Optical Emission Spectroscopy Method Research Articles

A novel plasma optical emission spectroscopy method with neural network model for improving the accuracy of plasma diagnostics in low-temperature xenon plasma

A novel plasma optical emission spectroscopy method with neural network model for improving the accuracy of plasma diagnostics in low-temperature xenon plasma

Direct One-Stage Plasma Chemical Synthesis of Nanostructured Thin Films of the System β-Ga<sub>2</sub>O<sub>3</sub>-GaN of Different Composition

For the first time, nanostructured thin films of the β-Ga2O3−GaN system were obtained by plasma chemical deposition from the gas phase (PECVD) on c-sapphire substrates. High-purity metallic gallium, as well as high-purity gaseous nitrogen and oxygen were used as sources of macro components. The low-temperature nonequilibrium plasma of an inductively coupled HF (40.68 MHz) discharge at a reduced pressure (0.01 Torr) was the initiator of chemical transformations between the starting substances. A mixture of oxygen and nitrogen was used as a plasma-forming gas. The plasma chemical process was studied using the optical emission spectroscopy (OES) method. The obtained thin films of the β-Ga2O3−GaN system with a GaN phase content of 2 to 7% were characterized by various analytical methods.

Construction of Multi-Channel Radio Frequency Plasma Jet System in Atmospheric Pressure and the Diagnosis of Plasma Parameters and I-V Characteristics

In order to produce cold plasma at atmospheric pressure, a multi-channel RF, of (1, 2, 3, and 4 MHz) frequencies, plasma jet system is developed using argon as the working gas. This system consists of two parts, a multi-channel power supply (of a power of 100 W) and a plasma jet. A strong electric field is created that ionizes and excites argon ions. The I-V characteristics of the system and the electron temperature and density for different powers (20, 50, 70, and 80 W), gas flow rates (10, 20, 30, and 40 sccm) (standard centimeter cubic per minute) at different frequencies (1, 2, 3, and 4 MHz) are studied, using the optical emission spectroscopy method. This system can be used in medical applications and material treatment with high efficiency.

Development and Validation of an ICP‐OES Method to Determine Extractable and Leachable Metals in HDPE (Plastic) Pharmaceutical Packaging Material

ABSTRACTThe safety and effectiveness of pharmaceutical medicines depend heavily on extractables and leachables. Patients may be adversely affected by contaminants that enter drug products through packing materials. As a result, regulatory organizations like the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) have set standards and regulations for evaluating and managing extractables and leachables. Characterizing the packing materials, carrying out extraction experiments and checking the extracted solutions for contaminants are all parts of this research. As part of the process for approving new drugs, regulatory agencies make use of these data. In present work, an inductively coupled plasma optical emission spectroscopy (ICP‐OES) method is developed and validated for quantifying trace elements from a high‐density polyethylene (HDPE) packaging material. The approach delineated in accordance with United States Pharmacopoeia (USP) <661.1> and <661.2> for the comprehensive analysis of 16 metallic elements including aluminium, arsenic, cadmium, chromium, cobalt, lead, mercury, nickel, titanium, vanadium, zinc, zirconium, barium, manganese, calcium and tin is applicable for evaluating the efficacy of packaging materials. The method detection limits (MDLs) complied as per USP 39‐NF 34 <661.1> along with relative standard deviations (RSDs) obtained were ranging from 0.3% to 3.1% and recoveries of all elements spiked at two different trace levels in HDPE samples were within 97%–110%, providing sensitive, accurate and reproducible methodology.

Experimental Research on the Study of Мéntha Piperíta Makro- and Microelement Composition Growing in Goris, Syunik Region

The purpose of our work was to study the qualitative and quantitative composition of the mineral elements of peppermint (Méntha piperíta) leaves. The relevance of the study is revealed by the fact that, though some trace elements in low concentrations are necessary for plant growth, their excess can lead to plant death. This effect depends both on the nature of the element and on the type of plant. To achieve this goal, we used the method of optical emission spectroscopy with inductively coupled plasma on an Agilent 5110 ICP-OEC equipment. The object of research was the dried aerial part of peppermint (Méntha piperíta) growing in Goris region of Armenia. The content of 30 elements was determined, for five of which the biological absorption coefficient is greater than unity. This means that these elements accumulate in plants. These include strontium and molybdenum, which are toxic elements. Based on the data presented, it is certainly necessary to control the maximum permissible concentrations of molybdenum and strontium in peppermint (Méntha piperita) collections before using it in cooking and for the creation of medicinal products.

Application of ICP-OES for determination of mercury species in environmental samples

Direct determination of mercury species in real environmental samples is challenging due to their trace concentrations and low ionisation energy. In this investigation, a microwave-assisted and aqua regia digestion method is proposed for the analysis of trace inorganic mercury. Measurements were performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) method in soil, digestate and waste samples. The detection limits of the proposed method were found to be 0.03 and 0.115 mg/kg for mercury at 184.9 and 194.2 nm, respectively. The accuracy of the method with respect to the systematic and constant errors was confirmed by the analysis of certified reference material (CRM) (> 95 % recovery with < 15 % relative standard deviation RSD). The method was successfully applied for the determination of mercury in solid wastes listed in the Decree on Burdening of Soil with Waste Spreading and the Decree on the Treatment of Biodegradable Waste and the Use of Compost or Digestate in the Republic of Slovenia (Official Gazzette of the Republic of Slovenia, No. 34/08 and 61/11 and No 99/13, 56/15 and 56/18).

A novel state-resolved actinometry method to determine the nitrogen atom number density in the ground state and intra-shell excited states in low-pressure electron cyclotron resonance plasmas

The active-particle number density is a key parameter for plasma material processing, space propulsion, and plasma-assisted combustion. The traditional actinometry method focuses on measuring the density of the atoms in the ground state, but there is a lack of an effective optical emission spectroscopy method to measure intra-shell excited-state densities. The latter atoms have chemical selectivity and higher energy, and they can easily change the material morphology as well as the ionization and combustion paths. In this work, we present a novel state-resolved actinometry (SRA) method, supported by a krypton line-ratio method for the electron temperature and density, to measure the number densities of nitrogen atoms in the ground and intra-shell excited states. The SRA method is based on a collisional-radiative model, considering the kinetics of atomic nitrogen and krypton including their excited states. The densities measured by our method are compared with those obtained from a dissociative model in a miniature electron cyclotron resonance (ECR) plasma source. Furthermore, the saturation effect, in which the electron density remains constant due to the microwave propagation in an ECR plasma once the power reaches a certain value, is used to verify the electron density measured by the line-ratio method. An ionization balance model is also presented to examine the measured electron temperature. All the values obtained with the different methods are in good agreement with each other, and hence a set of verified rate coefficient data used in our method can be provided. A novel concept, the ‘excited-state system’, is presented to quickly build an optical diagnostic method based on the analysis of quantum number propensity and selection rules.

Characterization of a filamentary discharge ignited in a gliding arc plasmatron operated in nitrogen flow

A gliding arc plasmatron (GAP) is a promising warm plasma source for the use in gas conversion applications but lacks an understanding of the plasma dynamics. In this paper, the gliding arc plasma conditions of a GAP operated with nitrogen flow (10 slm) are characterized using optical emission spectroscopy (OES) and numerical simulation. A simultaneously two-wavelength OES method and Abel inversion of the measured images with a spatial resolution of 19.6 μm are applied. The collisional radiative model used in this study includes Coulomb collisions of electrons. An iterative method of plasma parameter determination is applied. The determined values of the electric field up to 49 Td and electron density up to 2.5∙1015 cm−3 fit well to the plasma parameters received with different diagnostics methods in comparable plasma sources. Additionally, the electric current, which is calculated using the determined reduced electric field and electron density, is compared with the measured one.

Quantitative determination of selected elements in infant baby formulae and baby food cereals commercially available in Serbia using the ICP OES method

The aim of this paper was the quantitative determination of some macro and trace elements, especially potentially toxic elements in the samples of infant baby formulae and baby food cereals commercially available in Serbia using the inductively coupled plasma optical emission spectrometry (ICP OES) method. Among the macro elements, K is the most abundant in all infant formulae samples, followed by Ca, P, Na and Mg. On the other hand, the analysis of food cereals showed that P is presents in the highest contents, followed by K, Ca, Na, and Mg. Potentially toxic elements As, Pb, Hg, and Cd were not detected in any sample of infant formulae, while Cd was detected and quantified in cereal foods. Also, the calculated values of Estimated Tolerable Weekly Intake (ETWI) as well as the Estimated Tolerable Monthly Intake (ETMI) were lower than recommended values for a tolerable weekly intake (TWI) and provisional tolerable monthly intake (PTMI).

On the Construction of a Calibration Curve Using a Glow Discharge Emission Spectrometer for Measuring the Hydrogen Content in Zirconium Alloys

One of the main directions of modern activity of metrology researchers is to provide the real sector of the economy of the Russian Federation with reference materials that have no analogues in the country. The article discusses the research of highly efficient materials for fuel cladding (fuel elements) in the active zones of thermal reactors, the scope of which is wide. The purpose of the study is the development of samples of the composition of the zirconium alloy to establish and control the stability of the calibration curves of spectrometers when determining the mass fraction of hydrogen, provided that the metrological and technical characteristics of the reference material meet the requirements of the measurement procedure. The main methods for determining the hydrogen content in materials are analyzed. It has been established that the method of glow discharge optical emission spectroscopy has found the widest application. It has also been established that zirconium alloys are chosen as the main material in most cases.The need to create samples for constructing a calibration curve for spectrometers for measuring the hydrogen content in a zirconium alloy is noted. Samples of zirconium alloy Zr-1Nb (grade Э110) have been developed to construct a calibration curve using a glow discharge emission spectrometer for measurements with a mass fraction of hydrogen from 0.034 to 0.498 %. Calibration is carried out using the developed samples to obtain a calibration curve using the example of an emission glow discharge spectrometer of the GD Profiler2 type. The relative error of the hydrogen mass fraction obtained during calibration does not exceed ± 10 %.The practical significance of the study lies in the development of samples that can be used to calibrate spectrometers based on the method of glow discharge optical emission spectroscopy.

Characteristics of the O(1S) to O(1D) 557.7 nm green emission observed in an argon plasma jet

An extensive study on the green auroral emission characterization is presented based on a single dielectric barrier discharge geometry argon plasma jet driven by a kHz sine voltage. The plasma was generated by using 99.999% pure argon and the observed 557.7 nm green line resulted from the excited O(1S) state. An optical emission spectroscopy method using line ratios of argon was used to obtain the electron density and electron temperature under different conditions in the downstream region. The characteristics of discharge and green emission with variations in interelectrode distance, applied voltage (power) and flow rate are discussed. The spatially diffuse distribution of O(1S), owing to its long lifetime, is shown by the short exposure imaging. Two discharge regimes are presented, accompanied by two distinct branches of the green emission intensity, with a clear conclusion that the 557.7 nm emission is favored in the low electron temperature environment. In this work, the intense and diffuse green plume only forms when the downstream electron density is approximately lower than 1 × 1014 cm−3 and the electron temperature is lower than 1.1 eV. By charging the two electrodes in two opposite ways, it is shown that the green emission from oxygen is favored in the case where the electric field and the electron drift are not continuous.

Ratiometric detection of lithium ions in serum and living cells using DNAzyme-assisted hybridization chain reaction

Lithium, a first-line mood stabilizer for bipolar disorder (BD), presents challenges due to its narrow therapeutic window (0.6–1.2 mM) and potential side effects in overdose. Hence, it is crucial to accurately and sensitively detect lithium ions (Li+) in serum and living cells for timely monitoring of BD progression and gaining mechanistic insight into lithium-based therapy. In this study, we design a Li+-responsive DNAzyme-HCR amplifier by combining hybridization chain reaction (HCR) and the Li+-specific DNAzyme. The presence of Li+ catalytically cleaves the DNAzyme, releasing the embedded HCR DNA trigger and generating numerous DNAzyme-assisted HCR products, ultimately activating the fluorescence resonance energy transfer response. Our results demonstrate that the DNAzyme-HCR amplifier enables amplified Li+ detection in serum, which are consistent with the results obtained using the inductively coupled plasma optical emission spectroscopy (ICP-OES) method. Furthermore, the DNAzyme-HCR amplifier allows for Li+ imaging in living cells, showing promising potential in monitoring treatment effects against BD.

DYNAMICS OF PLASMA IN A DUAL-FREQUENCY CAPACITIVE DISCHARGE IN AN AR/XE MIXTURE

The spatiotemporal dynamics of the plasma of a symmetrical dual-frequency 81 MHz/1.76 MHz capacitive discharge under the in uence of a low-frequency eld of 1.76 MHz has been studied.Using the method of phase-resolved optical emission spectroscopy, the dynamics of the radiation intensity of argon and xenon in plasma was obtained.The electron energy distribution function at the center of the discharge was measured using a Langmuir probe and the electron density was measured using a microwave probe. The main result is the dynamics of the intensity ratios of the selected argon and xenon lines depending on di erent conditions: at pressures of 40, 200 and 400 mTorr, LF voltage amplitude of 100, 200 and 400 V, input power at 81 MHz of 3 W and 15 W. The dynamics of high-energy electrons is studied based on a two-temperature approximation of the electron energy distribution function.

High Capacity Arsenate Removal from Real Samples Using Dihydrotetrazine Decorated Zirconium-Based Metal-Organic Frameworks.

Zirconium metal-organic frameworks (Zr-MOFs) are potential candidates for decontamination of water resources from harmful pollutants due to their modulable porosity and chemical stability in aqueous solutions. Linker functionalization is an approach for tuning the host-guest chemistry of Zr-MOFs and extends their applications in environmental monitoring. In this work, the structure of UiO-66(Zr) (formulated Zr6(OH)4O4(BDC)6, BDC2- = benzene-1,4-dicarboxylate) was functionalized with dihydrotetrazine group via postsynthesis linker exchange (PSLE) method. The functionalized framework, UiO-66(Zr)-DHTZ, was applied for the removal of arsenate ions from aqueous solutions. The results show that UiO-66(Zr)-DHTZ can adsorb 583 mg g-1 of As(V) at pH = 7 after 2 h, which is significantly higher than that of the UiO-66(Zr). According to X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR), the removal mechanism is based on possible hydrogen bindings between free -C-NH and -C═N- sites of dihydrotetrazine function with -O- and -OH sites of As(V) species. Removal tests in real samples show that UiO-66(Zr)-DHTZ still has a high capacity (220 mg g-1) to As(V) ions in complex matrixes and also can decrease the concentration of As(V) below the detection limit (0.05 ppm) of the inductively coupled plasma optical emission spectroscopy (ICP-OES) method. Since the dihydrotetrazine-decorated UiO-66(Zr)-DHTZ reaches one the highest adsorption capacities to As(V) species, it can be considered a potential candidate for water treatment in real-life applications.

A novel optical emission spectroscopy method for diagnostics of contribution of different ionization mechanisms and flux of ions in different valences in discharge channel of a Hall thruster

The mass application of Hall thrusters poses the need for a diagnostic method of ionization mechanism in the discharge channel to boost the iteration and optimization of thruster design. This work presents an Optical Emission Spectroscopy (OES) method for diagnostics of the contribution of different ionization mechanisms and the flux of ions in different valences in the discharge channel of a Hall thruster. The emission spectra in the discharge channel are analyzed by jointly utilizing a collisional-radiative model, an ionization-excitation model, and a flux-conservation model. It is found that the intensities of some spectral lines can be converted into the reaction rates of collision processes, e.g., electron-induced excitation and ionization processes. The latter can further be used to determine the evolutions of particle fluxes by utilizing the conservation law of matter. The novel method is demonstrated on a kilo-watt Hall thruster. The evolutions of several parameters are determined using this method along the discharge channel, including the ionization rates of different mechanisms, particle fluxes, particle densities, and particle velocities. This novel method can be further developed by being jointly utilized with spectral imaging and tomography techniques, enabling diagnostics of multi-dimensional distributions of the above-mentioned parameters in the discharge channel and near-field plume.

Concentration of Heavy Metals in Traditional and Industrial Fruit Juices from Iran: Probabilistic Risk Assessment Study.

Exposure to heavy metals can endanger the health of exposed people in the long term. The consumption of fruit juice is increasing; it is important to estimate the health risk of consumers due to heavy metals. The current study was carried out for the analysis of toxic metals (lead (Pb), arsenic (As), and cadmium (Cd)) and essential elements (copper (Cu) and zinc (Zn)) in 60 samples of traditional and industrial fruit juices (10 samples of different brands of apple, orange, grape, peach, mango, and pineapple) in Hamadan, West Iran, using inductivity coupled plasma optical emission spectrometry (ICP-OES) method. The validation protocol included precision of the analytical method; recovery, the determination of the limit of detection (LOD), the limit of quantification (LOQ), and linearity were measured. Moreover, risk assessment was detected using target hazard quotient (THQ) and cancer risk (CR) by the Monte Carlo simulation (MCS) model. The ranking of metal concentration in traditional and industrial fruit juices was Zn > Cu > As > Pb > Cd. In all samples, concentrations of heavy metals in industrial fruit juices were higher than traditional fruit juices p < < 0.001. The level of metals in all samples was lower of the US Environmental Protection Agency (USEPA), the World Health Organization (WHO), and the Iran Standard (IS) permissible limit set for drinking water. In terms of non-carcinogenic, values of toxic elements for children and adult in traditional and industrial fruit juices were 1.6E-3 and 1.72E-3 and 2.6E-3 and 1.85E-3, respectively. The 95th percentile of CR in adults and children due to both industrial and traditional fruits juices was higher than 1E-6; hence, reducing the concentration of As in fruit juices should be conducted. Consumption of fruit juice can increase carcinogenic risk of consumers. Therefore, it is recommended to consume it with caution.

DETERMINATION OF ECOTOXIC SUBSTANCES IN WASTEWATER FORMED IN THE PURIFICATION PROCESS OF PETROLEUM OILS WITH HYDROGEN BY SPECTRAL METHODS

The article analyzes the determination of the amount of dissolved ecotoxicants in the sample taken from the industrial wastewater obtained during the process of hydrogen treatment of petroleum oils. During the hydrogenation process, different types of wastes are formed, depending on the nature of each compound contained in petroleum distillates. Every gas, liquid, solid waste formed during the process of hydrogen purification of petroleum distillates by the oil refining industry has a negative impact on the environment in various ways. One of the main directions of our scientific research is the ecological assessment of the environmental impact of wastewater formed in the process of hydrogen treatment of petroleum distillates.Based on the results obtained, the environmental impact of the wastewater was assessed. The amount of volatile ecotoxicants in the wastewater sample was determined by spectral methods and is shown in the table. We used gas chromatography-mass spectrometry method for the polycyclic aromatic hydrocarbons; optical emission spectrometry method for metals; spectrometry method for phenols, dyes and fluorine; nephelometry method for turbidity; the gravimetry method for total suspended particles. Based on the results obtained, it is possible to assess the environmental impact of wastewater generated during the technological process at the hydrogen treatment plant. According to the results of the research, it can be noted that the industrial wastewater discharged from the oil refinery's facility № 501 has a content that will damage the ecosphere and biosphere, despite the fact that the discharge standards meet the permissible discharge limits

STUDYING THE CHEMICAL COMPOSITION OF WASTE WATER FOR THE PRODUCTION OF GLYCORRICE ROOT AND GLAUCONITE FROM KARAKALPAKIA

In the article, the amount of micro-and macro-elements in two types of glauconite produced during the industrial processing of licorice root from Beruni district of Karakalpakstan was studied based on the inductively coupled coil optical emission spectrometry method and compared with those in the literature. The obtained results were used to study the amount of macroelements K and R necessary for plants in the composition of soil and glauconite, and it was shown that it is possible to produce new types of organomineral fertilizers based on them. It has been shown that the processing of licorice root in our republic can solve the problems of disposal of industrial waste.Based on the obtained results, the scientific basis of organomineral fertilizer production was developed based on the studied glauconite and wastewater and licorice root industrial waste.

Promoting densification and grain growth of BaCe0.65Zr0.2Y0.15O3-δ

BaCe0.65Zr0.2Y0.15O3-δ (BCZ20Y15) has raised great interest due to its good protonic conductivity and chemical stability. However, the sintering of the material is considerably challenged by its refractory nature. In the current work, almost fully densified single-phase BCZ20Y15 with grain sizes exceeding 10 μm was successfully fabricated by sintering at 1500 °C by using calcined powders consisting of naturally separated perovskite phases and 0.5 wt% NiO. The role of NiO as sintering aid was elucidated by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Atom Probe Tomography (APT) methods, concerning global and local material composition. Furthermore, the mechanism leading to the promoted densification and grain growth is elucidated based on current experimental results and a comprehensive review of the literature.

Interaction of Cold Atmospheric Pressure Plasma with Soybean Seeds: Effect on Germination and DNA, Seed Surface Characteristics and Plasma Diagnostics

This study investigates the relation between cold atmospheric pressure plasma (CAPP) effect on seeds and the plasma parameters. As a source of CAPP, the diffuse coplanar surface barrier discharge (DCSBD) generated in nitrogen, ambient air, and oxygen at atmospheric pressure was used. Results of germination and the level of DNA damage of soybean seeds (Glycine max L.) treated in plasma and plasma gaseous products showed that the most advantageous is the use of ambient air plasma treatment. The water contact angle (WCA) of samples treated directly in plasma was significantly smaller than that of samples treated with gaseous products. Using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), we did not observe significant changes between the spectra of individual samples, what indicates that there is no damage on the surface of the samples during the treatment, only the binding of polar groups. The method of optical emission spectroscopy (OES) and Fourier transform infrared spectroscopy (FTIR) were used to study the plasma parameters. The most radiant system observed in ambient air and nitrogen plasma is the second positive system of nitrogen N2C3∏u→B3∏g\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{N}}_{2} \\left( {{\ ext{C}}^{3} \\prod _{{\ ext{u}}} \ o {\ ext{B}}^{3} \\prod _{{\ ext{g}}} } \\right)$$\\end{document}. FTIR measurements showed the presence of reactive oxygen and nitrogen species O3, NO2, N2O, NO, HNO2 depending on the working gas. Finally, it can be assumed that the positive effect of plasma on the seed is caused not only by the individual components of the plasma, but also by their synergistic effect, while the ratio of the individual active particles as well as the plasma exposure to the seeds are important.