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.

Neural network cognitive analysis of accumulation metals by marigold

The article presents the results of studies to assess the effect of humic acids, taken at a concentration of 250 ppm, on the process of induced phytoextraction of heavy metals from soils selected near Norilsk. Phytoxtraction was carried out by different types of marigold plants: Tagetes patula and Tagetes erecta. The studies were carried out in greenhouse conditions under controlled spectral illumination (light culture). The duration of the experiment was 21 days. A short vegetation period was chosen based on the conditions of a short summer period typical for this region, where it is more rational to keep records of the systemic removal of toxicants from contaminated soils by several cycles of their sowing/cutting per season, already at the juvenile phase of ontogenesis. For elemental analysis, the method of atomic emission spectrometry with inductively coupled plasma was used. To assess the level of efficiency of metal accumulation, the authors developed and used the original computing neural network CompNN, which allows calculating the cognitive significance index (CSI) based on empirical data on the accumulation of toxicants, both in shoots and roots of plants. The results of the study showed that the introduction of an organic additive in the form of humic acids into the soil led to inhibition of the growth of the above-ground part of T. patula. As for T. erecta, the rate of accumulation of green plant biomass did not change when humic acids were added. The decrease in the biomass of shoots of T. patula plants is explained by an increase in the accumulation of metals in them by an average of 91.6% for the variants. The content of metals in the shoots of T. erecta under the influence of humic acids, on the contrary, decreased by 17.3% on average. A similar result was observed in relation to the root zone: the trend of change in the fixation of metals for both plant species here was 40.8 and 10.8%, respectively. Calculation of CSI indices also showed that the addition of humic acids in T. patula increases the intensity of metal accumulation from the soil in its biomass in all variants, while in T. erecta, on the contrary, it decreases. The performed cluster analysis demonstrated the fixation of metals in the main buffer zone of plants, and also made it possible to isolate nickel into a separate homogeneous series. With regard to the distribution of this element in the shoots by variants, experience has shown that it has demonstrated here the proximity of convergence with copper. The correlation coefficients of their accumulation with the CSI index in the shoots of both plants were r = 0.82; 0.87 for Cu and r = 0.87; 0.83 for Ni. The proximity of these values indicates the priority nature of the accumulation of these metals in the plant biomass of marigolds, and also characterizes the manifestation of certain interactions between them in contaminated soil by the type of antagonism or synergism.

Potentially hazardous elements in atmospheric precipitation during the warm season (May–September) of 2019 in Moscow

Atmospheric precipitation acts as a significant pathway for pollutants from the atmosphere to the Earth’s surface, and analyzing urban precipitation data on intensity, fallout regime, transfer patterns, and solid particle content helps identify pollution sources. For the first time in the Moscow megacity, the levels of soluble forms of potentially hazardous elements (PHEs) in atmospheric precipitation were studied during the whole summer season of May–September 2019. The concentrations of Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cu, Fe, La, Li, Mn, Ni, P, Pb, Rb, Sb, Sn, Sr, and Zn were determined using inductively coupled plasma mass spectrometry and atomic emission spectroscopy methods. The research underscores the crucial role of atmospheric precipitation in washing PHEs out of the atmosphere. In May and September, concentrations of PHEs surpass the warm-season average. Notable contamination in May stems from elevated traffic during vacations, extensive burning of plant debris and wood, and pollen transport. Summer months are characterized by reduced forest and agricultural fires, traffic, and increased vegetation, leading to lower PHE concentrations, especially in July, with typical amount of precipitation contributing to pollutant dispersion. Elevated PHE levels in September are observed due to increased traffic load, biomass burning, and the expansion of unvegetated soil areas. Rainwater is enriched with Sb, Pb, Cd, Zn, Cu, B, Bi, P, and Sr, sourced from vehicle emissions, soil particles, industry, construction dust, biomass burning, and forest fires. Moderate enrichment with Ba, Mn, Ni, Co, and Sn also occurs episodically. Regression analysis highlights solid particles’ role as a major PHE source in rainwater, with the longer antecedent dry periods and the higher acidity level of rain intensifying the accumulation of PHEs. Long-range transport plays a lesser role, with Southern and Northern Europe, Western Siberia, and the central part of European Russia contributing meaningfully.

Study of a Helicon Plasma by Emission Spectroscopy Methods

Study of a Helicon Plasma by Emission Spectroscopy 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.

Analysis of sulfur in soil and plant digests using methane as a reaction gas for ICP-MS

Quantitation of sulfur (S) is vitally important for analysis of agricultural soil and plant samples due to the requirement of S in living organisms. Although inductively coupled plasma mass spectrometry (ICP-MS) is a commonly used and robust instrument for multi-elemental detection, S is usually analysed by ICP-optical emission spectroscopy (OES) since S quantitation poses a particular challenge for ICP-MS due to interferences on all S isotopes. The requirement for analysis by two instruments increases time and cost for sample analysis, hence analysis by one instrument is desirable. The use of reaction gases in ICP-MS can improve the performance by shifting S to a mass for detection where no interference is present. This work explored the potential of methane as a reaction gas for analysis of S in soil and plant samples to give users an alternative option to oxygen. The product ion clusters CH2SH+ were monitored (m/z 47 and 49 on ICP-MS and with mass shift of +15 from Q1 → Q2 using 32 → 47 and 34 → 49 on triple quadrupole ICP-MS). As expected, triple quadrupole ICP-MS performed better than single quadrupole ICP-MS containing a reaction cell due to the ability to preselect the m/z of choice and remove ions that may react with methane in the reaction cell. The method detection limit (MDL) was 150 mg kg−1 S for plants and 53 mg kg−1 S for soils which is fit for requirements. This is the first-time methane has been reported as a reaction gas for analysis of S and shows promising results for agricultural samples when using a triple quadrupole ICP-MS. Results compared well to those obtained via the more commonly used ICP-optical emission spectroscopy (OES) method with results <20 % for all samples. Interlaboratory comparison samples were within 2 Z-scores of the consensus mean. In the absence of ICP-MS/MS, Q-ICP-MS with detection of cluster m/z 47 was deemed to be suitable for detection of S in plant samples, with acceptable MDL (250 mg kg−1 S), acceptable precision (<20 % RSD) and <20 % variation to the reported ICP-OES result.

Elemental tracer determination and modeling for geographical origin designation of sweet oranges

Sweet oranges have long been an integral part of global health and culinary practices, offering a wealth of nutrients and bioactive compounds. Ensuring the authenticity of these citrus fruits is essential for maintaining consumer confidence, promoting transparency in sourcing, and protecting producers' reputations in the marketplace. In this study, we explored the feasibility of using multi-element profiling combined with pattern recognition algorithms to trace the origin of sweet orange samples. To achieve this, we employed an optimized microwave plasma atomic emission spectroscopy (MP-AES) method to analyze the elemental composition (Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, and Zn) of 183 orange samples from four production regions in northeastern Argentina. Support vector machine (SVM), random forest (RF), and gradient boosting tree (GBT) models were then built using the collected data to identify elemental tracer's indicative of origin. Based on a comprehensive evaluation of overall accuracy, receiver operating characteristic (ROC) curves, and area under the curve (AUC), the GBT model demonstrated the best classification performance, achieving a 96.5 % correct prediction rate on test samples, as confirmed by the ROC curve (AUC = 0.973). Consequently, this approach provides compelling evidence for the potential utility of MP-AES combined with supervised modeling to determine the geographic origin of sweet oranges produced in Argentina, thereby contributing to consumer protection against fraud.

Effect of Microwave Antenna Material and Diameter on the Ignition and Combustion Characteristics of ADN-Based Liquid Propellant Droplets

Microwave-assisted ignition is an emerging high-performance ignition method with promising future applications in aerospace. In this work, based on a rectangular waveguide resonant cavity test bed, the effects of two parameters (material and diameter) of the microwave antenna on the ignition and combustion characteristics of ADN-based liquid propellant droplets were investigated using experimental methods. A high-speed camera was used to record the droplet combustion process in the combustion chamber, the effect of the microwave antenna on the propellant combustion response was analyzed based on the emission spectroscopy method, and finally, the loss of the microwave antenna was evaluated using a scanning electron microscope. The experimental results show that the droplet has the lowest critical ignition power (179 W) when the material of the microwave antenna is tungsten, but the ignition delay time is higher than that of copper. A finer diameter of microwave antenna is more favorable for plasma generation. At a microwave power of 260 W, the ignition delay time of the droplet with a microwave antenna diameter of 0.3 mm is 100 ms lower than that of 0.8 mm, which is about 37.5%. In addition, this study points out the mechanism of microwave discharge in the droplet combustion process. The metallic microwave antenna not only collects the electrons escaping from the gas discharge, but also generates a large amount of metallic vapor, which provides charged particles to the plasma. This study provides the possibility for the application of microwave-assisted liquid fuel ignition.

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) (&amp;gt; 95 % recovery with &amp;lt; 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).

Rapid determination of germanium in lignite coal and coal-related solid byproducts by graphite furnace digestion inductively coupled plasma emission spectroscopy

This study developed a rapid and efficient graphite furnace digestion combined with inductively coupled plasma emission spectrometry (ICP-OES) method, enabling precise quantification of germanium (Ge) in coal and various coal-derived metallurgical byproducts across a broad concentration level (∼ppm-n%). The graphite furnace digestion conditions were examined intensively as a function of the acid amounts of HNO3 and HF (5–10 mL), temperature (80–180 °C), time (1–5 h), and acid drive methods (H3BO3 neutralization versus heating). Coal references including SARM 19, SARM 20, NIST SRM 1632e, and fly ash standard NIST SRM 2689 were tested. The optimum recovery of germanium was obtained when the HNO3 dosage, HF dosage, solid sample mass, temperature, and duration time were 10 mL, 5 mL, 0.1 g, 80 °C and 1 h. Agreement of 95.15–96.54 % between the measured and certified value was obtained under the optimum conditions. The spiked recovery was 103.23–103.54 %, indicating the matrix-analytes interactions were negligible. Boric acid neutralization reduced the recovery rates to 47.2–49.3 % and was not be appropriate for driving HF. The optimal spectral line for determining Ge is at a wavelength of 265.117 nm, at which the limit of detect and the limit of quantification were 0.46 μg L−1 and 1.53 μg L−1, respectively. The applicability of the method was validated by quantifying Ge in Ge-rich lignite, fly ashes (FA), and chlorinated distillation residue (CR) samples. The concentration of Ge in coals was 44.75–225.41 μg g−1, the content in FA was 0.68%–2.3 %, and the content in CR was 0.18 %, with the uncertainty of the method obtained being less than 0.5 %. X-ray fluorescence spectrometer (XRF) was used to verify the results. The difference between XRF data and ICP-OES data was less than 5 %, confirming the accuracy and reproductivity of the analytical method.

An electrochemical biosensor for the detection of sodium ions in serum based on Ce13d DNAzyme

In this study, a Ce13d DNAzyme-based electrochemical biosensor for the detection of sodium ions (Na+) in the serum was developed. The indium tin oxide (ITO) electrode was modified with Au gold nanoparticles (AuNPs), then immobilized with double-stranded DNA formed by thiol of substrate strand and enzyme strand bound via Au-S link. In the presence of Na+, the resulted Ce13d DNAzyme could preferentially bind Na+, and induced local folding of Ce13d to form a G-quadruplex-like structure, which enhanced binding ability to methylene blue (MB). By using the specificity of DNAzyme and change of its conformation, the quantitative detection of Na+ could be achieved. Thus, the developed sensing platform could identify Na+ with a linear response range of 10 nM-100 mM and a detection limit of 1.03 nM. The electrochemical biosensor also exhibited excellent selectivity for Na+ in the presence of five interfering ions, including K+, Cu2+, Mg2+, Zn2+ and Ca2+. Furthermore, the proposed biosensor showed satisfactory results for Na+ in serum sample analysis, which highly correlated with the inductively coupled plasma atomic emission spectrometry method. This work demonstrated a simple and reliable method for Na+ in serum, which opens the way for potential applications in disease diagnosis and environmental testing.

Mineral Composition of Blackcurrant (Ribes Nigrum L.) Fruits and Leaves

Background Plants as living systems are characterized by the appropriate degree of accumulation of macro- and microelements, which, acting as factors of the external environment, are basic modulators for synthesizing biologically active substances. Blackcurrant (Ribes nigrum L., Grossulariaceae) is widespread worldwide. Berries, leaves, and buds are medicinal raw materials in folk medicine. The regularity of inorganic elements accumulation in this plant and their impact on the quality of raw materials are topical and need to be studied. Aims This work aimed to study the mineral composition of R. nigrum raw materials collected in Western Ukraine (Ivano-Frankivsk and Ternopil regions) and find the regularity of their accumulation in the plant parts and from the soils. Methods The elemental compositions of R. nigrum fruits and leaves, as well as the soils of the growth places, were studied using the method of atomic emission spectrometry with inductively coupled plasma iCAP 7000 Duo. Results The content of 19 inorganic elements in R. nigrum raw materials was established. Their quantities don’t differ significantly depending on the growth places. All the fruits had high K, Na, Mg, P, and Ca contents, which were slightly lower in leaves. Thus, the fruits contain 590-675 mg/kg of Mg, while in leaves, there are just 98-106 mg/kg. Most of Fe was accumulated in the fruits (73-85 mg/kg). The content of Mn was observed in the leaves (57-64 mg/kg), slightly higher than in the fruits (47-51 mg/kg). The content of heavy metals in the objects was within the permitted limits of European Pharmacopeia. The results testify to the inverse relationship between the content of most elements in the soils and the coefficient of their accumulation in the plant. Conclusion The content of macro- and microelements in R. nigrum fruits and leaves had similar profiles but differed in their quantitates. The regularity of element accumulation in R. nigrum raw materials corresponds to the following profile in accordance with their quantitative content in the raw materials: K&gt; Na&gt; P&gt; Mg&gt; Ca&gt; Si&gt; Fe&gt; Mn&gt; Al&gt; Se&gt; Zn&gt; Cu&gt; Co&gt; I&gt; Pb&gt; Ni&gt; Mo&gt; Sr&gt; Cd. The regularity of their accumulation in the plant parts from the soils was established.

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.

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).

Preparation and application of silver nanoparticle capped carbon dots composite as fluorescent probe for cobalt determination in vitamin B12 supplement samples

A simple and economical material of fluorescence nanocomposite was developed to quantify vitamin B12 through cobalt(II) ion measurement. The material was derived from carbon dots capped with silver nanoparticles, forming spherical AgNPs@CDs composite with the average diameter of 8.7 nm, expressing unique optical properties, and was used as an optical probe for Co(II) ion determination. The synthesized AgNPs@CDs showed a maximum absorption peak at the wavelength of 406 nm, while their fluorescence peak appeared at the wavelength of 526 nm under the excitation wavelength of 406 nm. The nanocomposites exhibited stable fluorescence with IC50 value against human cholangiocyte cell line of 137.7 ppm after 24 h of the treatment. The interaction between Co(II) ions and AgNPs@CDs effervesced molecular oxygen and caused fluorescence quenching of the composite material. The optimum conditions for Co(II) ion detection were pH 10, volume ratio between AgNPs@CDs and Co(II) ion of 0.10:0.90, and reaction time of 30 min. The linearity range based on the Stern–Volmer plot was 0.05–10.00 ppm, and the limit of detection and limit of quantification were 0.032 ppm and 0.095 ppm, respectively. The developed approach was used to determine the extracted Co(II) ions in commercial vitamin B12 supplement samples and their spiked extracts. The results showed good agreement with those from a conventional method of atomic emission spectrometry, and acceptable range of recovery from 90.0 to 105.0 % was obtained. The fluorescence quenching mechanism of the AgNPs@CDs was elucidated based on the characterization information from several analytical techniques, and electrocatalytic reaction between the nanocomposite and Co(II) species was proposed.

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.