can convert any biodegradable waste into H2, O2, biofuels, as well as other by-products such as glycerol. However, the system efficacy can vary significantly under different circumstances. The conversion of biodiesel from WCO was obtained for 1wt.% catalyst concentration and alcohol/oil ratio of 1:7 at 40V in the presence of water as 2wt.% of the whole solution in 3h, produced 93% yield. The optimum conversion process was achieved as a result of using co-solvent as acetone. Fourier Transform Infrared (FT-IR) and Viscosity characterization were used the assessing techniques for detection of WCO and biodiesel.

Application of Imaging Techniques to Cases of Drug-Induced Crystal Nephropathy in Preclinical Studies.

A number of drugs can cause precipitates within renal tubules leading to crystal nephropathy. Crystal nephropathy is usually an exposure-related finding and is not uncommon in preclinical studies, where high doses are tested. An understanding of the nature of precipitates is important for human risk assessment and further development. Our aim was to investigate the ability of various imaging techniques to detect the presence of drugs or metabolites in renal crystals. We applied matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) imaging, Raman and infrared microspectroscopy, scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) spectroscopy and standard histopathology to cases of drug-induced crystal nephropathy, induced in rodents and primates by 4 compounds. MALDI-FTICR MS imaging enabled the identification of the drug-related crystal content in all 4 cases of nephropathy, without reference material and with high accuracy. Crystals were composed of unchanged parent drug and/or metabolites. Similar results were obtained using Raman and infrared microspectroscopy for 2 compounds. In the absence of reference standards of metabolites, Raman and infrared microspectroscopy showed that the crystals consisted of components similar, but not identical, to the administered drug for the other compounds, a limitation for these techniques. SEM/EDX showed which counter ions were colocalized with the identified drug-related material, complementing the MALDI-FTICR MS findings. Therefore, we recommend MALDI-FTICR MS as a first-line methodology to characterize crystal nephropathies. Raman and infrared microspectroscopy may be useful when MALDI-FTICR MS imaging cannot be applied. SEM/EDX could be considered as a complementary technology.