Plasma Atomic Emission Spectrometric Analysis Research Articles

Selecting an Acid Mixture for Microwave Digestion of Diverse Steel Samples in Inductively Coupled Plasma Atomic Emission Spectrometric Analysis of Boron, Aluminum, Silicon, Phosphorous, and Alloyed Elements

Selecting an Acid Mixture for Microwave Digestion of Diverse Steel Samples in Inductively Coupled Plasma Atomic Emission Spectrometric Analysis of Boron, Aluminum, Silicon, Phosphorous, and Alloyed Elements

Ionic Liquid-Modified Porous Organic Polymers as Efficient Metallocene Catalyst Supports

Porous organic polymers (POPs) are widely used in various areas such as adsorption, separation and catalysis. In the present work, ionic liquid-modified porous organic polymers (IL-POPs) synthesized by dispersion polymerization were applied to immobilize metallocene catalysts for olefin polymerization. The prepared IL-POPs were characterized by Fourier transform infrared spectrometer (FT-IR), nitrogen sorption porosimetry, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometer (ICP) and scanning electron microscope (SEM) analysis. The IL-POPs obtained pores with surface specific area (SSA) ranging from 16.9 m2/g to 561.8 m2/g, and total pore volume (TPV) ranging from 0.08 cm3/g to 0.71 cm3/g. The supported catalysts Zr/MAO@IL-POPs exhibit great activity (3700 kg PE/mol·Zr·bar·h) in ethylene polymerization, and the GPC-IR results show that the polyethylene has narrow molecular weight distribution (2.2 to 2.8). The DSC results show that the melting point of prepared polyethylene was as high as 138 °C, and the TREF analysis results indicate that they have similar chemical composition distribution with elution temperature at 100.5–100.7 °C.

Investigation of metalloporphyrin compound in maltenes of duri crude oil

Metalloporphyrin is one of the compounds that could potentially cause deactivation of catalysts in the process of catalytic cracking and hydrotreating. Knowledge of the structure of metalloporphyrin can be used as the basic information in overcoming the problem of catalyst poisoning. This work is performed to identify metalloporphyrins in the maltenes fraction of Duri crude oil. The low content of asphaltenes in Duri crude oil with a fractional weight of 0.79 %, allows a high level of metalloporphyrin in the fraction of maltenes which has a fractional weight of 82.73 %. Metalloporphyrin in the maltenes derivate fraction, saturates, aromatics, and resin were separated using column chromatography. Saturates, aromatics and resins have fractional weight of 49.75; 34.92; and 15.33 %, respectively. Only resin contained metalloporphyrin based on the analysis of UV-Vis spectrophotometer and Fourier-transform infrared spectroscopy (FT-IR), thus metalloporphyrins in resin was further separated into fractions by column chromatography. The result of UV-Vis spectrophotometer analysis for resin separation showed an absorbance peak of metalloporphyrin at 480–700 nm, while FT-IR analysis showed the presence of pyrrole group as porphyrin base framework with vibrational region at 400–1100 cm−1 The results of micro plasma-atomic emission spectrometer (MP-AES) analysis showed the presence of Fe, Ni, and V metals content. The liquid chromatography-mass spectrometer (LC-MS) analysis showed the molecular structure of the obtained compound was C33H34N4VO2. According to the results, metalloporphyrins presented in the maltenes fraction of Duri crude oil was vanadyl porphyrin.

Solid Phase Extraction and Flame Atomic Absorption Determination of Cadmium in Water Samples

A new sensitive and selective method including solid phase preconcentration and next determination of trace amounts of Cd(II) by flame atomic absorption spectroscopy in water samples was developed. Cadion was coated on carbon active powder and used as a solid phase sorbent. Detection limit for extraction of 2000 mL aqueous solution is 0.35 μg·L–1. The relative standard deviations for concentrations 2.5 and 15 μg·L–1 with preconcentration factor 200, 0.4 and 0.2% (n = 3) were obtained, respectively. The calibration curve is linear in the range of 1.5–15 μg·L–1. The accuracy of the method was evaluated and confirmed by the inductively coupled plasma atomic emission spectrometric analysis. Method was applied for the determination of cadmium in well water.

Effect of Tungsten Addition on Nickel-Based Catalyst for Combined Steam and CO2 Reforming of Methane.

In this study, we investigated the effect of tungsten addition on Ni-based catalyst in methane steam-CO₂ reforming. All the catalysts were prepared by the co-impregnation method with varied tungsten loading. The as-prepared catalysts were characterized by inductively coupled plasma atomic emission spectrometer, X-ray diffraction, temperature-programmed reduction and thermogravimetric analysis. The tungsten-loaded catalyst showed improved coke resistance and CO₂ reactivity by the conducting activity test under fixed conditions.

The visible-light-driven type III heterojunction H3PW12O40/TiO2-In2S3: A photocatalysis composite with enhanced photocatalytic activity

H3PW12O40/TiO2-In2S3, a visible-light-driven Type III photocatalysis composite heterojunction, is synthesized by typical sol-gel method. The X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometer (ICP-AES) and energy dispersive X-ray spectra (EDS) analysis show that HPW which is anchored to the surface of TiO2-In2S3 makes the crystallite sizes of HPW/TiO2-In2S3 reduce to 9.7 nm. X-ray photoelectron spectroscopy (XPS) analysis confirm that HPW acts as the bridge assisting in the transfer of electronics from TiO2 to In2S3 in H3PW12O40/TiO2-In2S3. The optical properties of synthesized composites are investigated by UV–Vis diffused reflection spectra (UV–Vis DRS) and photoluminescence (PL) spectra. The lattice defects of TiO2 lead to the existence of oxygen-vacancies and impurity energy levels which make TiO2 respond to visible light. And the type-III heterojunction restrains the recombination of photo-generated carriers effectively. Under visible light irradiation (λ = 400 nm), H3PW12O40/TiO2-In2S3 displays higher photocatalytic degradation activity of imidacloprid (82.7%), comparing with H3PW12O40/TiO2 (26.7%), TiO2-In2S3 (20.6%) and TiO2 (16.0%). The pseudo-first-order degradation rate constant of HPW/TiO2-In2S3 is 6, 7 and 13 times higher than that of HPW/TiO2, TiO2-In2S3 and TiO2, respectively. Moreover, the photogenerated holes and ·OH radicals are proved as the main active species in degradation process.

Removal process of nickel(II) by using dodecyl sulfate intercalated calcium aluminum layered double hydroxide

Calcium aluminum layered double hydroxides (LDH) modified with sodium dodecyl sulfate (SDS) (Ca/Al-DS LDH) was prepared to investigate the unique removal mechanism of metal cations by organic calcium-contained LDHs. The as-prepared sample was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma atomic emission spectrometer (ICP-AES) and elemental analysis (EA). Ni(II) was selected as the target metal cation and its removal kinetics could be well described by the pseudo-second-order kinetic model (R2=0.990). The maximum removal capacity of Ni(II) reached 2.45mol/g at the LDH dosage of 0.5gL−1. The XRD and element analysis results indicate that a new Ni/Al-DS LDH phase and CaCO3 were formed as well as a portion of Ca/Al-DS LDH remained in the final products after the removal process. Therefore, the removal of Ni(II) was contributed to the surface complexation, isomorphic substitution and sorption on the CaCO3. The pillared interlayer organic anions might help to keep the layered structure of LDH. This study revealed the multi-interaction mechanism of metal ions with Ca/Al LDH and proposed a novel strategy to generate organic intercalated LDHs by isomorphic substitution.

The Key Gold: Enhanced Platinum Catalysis for the Selective Hydrogenation of α,β-Unsaturated Ketone

AuPt alloy nanoparticles (NPs) were facilely synthesized with oleylamine as the stabilizing ligand and characterized by high-resolution transmission electron microscopy, powder X-ray diffraction, inductively coupled plasma-atomic emission spectrometer analysis, and so on. In addition, the AuPt alloys supported by the nano CeO2 exhibit high selectivity and efficiency in hydrogenation of benzylidene acetone under ambient temperature and pressure. By analyzing the catalytic performance over the NPs with different Au:Pt compositions, we found that the TONPt values (based on the number of Pt atoms) vary in the same trend with the change of conversion. Despite that gold itself shows no catalytic activity, the improved conversion and TONPt with the alloy catalysts clearly show the promotion effect of gold on the catalytic activity of the platinum. The inactive metal significantly improves the catalytic activity of active metal, which shows that the AuPt alloy exhibits an interesting synergistic effect.

Electrochemical extraction and separation of praseodymium and erbium on reactive magnesium electrode in molten salts

The electrochemical behaviors of Pr(III) and Er(III) in LiCl-KCl melts were studied on inert tungsten and reactive magnesium electrodes by cyclic voltammetry, square wave voltammetry, and open-circuit chronopotentiometry at 823 K. On a W electrode, the reduction of Pr(III) and Er(III) were found to be through a one-step process: Pr(III) + 3 e− → Pr, Er(III) + 3e − → Er. On a Mg electrode, the reduction potentials of Pr(III)/Pr and Er(III)/Er were observed at more positive potential values than those on W electrode, due to the formation of Mg-Pr and Mg-Er intermetallic compounds when Pr(III) and Er(III) ions were reduced to Pr and Er metal and then react with the Mg substrate, respectively. The extraction of Pr(III) and Er(III) in LiCl-KCl melts were performed by galvanostatic electrolysis on Mg electrode, respectively. The Mg3Pr and Mg24Er5 intermetallic compounds were obtained, which characterized by X-ray diffraction (XRD) and scanning electron microscopy equipped with energy-dispersive spectrometry (SEM-EDS). In order to separate the Pr(III) and Er(III), potentiostatic electrolysis was performed at −1.9 V in LiCl-KCl-PrCl3-ErCl3 melts on a Mg electrode, only one Mg-Pr intermetallic compound, Mg12Pr, was found in the deposit. The separation efficiency was evaluated via inductively coupled plasma atomic emission spectrometer (ICP-AES) analysis at different electrolysis time during potentiostatic electrolysis at −1.9 V. The separation efficiency of Pr(III) was about 95.3 % from the mixture of PrCl3-ErCl3 in LiCl-KCl melts.

Evaluation of the flocculation and de-flocculation performance and mechanism of polymer flocculants

Understanding the interaction mechanism between polymeric flocculants and solid particles in two oppositely charged solutions: bentonite and calcium fluoride, is of great practical and fundamental importance. In this work, inorganic flocculants based on aluminum(III) or iron(III); cationic, anionic and non-ionic organic flocculants were used. The solution pH, which highly influenced the flocculation performance of the system, has been used as a function of turbidity removal, sediment volume and velocity. Results show that the flocculation of inorganic polymers does not depend on the zeta potential but on the solution pH, contrary for cationic and anionic polymers. Non-ionic polymer was independent on both. By varying the final pH of the heterogeneous solution formed of flocs-liquid, it was found for inorganic polymers, the optimum condition of pH < 3 to separate inorganic flocculant particles from flocs. Inductively coupled plasma atomic emission spectrometer and X-ray fluorescence analysis proved the reversibility of flocculation process by indicating the concentration of flocculant representative atom (Al or Fe) in the flocs and in the emerging solutions when the flocculation was optimized and the reversibility was effective. As results, weak forces were suggested as responsible for inorganic polymers flocculation where electrostatic interaction and hydrogen bonds may enroll the mechanism of organic flocculants.

Extraction of ytterbium via co-reduction of Al(III) and Yb(III) from LiCl–KCl melt on W electrode

Anhydrous ytterbium chloride was obtained via solid-phase reaction from Yb2O3 with AlCl3 as a chlorination agent. The electrochemical behavior of the chloridized Yb2O3 was investigated on W electrodes in LiCl–KCl and LiCl–KCl–AlCl3 melts by cyclic voltammetry and square wave voltammetry. The results showed that the reduction/reoxidation of Yb(III)/Yb(II) was reversible and controlled by diffusion. The signals related to the formation of two Al–Yb intermetallic compounds were detected in LiCl–KCl–AlCl3 melt. Potentiostatic electrolysis was carried out in LiCl–KCl–AlCl3–YbCl3 melt on W electrodes at 943 K at different potentials and Al3Yb, Al2Yb, AlLi and Al2Li3 phases were detected in deposits. Then, the extraction of ytterbium was performed. The currents evolution was recorded by square wave voltammetry and the extraction efficiency was evaluated via inductive coupled plasma atomic emission spectrometer analysis during electrolysis. The initial extraction rate is much higher than that at longer times. The extraction efficiency was about 98.0 % for Yb(III) after potentiostatic electrolysis for 60 h at −1.84 V in LiCl–KCl–AlCl3–YbCl3 melt.

Analytical and quantitative concentration of gunshot residues (Pb, Sb, Ba) to estimate entrance hole and shooting-distance using confocal laser microscopy and inductively coupled plasma atomic emission spectrometer analysis: An experimental study

The identification of gunshot residues (GSRs) on human body in firearm related fatalities may be essential for the evaluation of gunshot wounds and for the analysis of the shooting distance. The present study introduces the elemental analysis of the GSRs by inductively coupled plasma atomic emission spectrometer analysis (ICP-AES) performed on skin samples. ICP-AES was used to increase the accuracy of the analysis in gunshots fired from long and medium distance. In this experimental study, a series of 50 test shots have been performed in an open space with lateral wind protection. As target we used pig skin cut into 20cm×20cm squares. The firing distances were 0.2, 5, 50, 100 and 150cm. To exclude environmental contamination, each skin sample was carefully washed with deionized water and dried at room temperature in a closed box before the shooting test. We choose 9×21 and the 7.65mm calibers handguns, loaded with different ammunitions. At ICP-AES analysis a clearly decreasing trend in the quantity and the concentration of the different elements of GSR by increasing the firing distance for both the guns used in the test was evident for every portion of skin samples analyzed. The analytical results obtained by ICP-AES confirmed very high concentrations of Pb, Sb, and Ba in the close-range shots and low concentrations of these particles in the intermediate and distant shots. In particular, the concentration of Sb, Ba, and Pb was significantly different from loose values when the firing distance was 100–150cm for both the 9×21 and the 7.65mm calibers.

Molecular Properties and Extracellular Processing of the Lipase of Staphylococcus warneri M

Staphylococcus warneri M exhibited extracellular lipase activity. By zymogram analysis of extracellular proteins, multiple bands were detected and the profiles changed depending on the bacterial growth phase. N-terminal amino acid sequences of three bands (N1–N3) were determined. From the genome library of S. warneri M whole DNA, the gene-directing lipase activity (named gehC_WM) was cloned and characterized. The gehC_WMgene encoded a protein (GehC_WM), whose calculated molecular mass was 83.4 kDa, and the sequence was similar to the other staphylococcal lipases. Though two lipases have been known from S. warneri 863, GehC_WM differs from both of them, indicating that this enzyme is the third extracellular lipase of the S. warneri strain. The N-terminal sequences of the N1–N3 polypeptides completely coincided with the deduced amino acid sequences in GehC_WM. GehC_WM was predicted to be a prepro-protein. In vitro processing and protein sequencing suggested that pro-GehC_WM is possibly processed by extracellular glutamyl endopeptidase, PROM. Inductively coupled plasma-atomic emission spectrometer analysis showed that purified his-tagged mature GehC_WM possessed zinc ion. A gehC_WM knockout mutant was constructed by insertion of an erythromycin resistance gene into the gehC_WM. Zymogram and immunoblot analyses of the gehC_WMmutant indicated that GehC_WM was a major extracellular lipase of S. warneri M.

Synthesis, characterization, and catalytic performance of copper-containing SBA-15 in the phenol hydroxylation

A series of copper-containing SBA-15 samples were successfully synthesized via evaporation-induced self-assembly route. The resulting materials were characterized by X-ray diffraction (XRD), 29Si MAS NMR spectroscopy, transmission electron microscopy (TEM), N2 sorption, inductively coupling plasma-atomic emission spectrometer (ICP-AES), thermogravimetry, and differential thermal analysis (TG–DTA), Fourier-transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectra (UV–vis) and X-ray photoelectron spectroscopy (XPS). The results indicated that: (1) all the samples exhibited typical hexagonal arrangement of mesoporous structure; (2) copper ions could be incorporated into the framework of SBA-15; (3) the addition of urea in the hydrothermal stage efficiently reduced the leaching of copper and improved the thermal stability of the mesoporous materials. Catalytic performances of the obtained materials were evaluated in the hydroxylation of phenol with H2O2. The catalytic tests showed that the synthesized materials exhibited high activity for this reaction and copper ions in the framework were more active than copper species in the extra-framework position. The nitric acid treatment on the samples removed the bulk CuO species, which resulted in a dramatic increase in the catalytic activity.

Antiphotocorrosive photocatalysts containing CdS nanoparticles and exfoliated TiO2 nanosheets

Aimed at designing an efficient visible light active photocatalyst and suppressing the self-corrosion tendency of CdS nanoparticles, a novel composite consisting of CdS nanoparticles and exfoliated two-dimensional (2D) TiO2 nanosheets was successfully fabricated using a simple self-assembly process. The prepared samples were characterized using various techniques including x-ray diffraction, ultraviolet–visible absorption spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that the exfoliated 2D nanosheets played an important role as an ultrathin coating to suppress the photocorrosion of CdS nanoparticles, evidenced by inductively coupled plasma-atomic emission spectrometer analysis. The resultant CdS/TiO2 composites exhibited enhanced photocatalytic activity in the oxidation of Rhodamine B in water under visible light irradiation (λ &gt; 420 nm).

Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations

The Cu-B system was investigated via a hybrid approach of key experiment and thermodynamic modeling. Based on the critically assessed Cu-B phase diagram, seven crucial alloys were selected and prepared by arc melting the pure elements. An inductively coupled plasma-atomic emission spectrometric analysis was conducted to determine the compositions of the prepared alloys. The phase equilibria were determined by using x-ray diffraction, electron probe microanalysis, and differential thermal analysis. The temperature associated with the eutectic reaction, \( {\text{L}}\Leftrightarrow {\text{(B)}} + {\text{(Cu)}},\) was measured to be 1028 ± 2 °C. First-principles calculations indicate that the energy of inserting a B atom into the interstitial vacancy (Va) site of the lattice for Cu atoms is marginally lower than that of substituting for a Cu atom with a B atom. Consequently, the sublattice model (Cu)(B, Va) in which B atoms occupy the interstitial sites was employed for the fcc (Cu) phase rather than the model (Cu, B)(Va) in which B atoms substitute for Cu atoms. A thermodynamic modeling of the Cu-B system was then performed by considering the reliable literature data and the present experimental results. A good agreement between modeling and experiment was obtained.

Effect of Sigma Phase in Co-29Cr-6Mo Alloy on Corrosion and Mechanical Properties

Effect of the sigma (σ) phase in Co-29Cr-6Mo alloy on corrosion and mechanical behavior has been investigated. The area fraction of the σ phase varies depending on the aging time at 1023 K. The area fraction of the sigma phase increases with increasing aging time and reaches 0.6 % after aging at 1023 K for 21.6 ks. Inductively coupled plasma atomic emission spectrometer (ICP-AES) analysis revealed the quantity of released Co ion shows almost the same values regardless of different area fraction of the σ phase. In addition, plastic elongation and 0.2% proof strength exhibit almost the same values, although the alloys have different area fraction of the σ phase. These results suggest that a small amount of the σ phase (&lt;0.6%) hardly affect the corrosion and mechanical properties in the Co-29Cr-6Mo alloy.

On-line slurry formation and nebulization for inductively coupled plasma atomic emission spectrometry. Multi-element analysis of cocoa and coffee powder samples

A simple on-line slurry formation and direct nebulization system for inductively coupled plasma atomic emission spectrometric multi-element analysis was developed. A laboratory made micro-chamber with a magnetic-stirrer was used for on-line stable slurry formation in a dispersant solution of 0.5% v/v Triton X-100 and 1% v/v HNO3. A Babington-type nebulizer combined with cyclonic-type spray chamber was adopted for on-line slurry nebulization and atomization. All critical parameters were studied and optimized. The performance of the system was demonstrated for Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Ni, and Zn determination in cocoa and coffee powder samples. The recommended particle size was <70 μm and the slurry concentration was 0.6% m/v, while the working slurry concentration could be ranged from 0.3 to 3.3% m/v with proportional sensitivity. Excellent agreement was found between the standard addition calibration procedure and the calibration curves using simple aqueous standard solutions for almost all of the investigated elements. The reliability of the proposed method was confirmed by comparing it with FAAS and ETAAS wet digestion methods for the analysis of cocoa and coffee samples. No significant differences were observed between the two methods.

Evaluation of different calibration methods in inductively coupled plasma atomic emission spectrometric analysis of certified glass materials and archaeological glass specimens

An extended study of the effect of the calibration strategy followed in multi-element analysis of glass matrices by inductively coupled plasma atomic emission spectrometry (ICP-AES) is reported. The accuracy of the determination of two major (Ca, Na) and four minor constituents (Al, Fe, Mg, Ba) was evaluated by analyzing two certified reference glass materials (SRM 620 and SRM 621) by three different calibration methods, including multi-element and single-element standards. The effect of sample dilution and the presence of high concentrations of some major constituents was also investigated. Two-way analysis of variance was applied at a given level of confidence (95%) to evaluate the significance of these effects as sources of variation, while the slope of the calibration curves was used as a reliable criterion for the evaluation of the different calibration processes. The recoveries obtained from the two SRMs were also found. Finally, the three calibration methods were applied successfully in the analysis of archaeological glass fragments and glassy specimens from an excavated ancient oven.

Determination of Ru, Rh, Pd, Te, Mo and Zr in spent pressurized water reactor fuels by ion exchange and extraction chromatographic separations and inductively coupled plasma atomic emission spectrometric analysis

A study has been carried out on the quantitative analysis of Ru, Rh, Pd, Te, Mo and Zr, which are main components of undissolved materials dispersed in nitric acid dissolver solutions of spent pressurized water reactor (PWR) fuels, using inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution of the insoluble residues filtrated from the dissolver solutions by acid digestion bomb technique and the separation of Ru, Rh, Pd, Te, Mo and Zr from U and transuranous elements in the filtrate by ion exchange, and di(2-ethylhexyl) phosphoric acid (HDEHP) extraction chromatography were discussed in detail. The applicability and versatility of the proposed separation procedure combined with ICP-AES analysis were evaluated by chemically characterizing the spent PWR fuels with burnups from 36,000 to 39,000 MWd/MtU.