Energy Dispersive X-ray Spectrophotometry Research Articles

Durability of Non-Heat-Cured Geopolymer Mortars Containing Metakaolin and Ground Granulated Blast Furnace Slag

This study presents the durability, strength and microstructure of non-heat-cured geopolymer mortars (GMs) containing metakaolin (MK), ground granulated blast furnace slag (GGBFS), potassium hydroxide (KOH), sodium metasilicate (Na2SiO3), CEN sand and network water. Optimum MK, GGBFS and activator solution ratios were investigated, and the compressive strength of non-heat-cured 28-day GMs reached 55 MPa. Analysis of GMs using scanning electron microscopy (SEM), energy-dispersive X-ray spectrophotometry (EDX) and X-ray powder diffraction (XRD) revealed alumino-silicate formation, potassium from KOH solution and calcium from GGBFS. It showed that the grains containing high silica in the form of quartz crystals were found in the gel formation. The strength and durability of MK- and GGBFS-based GMs exposed to freeze–thawing, a high temperature, wear loss, magnesium sulfate (MgSO4), sodium sulfate (Na2SO4) and HCl solutions were found to be sufficient.

Cr(VI) removal performance from wastewater by microflora isolated from tannery effluents in a semi-arid environment: a SEM, EDX, FTIR and zeta potential study.

Hexavalent chromium removal from the environment remains a crucial worldwide challenge. To address this issue, microbiological approaches are amongst the straightforward strategies that rely mainly on the bacteria's and fungi's survival mechanisms upon exposure to toxic metals, such as reduction, efflux system, uptake, and biosorption. In this work, scanning electron microscopy, energy-dispersive X-ray spectrophotometry, Fourier transform infrared spectroscopy, and zeta potential measurements were used to investigate the ability of chromium adsorption by Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp., and Candida maltosa strains isolated from tannery wastewater. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy revealed alterations in the cells treated with hexavalent chromium. When exposed to 50 mg/L Cr6+, Bacillus licheniformis and Candida maltosa cells become rough, extracellular secretions are reduced in Bacillus megaterium, and Byssochlamys sp. cells are tightly bound and exhibit the greatest Cr weight percentage. In-depth analysis of Fourier transform infrared spectra of control and Cr-treated cells unveiled Cr-microbial interactions involving proteins, lipids, amino acids, and carbohydrates. These findings were supported by zeta potential measurements highlighting significant variations in charge after treatment with Cr(VI) with an adsorption limit of 100 mg/L Cr6+ for all the strains. Byssochlamys sp. showed the best performance in Cr adsorption, making it the most promising candidate for treating Cr-laden wastewater.

A Comparative Study of Four different Contemporary NiTi Rotary Endodontic Files by Metallurgical and Mechanical Analysis with Energy-dispersive X-ray Spectrophotometry with FE-SEM and Cyclic Fatigue Resistance Evaluation

A Comparative Study of Four different Contemporary NiTi Rotary Endodontic Files by Metallurgical and Mechanical Analysis with Energy-dispersive X-ray Spectrophotometry with FE-SEM and Cyclic Fatigue Resistance Evaluation

A Comparative Evaluation of the Radiopacity of Contemporary Restorative CAD/CAM Blocks Using Digital Radiography Based on the Impact of Material Composition

Purpose The main purpose of this study was to assess the radiopacity of contemporary restorative computer-aided design (CAD)/computer-aided manufacturing (CAM) materials and the impact of material composition as measured by energy-dispersive X-ray spectrophotometry (EDX) on radiopacity. Materials and Methods Ten specimens of six CAD/CAM materials with 1 mm thickness were produced and then digitally radiographed with an aluminum (Al) step-wedge (SW) and 1 mm thick tooth slice. The specimen mean gray values (MGVs) were recorded in pixels and compared to an Al-SW, dentin, and enamel of equal thickness. For the elementary analysis of the composition of the materials, EDX was performed. Results The recorded MGVs ranged between 21.20 ± 4.94 and 238.5 ± 13.61 pixels. Materials were sorted according to the MGVs descendingly, Prettau, Vita Suprinity, Vita Enamic, Shofu, Pekkton, and BioHPP. Prettau and Vita Suprinity had significantly higher MGV than dentin and 1 mm thick Al. In comparison, Vita Enamic had a slightly higher value than dentin and 1 mm thick Al. Although Pekkton and BioHPP had MGV significantly lower than dentin and 1 mm thick Al, Shofu had a significantly lower value than dentin and nonsignificantly lower than 1 mm thick Al (p < 0.05). According to EDX analysis, the examined materials contained several components in varying quantities of radiopacity. Conclusions The radiopacity of only three studied materials exceeded the International Organization for Standardization's minimum standards (ISO).

The acid-resistance potential of arginine-fluoride varnish treated enamel

The study objective was to examine the acid-resistance potential of enamel carious lesions treated with arginine (Arg)-sodium fluoride (NaF) varnishes using nano-mechanical testing and chemical mapping. L-arginine (at 1%, 2%, & 4%) was incorporated in 5% NaF varnish. The experimental/control groups were: 1% Arg-NaF, 2% Arg-NaF, 4% Arg-NaF, NaF, and no treatment. Enamel specimen blocks were subjected to incipient carious lesion formation. After treatment, the specimens underwent chemical pH-cycling for 8-days and acid challenge for 2 h. The specimens were characterised for surface nano-hardness (SNH) and calcium/phosphate content of the treated lesions to determine enamel solubility reduction (ESR). Post-acid challenge, X-ray diffraction crystallography (XRD), and energy dispersive X-ray spectrophotometry (EDX) were performed. The SNH for 2%/4% Arg-NaF demonstrated a higher resistance to acid challenge with significantly higher SNH recovery than NaF varnish (p<0.05). The ESR potential of 2%/4% Arg-NaF varnish was significantly higher than NaF varnish (p<0.05). The XRD crystalline phases demonstrated that 2%/4% Arg-NaF had intense hydroxyapatite peaks discerning its increased potential to resist demineralization than NaF varnish. The EDX results showed that 2%/4% Arg-NaF demonstrated Ca/P ratio closer to hydroxyapatite (~1.67) post-acid challenge. Incorporating 2%/4% L-arginine in a 5% NaF varnish enhances the acid-resistance potential of NaF varnish.

Elemental composition and physical characteristics of the massive meteorite of the Saudi empty quarter

The meteorite found in the Empty Quarter of Kingdom of Saudi Arabia (KSA) is the largest meteorite found in the KSA and has the shape of an irregular ellipsoid with semi-axes of 0.65 m,0.38 m, and0.27 m; a density of 6400 kg/m3; and a mass of 2550 kg. It is a massive piece belonging to the category of iron–nickel meteorites, which is contained in only 5% of the total showers. The present report is on the Elemental composition and physical characteristics of the massive meteorite of the saudi empty quarter employing with laser-induced break down spectroscopy (LIBS), X-ray fluorescence (XRF), scanning electron microscope (SEM), x-ray diffraction (XRD) and energy-dispersive x-ray spectrophotometry (EDX).Present study has indicated that the meteorite is composed of about 5% Ni, 91% Fe, 1.51% P, 0.3% Co, and a host of other elements, most of them appeared as oxides. The measured density of the meteorite is 6400 kg/m3 and it is confirmed by the micro-hardness test that the meteorite is porous (approximately about 19%). Based on our investigation, it is very likely that this meteorite would have “escaped” from the belt around Mars and Jupiter and is unlikely from the moon or elsewhere. This could be the first such study, employing the advanced instruments mentioned above regarding massive Saudi meteorite.

Lanthanum hydroxide: a highly efficient and selective adsorbent for arsenate removal from aqueous solution.

In the present work, a lanthanum hydroxide adsorbent was prepared by a simple precipitation process, and its arsenic removal performances and adsorption mechanisms were investigated by batch experiments and various techniques including field emission scanning electron microscopy with energy-dispersive X-ray spectrophotometry (FESEM-EDX), Brunauer-Emmett-Teller (BET) analysis, powder X-ray diffraction (p-XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The influence of pH on arsenic removal showed that the lanthanum hydroxide adsorbent can effectively remove As(V) from solution, whereas the As(III) removal was very low, indicating that the lanthanum hydroxide adsorbent can selectively remove As(V) but not As(III). The isotherm study showed that the maximum adsorption capacities of As(V) at pH 5.0 and 9.0 were 299.4 and 192.3 mg/g, respectively, much higher than those of the widely used ferrihydrite. Significant interference on As(V) removal was caused by the presence of phosphate and natural organic acids (NOAs), such as citric acid. Powder XRD, FTIR, and XPS analysis showed that the lanthanum hydroxide was almost transformed into lanthanum arsenate after As(V) adsorption at pH 4.0, while a portion of lanthanum hydroxide remained after As(V) adsorption at pH 6.0 and 9.0. Furthermore, ligand exchange between the hydroxyl groups of the adsorbent and As(V) and the formation of inner-sphere surface complexes could play a central role in arsenic removal which needs further investigation.

A study on the effects of varying concentrations on the properties of ytterbium-doped cobalt selenide thin films

Cobalt selenide thin films were synthesized and doped with ytterbium via electrodeposition technique. The morphological, structural, elemental and optical properties were obtained using scanning electron microscopy (SEM), x-ray diffractometry (XRD), energy dispersive x-ray spectrophotometry (EDX) and ultraviolet–visible spectroscopy (UV–vis) respectively. SEM results revealed round-like shaped nanograins while a hexagonal crystal structure was obtained from the XRD results. EDX spectrum revealed the deposition of the basic elements in the films deposited. Optical analysis showed high transmittance and reduced band gap energies of the cobalt selenide films upon doping with ytterbium. The obtained films serve as potential materials for optical and photonic devices.

MWCNTs/ZnO Nanofibers Fabrication, Properties and Applications

Electrospun MWCNTs nanofibers (CNF1, CNF2 and CNF3) with different concentrations of MWCNTs (0.3, 1.5, 2 wt%), respectively, were deposited on Aluminum foil substrates. Also,Zinc AcetatedihydrateZn(CH3COO)2.2H2O (ZNF) and MWCNTs/zinc acetate (CZNF)nanofiberswere deposited on Aluminum foil substratesand annealed in the presence of oxygen at 400 oC. The resultant fibers were characterized using X-ray differaction (XRD), scanning electron microscope with energy dispersive X-Ray spectrophotometry (SEM,EDX), Fourier transform infrared (FTIR). SEM,EDX and FTIR exhibited a total decomposition of the organic precursor after calcination and formation of zinc oxide (ZONF and CZONF). The mean fiber diameter was found to be increased with increasing MWCNTs concentration and ranged 490-767 nm. XRD patterns indicated that ZnO was corundum with the hexagonal wurtzite structure. The crystallite size of ZONF and CZONF were determined by shurrer equation to be26 and 29.7 nm, respectively. The optical analysis indicated that the percentage transmittance increased after calcination.The band gap for the electrospun fibers before and after calcination was calculated. CZONF nanofibers have elec­trical properties similar to those of semiconductors. The testedcompounds CNF2, CNF3, CZNF and CZONF exhibited different activities against the bacteriaand yeast pathogen Candidaalbicans. CZNF compound is the most active against the bacteria and yeast pathogen. So, these compounds can be used as food packaging.&#x0D;

Experimental study of influence of composition on radiopacity of fiber post materials.

This experimental study aims to evaluate the radiopacity of various fiber post materials and to determine the effects of material composition as analyzed by energy-dispersive X-ray spectrophotometry (EDS; EDAX Team Software; EDAX, Inc., Mahwah, NJ) on radiopacity. Five specimens of seven fiber post materials with 2-mm thickness were prepared and digital radiographs were taken with an aluminum stepwedge (SW) and 2-mm-thick tooth slice. The mean gray values (MGVs) of specimens were measured using the histogram function of a computer graphics program (Adobe Photoshop CS6; Adobe System, Inc., San Jose, CA). The MGVs of fiber post materials were compared with an aluminum SW and dentin of equal thickness. The fiber post specimens were examined by scanning electron microscopy and EDS analysis performed for the elementary analysis of material composition. The MGVs of fiber posts ranged between 83.67 ± 3.64 and 57.80 ± 7.08 pixels. Materials were sorted in descending order of MGV as follows: Reforpost, Carbopost, D.T. Light-Post, Easypost, Glassix Radiopaque, Dentolic Glass Fiber Post, and RelyX Fiber Post. All fiber posts demonstrated significantly higher radiopacity values than 2-mm-thick aluminum (p < .05). EDS analysis results indicated that the evaluated fiber posts included various elements for radiopacity in different ratios. All tested fiber post materials showed radiopacity values above the minimum recommendations of the International Organization for Standardization. EDS analysis results indicated that each manufacturer used different compositions of elements like zirconium, barium, titanium, and iron for achieving radiopacity in materials.

Atomic force microscopy and energy dispersive X-ray spectrophotometry analysis of reciprocating and continuous rotary nickel-titanium instruments following root canal retreatment.

The aim was to examine the effect of retreatment process on the surface roughness and nickel titanium (NiTi) composition of ProTaper Universal Retreatment (PTUR; consists of 3 files; D1, D2, D3) and WaveOne Gold (WOG) (primary) instruments. Twenty extracted mandibular molar teeth with severe curved (30-40°) mesial roots were selected and divided into two groups (n = 10) based on the instrument used for the removal of the root canal filling. Before and after using the instruments in two canals, they were subjected to atomic force microscopy (AFM) and energy dispersive X-ray spectrophotometry (EDX) analysis. The EDX analysis data and roughness average (Ra) and root mean square (RMS) values were analyzed statistically using a one-way analysis of variance and post hoc Tukey's test at the 5% significant level. There was no significant difference between the new and used D1 and D2 PTUR and WOG instruments in terms of the Ni composition (p > .05). The Ti contents of the used D2 and D3 PTUR instruments were lower those of the new instruments (p < .05). In both new and used instruments, PTUR and WOG have no difference in terms of Ra and RMS values. (p > .05). The Ra and RMS values of the PTUR and WOG systems significantly increased after removal of the root canal filling (p < .05). The use of PTUR and WOG instruments for removal of root canal filling in severely curved root canals affected the surface topography of the files. The NiTi composition of the WOG instruments was unaffected by the retreatment process.

Effects of the Citric Acid Addition on the Morphology, Surface Area, and Photocatalytic Activity of LaFeO3 Nanoparticles Prepared by Glucose-Based Gel Combustion Methods

In this paper, the synthesis of LaFeO3 based on the gel combustion method has been improved by using citric acid (CA) as a secondary chelating agent on glucose. The synthesized samples were calcined at 600 °C and further characterized using X-ray diffraction (XRD), Fourier transform infrared, field-emission scanning electron microscopy (FESEM), scanning electron microscopy, energy-dispersive X-ray spectrophotometry, N2 adsorption–desorption analyses, thermogravimetric analysis, and UV–vis–near-IR spectroscopy. The XRD data revealed that the pure orthorhombic perovskite phase LaFeO3 was obtained when CA was added on glucose. From FESEM and Brunauer–Emmett–Teller analysis, LaFeO3 synthesized using the addition of CA on glucose potentially showed well-uniform spherical particles and a high specific surface area of 40.77 m2/g with a particle size of 70 nm compared to glucose, which only showed 15.68 m2/g with a particle size of 100–300 nm. The photocatalytic activity of LaFeO3 was evaluated by the degradation...

Preparation and Characterization of Chemically-Modified Biomaterials and Their Application as Adsorbents of Penicillin G

The prevalence of antibiotics in water creates microbial resistance and has a negative impact on the ecosystem. Biomaterials such as spent tea leaves are rich in functional groups and are suitable for chemical modification for diverse applications. This research proposes the use of spent tea leaves of chamomile (CM), green tea (GT), and peppermint (PM) as structural scaffolds for the incorporation of carboxyl, sulfonyl, and thiol groups to improve the adsorption of Penicillin G (Pe). Adsorbents characterization reported a higher number of acidic functional groups, mainly in thiolated products. Scanning electron microscopy (SEM) analysis showed changes on the surfaces of the adsorbents due to reaction conditions, with a stronger effect on thiolated and sulfonated adsorbents. Elemental analysis by Energy dispersive X-ray spectrophotometry (EDS) corroborated the chemical modification by the presence of sulfur atoms and the increase in oxygen/carbon ratios. Batch experiments at different pH shows a strong pH-dependence with a high adsorption at pH 8 for all the adsorbents. The adsorption follows the trend CMs &gt; GTs &gt; PMs. Thiolation and sulfonation reported higher adsorptions, which is most likely due to the sulfur bridge formation, reaching adsorption percentages of 25%. These results create a new mindset in the use of spent tea leaves and their chemical modifications for the bioremediation of antibiotics.

Synthesis of self-assembled mesoporous 3D In2O3 hierarchical micro flowers composed of nanosheets and their electrochemical properties.

This report describes the methodology for the fabrication of mesoporous In2O3 microflowers by hydrothermal and calcination procedures in which In(OH)3/In2S3 acts as an intermediate. Both In2O3 and its precursor were analyzed with scanning electron microscopy, energy dispersive X-ray spectrophotometry, transmission electron microscopy and powder X-ray diffraction. BET surface area, pore size and pore volume analyses were also carried out. Electron microscopy images clearly evidence the self-assembly of 2D nanosheets into the micro flower structure. The mechanism of self-assembly and calcination is reported. Electrochemical properties of the synthesized In2O3 micro flowers were studied.

Silk fibroin/hydroxyapatite composite hydrogel induced by gamma-ray irradiation for bone tissue engineering

BackgroundIn this study, silk fibroin (SF) composite hydrogels containing hydroxyapatite (HAP) nanoparticles (NPs) for bone tissue engineering were fabricated using gamma-ray (γ-ray) irradiation treatment. During the irradiation, the HAP dispersed SF solution was changed to the chemically crosslinked SF hydrogel.MethodsDistribution of HAP NPs in the SF hydrogel was examined by SEM imagery and energy dispersive X-ray spectrophotometry, and the crystalline structure of SF composite hydrogels was also confirmed by X-ray diffractometry. An optimum preparation condition of the SF/HAP composite hydrogels was determined with various HAP contents. For evaluation of the osteogenic differentiation of human mesenchymal stem cells (hMSCs), alkaline phosphatase activity (ALP), HAP nucleation in SBF and in vitro calcium accumulation were measured.ResultsThe results revealed that compared with the pure SF hydrogels, the SF/HAP composite hydrogels improved osteogenic differentiation.ConclusionThis paper demonstrates the great potential of the SF/HAP composite hydrogels in terms of the production of the bone tissue engineering scaffolds for which osteogenesis is required.

Energy-dispersive x-ray spectrophotometry(EDX) analysis of metalceramic bonds in cobalt-chromium alloys for the fabrication of fix dental restorations

Background/Aim. The aim of this research was to determine and quantify changes in the composition of metal-ceramic bond in the base dental alloys submitted to the procedure of multiple casting. Recusing (recycling) of dental alloys is performed very often in the fabrication of fix dental restorations, however, paying no attention to functional durability of the made crown or bridge. Quantitative and qualitative analyses of metal-ceramic bonds should show if recycling of alloys could be justified, that is to estimate the influence of recasting the alloy upon the chemical composition of its bond to ceramics. Methods. This experimental study was performed on Wirebond-C alloy cast multiple times through 12 generations of recycling. A total of 24 samples were evaluated - per six samples in each group as follows: the group A - the first cast, the group B - the third recycling, the group C - the sixth recycling, and the group D - 12th recycling. An Inca X-Sight (Oxford Instruments) and a SEMJEOL microscope type JSM 6460 LV (Tokio, Japan) were used for EDX analysis of the prepared sanples under the following conditions: electron beam frequency of 20,000 impules per second, beam voltage of 10 kV acquisition time of 250 sec, analysed energy range of X-rays energy 0-10 KeV Quantitive EDX analysis of metal ceramic interface was performed by the use of INCA software (Oxford Instruments) in regard to applicable metal and non-metal standards. Results. Each of the metal components of the alloy was decreasing permanently in the composition of metal-ceramic bond with the increase of the number of casting, while ceramic elements were increasing their presence. Individual analysis showed that multiple casting of Wirobond-C alloy reduced a portion of cerium in the metal-ceramic interface to the greatest extent. There was a significant difference between the groups in the composition of metal-ceramic bond after the first casting and the sixth recycling of the alloy (p < 0.001; p < 0.002; t- test independent sample). Conclusion. Recasting of the base cobalt-chromium alloys could not be recommended due to the change in the composition of metal-ceramic interface. Recycling of these alloys brings about significant changes in the metal-ceramic interface with the possible consequences such are weakening of the bond and damage of ceramic during mastication.

The Gboko Limestone, Yandev, Benue State, Nigeria: Geology, Geochemistry and Industrial Potentials

The Cretaceous shallow marine Gboko limestone, Yandev, Nigeria is a component of the sedimentary fill of the 800 km NE-SW trending Benue Trough, Nigeria. The limestone is made up of thin bedded to massive limestone beds interspersed with laminated grey shale having foraminifera as the dominant fossil. The limestone has both mud supported and grain supported texture, and micrites constitute about 75% of the limestone. Bulk chemical composition analysis of the limestone reveals average CaCO3 of 92.41% and a range of 77.50% - 99.00%. Mineralogical impurities include quartz, dolomite, pyrrhotite, fluorapatite etc. Trace elements concentration analysis was carried out using Energy Dispersive X-ray (EDXRF) spectrophotometry and showed the following trace elements: Mn (841.3 ppm), Sr (444.6 ppm), Fe (470 ppm), Zn (114.6 ppm) and Pb (116.4 ppm). Calcining the limestone in a laboratory muffle furnace at 1050°C for 90 minutes produced a compact, soft burnt porous and reactive lime that does not crumble into fines. The lime so produced neither meets the requirements of the Steel Making Shop (SMS) of the Ajaokuta Steel Plant nor could it be used in the growing sugar refining industry in Nigeria. It can however be used in the food and the food by-products industry, environmental, agricultural and petroleum industries etc. The raw stone remains a major source of raw materials for cement manufacture for the ever expanding building industry.

Effect of Zirconia and Alumina Fillers on the Microstructure and Mechanical Strength of Dental Glass Ionomer Cements.

Background:Glass-ionomer cements perform a protective effect on the dentin-pulp complex considering the F ions release and chemical bonding to the dental structures. On the other hand, those materials have poor physic-mechanical properties in comparison with the restorative resin composite. The main aim of this work was to evaluate the influence of zirconia and/or alumina fillers on the microstructure and strength of a resin modified glass-ionomer cement after thermal cycling. Methods:An in vitro experimental study was carried out on 9 groups (n = 10) of cylindrical samples (6 x 4 mm) made from resin modified glass-ionomer (Vitremer, 3M, USA) with different contents of alumina and/or zirconia fillers. A nano-hybrid resin composite was tested as a control group. Samples were mechanically characterized by axial compressive tests and electron scanning microscopy (SEM) coupled to energy dispersive X-ray spectrophotometry (EDS), before and after thermal cycling. Thermal cycling procedures were performed at 3000, 6000 and 10000 cycles in Fusayama´s artificial saliva at 5 and 60 oC.Results:An improvement of compressive strength was noticed on glass-ionomer reinforced with alumina fillers in comparison with the commercial glass ionomer. SEM images revealed the morphology and distribution of alumina or zirconia in the microstructure of glass-ionomers. Also, defects such as cracks and pores were detected on the glass-ionomer cements. The materials tested were not affected by thermal cycling in artificial saliva.Conclusion: Addition of inorganic particles at nano-scale such as alumina can increase the mechanical properties of glass-ionomer cements. However, the presence of cracks and pores present in glass-ionomer can negatively affect the mechanical properties of the material because they are areas of stress concentration.

Scanning electron microscopy with energy dispersive X-ray spectrophotometry analysis of reciprocating and continuous rotary nickel-titanium instruments following root canal retreatment.

This study aimed to evaluate superficial defects and the composition of Reciproc R25 and ProTaper Retreatment file systems (Dentsply Maillefer, Ballaigues, Switzerland) used for retreatment. A total of 100 maxillary incisor teeth were randomly divided into the following two groups: Reciproc R25 (n = 25) and ProTaper Retreatment instrument (n = 75) groups. The nickel-titanium (Ni-Ti) compositions of the files before and after use were analyzed using energy dispersive X-ray spectrophotometry (EDX). Chi-square, Mann-Whitney U, and Kruskal-Wallis tests were used to analyze the data. ProTaper Retreatment instrument group showed a significantly higher number of defects than the Reciproc group (P < 0.05). No instrument fracture was detected. The presence of debris was observed in both groups before use, although the level was significantly higher in the ProTaper Retreatment group, which consisted of metals (P < 0.05). There was no significant difference between new and used instruments with regard to Ni-Ti composition (P < 0.05). EDX analysis showed that both the Reciproc and ProTaper Retreatment instruments had a Ni-Ti composition that was within the standards specified by the American Society of Testing and Materials. This study confirmed the use of both the Reciproc R25 file and ProTaper Retreatment file system for root canal filling removal in straight root canals as a safe procedure. (J Oral Sci 58, 401-406, 2016).

Ionic Liquid in Thin-Layer Chromatography of Anionic Surfactants: Selective Separation of Sodium Deoxycholate and Identification in Commercial Products

AbstractThe coupling of a silica static flat phase impregnated with an ionic liquid (1-methylimidazolium chloride) as stationary phase with 2-methyltetrahydrofuran an alternative green solvent of tetrahydrofuran as mobile phase has been very successful for a selective separation of sodium deoxycholate from other commonly used anionic surfactants. The proposed thin-layer chromatographic system is capable to analytically discriminate among the anionic surfactants in relation to their migration behaviour on an ionic liquid loaded silica layer. The surface structure and chemical composition of silica gel G modified by impregnation were examined with the aid of scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometry (EDX) respectively. Effects of concentration level of 1-methylimidazolium chloride as impregnant and its substitution by other ionic liquids (1,2,3-trimethylimidazolium methyl sulphate, 1-ethyl-3-methylimidazolium tetrafluoroborate) were also studied to decide the optimum experimental conditions for better separation possibilities. Chromatographic parameters such as ΔRF, the separation factor (α) and the resolution (RS) for the separation and limit of detection were calculated. The developed method has been usefully applied for the identification of sodium deoxycholate and sodium lauryl sulphate in formulated and commercially available products (Colgate toothpaste and Head &amp; Shoulder Shampoo).