Lines Of Cu Research Articles

Effect of Femtosecond Ultraviolet and Infrared Laser Wavelength on Plasma Characteristics of Metals, Ceramics and Glass Samples Using Femtosecond Laser-Induced Breakdown Spectroscopy.

In this work, we present studies on the effect of laser wavelengths on the laser-induced plasma characterization using a femtosecond (fs) ytterbium-doped potassium-gadolinium tungstate (Yb:KGW) laser. Plasma plumes of copper, steel, ceramics, and glass samples were induced using a multiple shot of 200 fs laser pulses with 1030 nm and 343 nm wavelengths at fixed laser fluence () and analyzed using the laser-induced breakdown spectroscopy (LIBS) technique. Time-resolved fs-LIBS measurements were performed on the same set of samples and under the same experimental conditions. For the calculation of plasma parameters, the set of spectral lines of Cu(I) (for copper sample), Fe(I) (for steel sample), and Ca(I), K(I) (for glass and ceramics samples) were observed. The plasma electron temperature and density were evaluated from the Boltzmann plots and Stark-broadening profiles of the plasma spectral lines, assuming the local thermodynamic equilibrium condition. Time-resolved plasma temperature and electron density for fs-LIBS using ultraviolet (UV) and infrared (IR) laser wavelengths were analyzed and no significant dependence on fs laser wavelength was observed for any of the samples. However, for all samples the signal-to-noise ratio (SNR) significantly increased using UV laser radiation: copper (), steel (), glass (), and ceramics (). Therefore, by using a fs UV laser wavelength for laser-induced breakdown spectroscopy experiments, for certain materials the SNR and at the same time the limit of detection can be significantly enhanced.

INVESTIGATION OF SPATIAL DISTRIBUTION OF METAL VAPOURS ADMIXTURES IN THE PLASMA OF AN ELECTRIC ARC DISCHARGE

This work focuses on diagnosing the plasma in an electric arc discharge in an argon flow using optical emission spectroscopy. The method employed for determining the population of energy levels and the concentration of metal atoms based on the absolute values of emission intensity is described and validated. The experimental setup includes a spectrograph and an RGB CMOS matrix as the emission registration device. By obtaining the absolute values of the spectral radiances of Cu I lines and considering the axial symmetry of the electric arc discharge, the local radiation intensity of these lines is determined. Radial distributions of copper atom concentrations are then calculated using the absolute values of emission intensities and the radial distribution of the excitation temperature, which is determined using the Boltzmann plots technique. Two methods are employed for calculating the atom concentrations. The first method involves Boltzmann plots based on four spectral lines of Cu I and the corresponding excitation temperature. The second method determines the concentrations directly from the population of copper's energy levels, which are derived from the absolute values of emission intensity of the Cu I spectral lines. The results obtained from these two methods exhibit a coincidence of within 20%, supporting the recommendation of this technique for plasma diagnostics in electric arc discharges.

Laser-assisted plasma formation and ablation of Cu in a controlled environment

In this paper, we explore the surface and mechanical alterations of Cu, as well as the parameters of laser-assisted plasma and ablation. The irradiation source is a Nd: YAG laser with a constant irradiance of 1.0 GW/cm2 (1064 nm, 55 mJ, 10 ns, 10 Hz). Physical parameters such as electron temperature (Te) and electron number density (ne), sputtering yield (yield), ablation depth (depth), surface morphology (morphology), and hardness (Vickers) of laser irradiated Cu are evaluated using instruments such as a Laser Induced Breakdown Spectrometer (LIBS), Quartz Crystal Microbalance (QCM), Optical Emission Microscope (OEM), Scanning Electron Microscope (SEM), and Vicker's hardness tester. These physical characteristics have been studied in relation to changes in pressure (from 10 torr to 100 torr) and the composition of two inert ambient gases (Argon and Neon). Pressures of Ar and Ne are found to enhance the emission intensities of spectral lines of Cu, Te, and ne, as well as the sputtering yield, crater depth, and hardness of laser ablated Cu, to a maximum at 60 torr, after which they decrease with subsequent increases in pressure up to 100 torr. Increases in pressure up to 60 torr are connected with plasma confinement effects and increased collisional frequency, whereas decreases in pressure between 60 and 100 torr are ascribed to shielding effects by the plasma plume. All numbers are also found to be greater in Ar compared to Ne. In Ar, laser-ablated Cu reaches a maximum of 15218 K, 1.83 × 1018 cm−3, 8.59 × 1015 atoms/pulse, 231 m, and 147 HV, whereas in Ne, it reaches a maximum of 12000 K, 1.75 × 1018 cm−3, 7.70 × 1015 atoms/pulse, 200 m, and 116 HV. Ar is more likely than Ne to develop surface features such as craters, distinct melting pools with elevating edges, flakes, cones, etc. It is also shown that there is a significant association between the outcomes, with an increase in Te and ne being responsible for a rise in sputtering yield, ablation depth, surface morphology, and surface hardness. These findings have potential uses in plasma spectroscopy for materials science and in industrial applications of Cu.

In situ determination of sputtered Ni–Cu film composition from emission intensities

In situ elemental analysis of films comprising multielements deposited by sputtering is necessary to improve the reliability of the films because small changes in the film composition affect the properties of the films. Recently, we developed a method to determine the composition of Cu–Zn films by measuring the intensities of emission lines of Cu and Zn during sputter deposition. However, this method was only applicable to a constant chamber pressure, and only a narrow composition range (65.9–80.6 at. % of Cu in the target) was investigated. In this study, the applicability of this method was investigated for a wide range of film compositions, and the combination of emission lines that can be used to determine the film composition regardless of the chamber pressure was determined. This was achieved using Ni–Cu alloy targets, whose Cu composition ranged from 29.4 to 85.3 at. %, by evaluating the linearity (R2 value) between the emission intensity ratio of Ni/Cu lines and the atomic ratio of Ni/Cu in the films. An R2 value of 0.9870 was obtained for the combination of Ni 338.1 nm and Cu I 296.1 nm lines at chamber pressures from 1 to 5 Pa. This result indicates that the composition of Ni–Cu films can be determined from the intensities of the emission lines of Ni and Cu during sputter deposition regardless of the chamber pressure.

Investigation of emission lines for in-situ elemental analysis of Cu–Zn films deposited by sputtering

Sputter deposition is the most widely used technique to obtain thin films for industrial products. However, the conventional method for achieving the desired composition for films comprising multiple elements is time-consuming because the deposition conditions to obtain the desired film composition are determined by repeating post-deposition elemental analysis of the films under different deposition conditions. In this paper, we focus on optical emission spectroscopy during sputter deposition for in situ elemental analysis of films and report a method for selecting emission lines to determine the film composition. We investigated the linearity between the emission intensity ratio of Cu I lines to Zn I lines for Cu–Zn targets and the atomic ratio of Cu/Zn in the deposited films. The results indicated that the conventional method of selecting emission lines with the highest intensity did not produce the highest R2 value because the intensity of the Cu I 296.1 nm line, which produced the highest R2 value (0.986) with the Zn I 307.6 nm line, was 1% of the intensity of the Cu I 324.8 nm line, which had the highest intensity. The linearity remained almost unchanged at any fixed chamber pressures; however, it decreased at different chamber pressures. Therefore, the composition of Cu–Zn films deposited by sputtering can be determined in situ from the emission intensity ratios at a fixed chamber pressure using the intensity ratio of Cu I lines to Zn I lines with high R2 values.

Calibration capacity of hot-pressed hydrogen standards for glow discharge optical emission and mass spectrometry

Mixed copper and titanium hydride powder was hot-pressed and characterized by Carrier Gas Hot Extraction, X-Ray Diffraction, Thermal Gravimetric Analysis coupled with Mass Spectrometry, and Scanning Electron Microscopy. The hot-pressed and five conventional samples were applied for calibration of hydrogen in Glow Discharge Optical Emission and Mass Spectrometry. Up to the introduction of 15 ng/s hydrogen the emission yield model is useful in Glow Discharge Optical Emission Spectrometry. A correlation between saturation and even reversal of the emission yield of the spectral lines H121, H486 and H656 and low sputtering rates was found. Hydrogen effects exist for the spectral lines of Cu(II) 219 and Ti(I) 399. In Glow Discharge Mass Spectrometry, a linear dependency of the 1H ion current on the sputtered mass per time exists over the total range of hydrogen content investigated. Hydrogen effects also exist for the sensitivity of 48Ti and 63Cu. The sputtering rate of two-phase materials depends linearly on the sputtered mass per time of one phase, which allows the sputtering rate of two-phase materials with known composition to be predicted.

Influence of Plasma Parameters on Light Emission in GD-OES Analysis of Ni–Cu System

Abstract In the present work, an effect of plasma-forming parameters on light emission during analysis by glow discharge optical emission spectrometry of Ni–Cu model alloys is studied. To evaluate the effects of plasma-forming parameters on light emission, argon pressure was varied in the range between 600 Pa and 1000 Pa under a constant power of 20 W. Moreover, a variation of power at 20 W and 30 W under a constant Ar pressure of 1000 Pa was investigated. An effect of the element content on light emission was found. Namely, for Cu, a monotonic, non-linear increase in measured light intensity with an increasing Cu content was found. Surprisingly, for pure Ni, a lower light intensity was measured as for Ni90–Cu10 (at.%). Possible reasons causing this was listed as: (i) possible effect of hydrogen, (ii) overlapping of lines for Cu and Ni and (iii) self-absorbing of Ni line at 341.574 nm.

Plasma electrolytic oxidation of brass

Plasma electrolytic oxidation (PEO) is first reported for the non-valve metal of brass. The surface morphology of the PEO-treated brass has been examined, indicating the formation of a porous layer similar to that of PEO of valve metals. Abundant lines of Cu and Zn in the optical emission spectra (OES) of the PEO plasma confirm the participation of substrate in the oxide formation. Plasma electron temperature has been estimated by two-line method based on species of Cu, Zn and H, respectively, and also the Boltzmann plot with multiple lines of Cu I. The temperature lies between ~4393 and ~6911 K. However, the spectral lines of Cu I in ultraviolet region are found to be not suitable for temperature estimation. The coating contains crystalline phases of CuO, Cu2O and ZnO, as well as amorphous SiO2. Tribological tests show that the wear resistance of the PEO-treated brass is nearly ~16 times that of the uncoated metal. The mechanism of the PEO of brass has also been discussed.

Student Deployed Compu-Graphical Methods for Electrochemistry Education

Spreadsheets enhance student acquisition of electrochemical concepts at both undergraduate and graduate levels. The interactive nature of compu-graphical methods allows students more rapid and therefore extensive exploration of electrochemical concepts in thermodynamics, kinetics, and electrochemical methods. Here, several instructional tools are described with focus on the potential axis. Potential Axis - A Spreadsheet for Thermodynamics, Voltammetry, and Electrolysis For reactions A + ne ⇌ B at standard potential EA⁰ and C + me⇌D at EC⁰, calculation of standard cell potential Ecell⁰ = EA⁰ -EC⁰ for net reaction mA + nD ⇌ mB + nC yields thermodynamic information of standard free energy for the reaction ΔGcell⁰ = -nmFEcell⁰. In turn, ΔGcell⁰ identifies spontaneity when ΔGcell⁰ < 0 and equilibrium when ΔGcell⁰ = 0. When more than two reactions are possible or when pH changes for proton dependent reactions or oxygen is present or not, developing chemical intuition about the system and identifying stable species and thermodynamic reaction energies is more complicated. By plotting the reactions on a potential axis, thermodynamic assessment is readily obtained. Under IUPAC conventions with positive potential E to the right, reaction A + ne ⇌ B is plotted as B|A at potential EA⁰ on the potential axis. On addition of a second reaction C + me ⇌ D where EA⁰ < EC⁰, a simplified potential axis is B|A........D|C where potential is positive to the right. When chemical species are on the outside of the E⁰ lines, reaction is spontaneous. For example, if the axis for the A B couple and the C D couple is B|A........D|C , B and C react to form A and D spontaneously. Any other combinations of species are thermodynamically stable (B+A+D and C+D+A). A potential axis is shown below for several copper species at pH = 0. Because Cu and O₂ are outside the E⁰ vertical axes at 0.34 and 1.23 V vs NHE, Cu reacts spontaneously with O₂ based on thermodynamic potentials ECu²⁺|Cu⁰ and EO₂|H₂O⁰. Several other observations about copper electrochemistry are of note. Copper metal Cu is stable in strong acid. Cu⁺ is not observed in water because Cu⁺ is outside the vertical E⁰ lines for Cu⁺|Cu²⁺ and Cu|Cu⁺, so Cu⁺ reacts spontaneously with itself (disproportionation) to form copper metal and cupric cation. Cu is stable in HCl but not oxidizing HNO₃. Nickel metal and Zn metal (Zn|Zn²⁺ not shown at -0.76 V vs NHE) react spontaneously with both HCl and HNO₃. Potential axes are also useful for mapping voltammetry and identifying the sequence of electrolysis steps. Consider a system that contains Cu, Cu²⁺ and Cl⁻ in an aqueous system that is not degassed (contains O₂) at pH = 0. Based on the reactions plotted on the potential axis for copper, the species that are present and can be oxidized will be oxidized in sequence as potential E is swept from negative to positive. Species are oxidized in the sequence Cu then H₂O; because water is the solvent, chloride will not be accessible for oxidation to chlorine. Species that are present and can be reduced, are reduced in ranked in order for E swept from positive to negative as O₂, Cu²⁺, and H⁺. If pH changes, the formal potentials E⁰' for O₂, H⁺, and NO₃⁻ will also shift and the order of reactions can change. Note that as shown, neither concentrations other than standard conditions nor metal ions precipitated as oxides and hydroxides are not included but can be introduced. Several other ideas will be discussed briefly. Compu-graphical finite difference simulations for cyclic voltammetry for use at the undergraduate and graduate levels. (Thanks to Alanah Fitch who first suggested the form for undergraduates.)Useful ideas to convey include: • the concept of flux as number per area per time • electrochemical systems are circuits composed of electron and ion conductors • relationship between measurement rates and kinetic rates • difference between equilibrium (thermodynamics) and steady state (kinetics) • diffusion length ℓ² ≈ Dt (diffusion coefficient and time) and use in characterizing micro- and nano-structures on electrodes ...... Figure 1

Identification of a haptoglobin-hemoglobin complex in human blood plasma

Blood plasma metalloproteins that contain copper (Cu), iron (Fe), zinc (Zn) and/or other metals/metalloids are potential disease biomarkers because the bloodstream is in permanent contact with organs. Their quantification and/or the presence of additional metal-entities or the absence of certain metalloproteins in blood plasma (e.g. in Wilson's disease) may provide insight into the dyshomeostasis of the corresponding metal (s) to gain insight into disease processes. The first step in investigating if the determination of plasma metalloproteins is useful for the diagnosis of diseases is their definitive qualitative identification. To this end, we have added individual highly pure Cu, Fe or Zn-containing metalloproteins to plasma (healthy volunteer) and analyzed this mixture by size-exclusion chromatography (SEC) coupled to an inductively coupled plasma atomic spectrometer (ICP-AES), simultaneously monitoring the emission lines of Cu, Fe and Zn. The results clearly identified ceruloplasmin (Cp), holo-transferrin (hTf), and α2-macroglobulin (α2M), which verifies our previous assignments. Interestingly, another major Fe-peak in plasma was identified as a haptoglobin (Hp)-hemoglobin (Hb) complex. This Hp-Hb complex is formed after Hb, which is released during the hemolysis of erythrocytes, binds to the plasma protein Hp. The Hp-Hb complex formation is known to be one of the strongest interactions in biochemistry (Kd≈1pmol/L) and is critical because it prevents kidney toxicity of free Hb. Hence, the simultaneous determination of Cp, hTf, α2M and the Hp-Hb complex in plasma in <25min has the potential to provide new insight into disease processes associated with the bioinorganic chemistry of Cu, Fe and Zn.

Compact instrumentation and (analytical) performance evaluation for laser-induced breakdown spectroscopy

In this work, a compact laser induced breakdown spectroscopy (LIBS) instrument was developed based on a high energy lightweight laser source and an integrated control system, making the instrument well integrated and convenient to use. The instrument has a compact size of 45 cm ×36 cm ×45 cm and weights only 21 kg. The spectrometer operated in the range from 180 to 850 nm with a resolution of 0.15 nm, which was customizable. The client software was customized as the interface for process control and data acquisition. Some procedures were carried out to evaluate the performance of this instrument. First, the laser source worked at an average energy value of 116 mJ, with a relative standard deviation of 2.58% for 9999 laser pulses after continuously running for 3 hr. Second, qualitative analysis was performed to show the classification ability for copper mineral samples. Besides, the calibration curves were achieved by using the emission lines of Cu (I) 510.55 nm, Cu (I) 521.82 nm, Zn (I) 307.58 nm, and Zn (I) 328.23 nm, with the correlation coefficient R2 of 0.97432, 0.9826, 0.97286, and 0.98176, and the limit of detection was shown to be 0.0365%, 0.0399%, 39.581 µg·g−1, and 47.081 µg·g−1, respectively. According to the evaluation results, the compact laser source was excellent for stable measurement and the proposed compact instrument performed well for the qualitative and quantitative elemental analysis with satisfied results. Therefore, the proposed LIBS instrument has potential to find applications in a variety of circumstances.

Confirmation of Incorporation of Cu and Se Ions in Applied p- and n-Type-Doped Sb2S3 by Photoemission Spectroscopy

The effect of incorporating copper (Cu) and selenium (Se) ions into stibnite (Sb2S3) lattice was investigated using x-ray photoelectron spectroscopy (XPS). The incorporation of Cu and Se ions was verified by comparing the XPS spectra of the undoped (amorphous Sb2S3), doped (p and n-doped) and pure Se and Cu-acetate powders. The main photoelectron Cu 2p1/2 (951.8 eV) and Cu 2p3/2 (932.1 eV) lines derived from the Cu-doped and Cu-acetate powder samples were clearly observed, whereas in the undoped sample, none of the characteristic lines of Cu were detected. The Se Auger line (138.6 eV), the only line of Se which does not coincide with the lines of Sb and S, was successfully detected in an Se-doped XPS sample and the spectrum of pure Se, while Se in the undoped sample was not found. Further, the XPS measurements revealed the relative amounts of Cu and Se in antimony sulfide, as well as the oxidation state of copper incorporated into the matrix.

Chemical Sensitivity of Valence-to-Core X-ray Emission Spectroscopy Due to the Ligand and the Oxidation State: A Computational Study on Cu-SSZ-13 with Multiple H2O and NH3 Adsorption

Valence-to-core X-ray emission spectroscopy (vtc-XES) is a powerful experimental tool that can overcome the sensitivity limitations of X-ray absorption near edge structure (XANES) measurements with regard to ligand identification. To further elucidate the sensitivity of this experimental technique, the corresponding emission spectrum of a Cu cation when exchanged within a chabazite structure (Cu-SSZ-13) was calculated from first principles. By comparing vtc-XES spectra of H2O and NH3 adsorbed on Cu+ (or Cu2+) cations, we find a blue shift for the kβ″ lines from a Cu–O to a Cu–N ligation. In addition, the adsorption of NH3 results in a stronger kβ2,5 line intensity than the corresponding one for H2O. Therefore, one can discriminate the adsorption of H2O or NH3 by the different vtc-XES emission lines of Cu–O and Cu–N. By scanning the vtc-XES of multiple H2O and NH3 adsorbed Cu-SSZ-13 structures, we find a shift in the energy of the kβ″ line between H2O and NH3 adsorbed conformations, which increases by incr...

Optical and Electrical Investigation of Transition From Anode Spot Type 1 to Anode Spot Type 2

This paper presents differences between anode spot type 1 and type 2 and the discharge conditions for a transition from anode spot type 1 to type 2 are investigated by means of optical and electrical measurements. The transition from the diffuse mode to the high-current anode modes (footpoint, anode spot type 1, and anode spot type 2) is studied with respect to spatial and temporal distributions of different ionization levels of Cu lines, voltage–current waveforms, transferred charge, and aspect ratio. The driving current pulse was applied by a high-current generator which corresponds to a pulsed dc of 10-ms duration. Spectral lines of Cu I, Cu II, and Cu III are analyzed for various anode modes using a combination of an imaging spectrograph and a high-speed camera. The results show that during the formation of the anode spot type 2, the intensity of all lines change noticeably. Significant differences are found, for example, in the spatial structure of Cu III lines in the anode spot modes. A jump in the arc voltage corresponding to the time of intensity changes appears at the transition from anode spot type 1 to type 2. The impact of transferred charge, instantaneous current, and aspect ratio on the formation of the anode spot type 2 is also investigated. The transition from anode spot type 1 to type 2 is dominated by the ratio of electrode diameter to gap length. The formation of an anode plume is always observed after extinction of anode spot type 2 and before current zero.

Mapping of the spatial distribution of silver nanoparticles in root tissues of Vicia faba by laser-induced breakdown spectroscopy (LIBS)

The manuscript presents a procedure for optimal sample preparation and the mapping of the spatial distribution of metal ions and nanoparticles in plant roots using laser-induced breakdown spectroscopy (LIBS) in a double-pulse configuration (DP LIBS) in orthogonal reheating mode. Two Nd:YAG lasers were used; the first one was an ablation laser (UP-266 MACRO, New Wave, USA) with a wavelength of 266nm, and the second one (Brilliant, Quantel, France), with a fundamental wavelength of 1064nm, was used to reheat the microplasma. Seedlings of Vicia faba were cultivated for 7 days in CuSO4 or AgNO3 solutions with a concentration of 10µmoll−1 or in a solution of silver nanoparticles (AgNPs) with a concentration of 10µmoll−1 of total Ag, and in distilled water as a control. The total contents of the examined metals in the roots after sample mineralization as well as changes in the concentrations of the metals in the cultivation solutions were monitored by ICP-OES. Root samples embedded in the TissueTek medium and cut into 40µm thick cross sections using the Cryo-Cut Microtome proved to be best suited for an accurate LIBS analysis with a 50µm spatial resolution. 2D raster maps of elemental distribution were created for the emission lines of Cu(I) at 324.754nm and Ag(I) at 328.068nm. The limits of detection of DP LIBS for the root cross sections were estimated to be 4pg for Cu, 18pg for Ag, and 3pg for AgNPs. The results of Ag spatial distribution mapping indicated that unlike Ag+ ions, AgNPs do not penetrate into the inner tissues of Vicia faba roots but stay in their outermost layers. The content of Ag in roots cultivated in the AgNP solution was one order of magnitude lower compared to roots cultivated in the metal ion solutions. The significantly smaller concentration of Ag in root tissues cultivated in the AgNP solution also supports the conclusion that the absorption and uptake of AgNPs by roots of Vicia faba is very slow. LIBS mapping of root sections represents a fast analytical method with sufficient precision and spatial resolution that can provide very important information for researchers, particularly in the fields of plant science and ecotoxicology.

A comparative study of Cu–Ni Alloy using LIBS, LA-TOF, EDX, and XRF

AbstractLASER induced breakdown spectroscopy (LIBS) has been used for the quantitative analysis of Cu–Ni alloy of known composition (75% Cu, 25% Ni) using the one line calibration free-LIBS (OLCF-LIBS), self-calibration-LIBS (SC-LIBS), calibration free LIBS (CF-LIBS), time of flight-mass spectroscopy (TOF-MS), energy dispersive X-ray spectroscopy (EDX) and X-ray fluorescence spectroscopy (XRF). For the LIBS-based studies, the plasma was generated by focusing the beam of a Q-switched Nd:YAG laser (532 nm, pulse energy about 200 mJ, 5 ns pulse duration) while the sample was placed in air at an atmospheric pressure. Plasma temperature about (9500 ± 300) K was calculated by the Boltzmann plot method using the neutral lines of Cu and Ni whereas the electron number density was calculated (2.0 ± 0.5) × 1016 cm−3 from the Stark broadening of an isolated Cu line as well as using the relative intensities of the neutral and singly ionized optically thin lines in the Saha–Boltzmann equation. The elemental compositions determined by different LIBS methods and standard techniques are; OLCF-LIBS (69% Cu and 31% Ni), SC-LIBS (72% Cu and 28% Ni), CF-LIBS (74% Cu and 26% Ni), TOF (74% Cu and 26% Ni), EDX (75% Cu and 24.5% Ni), XRF (73% Cu and 24.7% Ni), and LA-TOF (74% Cu and 26% Ni). It is demonstrated that the CF-LIBS method gives compositions comparable with that determined by LA-TOF, EDX, or XRF, which is also in agreement with the certified reported composition.

A pilot study on the vacuum degree online detection of vacuum interrupter using laser-induced breakdown spectroscopy

Vacuum degree online detection of vacuum interrupter has been a great challenge for decades. In this letter, a novel approach based on laser induced breakdown spectroscopy (LIBS) was proposed to solve this tough problem, which is suitable for non-intrusive, electro-magnetic interference free and remote detection. The spectral lines of Cu, H, N and O elements from the interrupter shield were detected for a large gas pressure range from p = 1 × 10−3 Pa to 1 × 105 Pa. It was found that the spectral intensities of O and H increase monotonically with gas pressure, in contrast the spectral intensity of Cu first decreases slightly and then increases. Their intensity ratios, especially for that of Cu to O, change dramatically and monotonically with the gas pressure when p ⩽ 0.1 Pa, indicating that they can be used for determining the vacuum degree values. Spectral ratio method fundamentally reduces the influences of the possible variation in measuring distance and the laser power fluctuation, making LIBS a promising method for vacuum degree online detection of vacuum interrupters.

Direct determination of Cu by liquid cathode glow discharge-atomic emission spectrometry

In this study, a novel liquid cathode glow discharge-atomic emission spectrometry was developed for the direct determination of Cu in aqueous solutions, in which the glow discharge plasma was produced in the solution between the needle-like Pt cathode and the electrolyte around it. The effects of discharge voltage, solution pH, and the ionic surfactant cetyltrimethylammonium chloride (CTAC) on emission intensities were investigated. The limit of detection (LOD) of Cu was compared with those measured by closed-type electrolyte cathode discharge-atomic emission spectrometry (ELCAD-AES). The results showed that the optimal operation conditions are voltage of 135V, a pH of 1, and addition of 0.15% CTAC. CTAC can enhance the emission intensity and lower the LOD of Cu I. The net intensity of atomic emission lines of Cu I at 324.8nm with 0.15% CTAC improved by 1.5 fold, and the LODs of the Cu at 135V with 0.15% CTAC and without CTAC are 0.019 and 0.234mgL−1, respectively. The analytical capability of Cu in this study is comparable to the closed-type ELCAD-AES, and it satisfied the recommended levels of Cu in the WHO standards for drinking-water quality. This technique can be effectively used for on-line monitoring of metal ions in aqueous samples.

Determination of essential elements in beverages, herbal infusions and dietary supplements using a new straightforward sequential approach based on flame atomic absorption spectrometry.

A simple method based on FAAS was developed for the sequential multi-element determination of Cu, Zn, Mn, Mg and Si in beverages and food supplements with successful results. The main absorption lines for Cu, Zn and Si and secondary lines for Mn and Mg were selected to carry out the measurements. The sample introduction was performed using a flow injection system. Using the choice of the absorption line wings, the upper limit of the linear range increased up to 110mgL-1 for Mg, 200mgL-1 for Si and 13mgL-1 for Zn. The determination of the five elements was carried out, in triplicate, without the need of additional sample dilutions and/or re-measurements, using less than 3.5mL of sample to perform the complete analysis. The LODs were 0.008mgL-1 for Cu, 0.017mgL-1 for Zn, 0.011mgL-1 for Mn, 0.16mgL-1 for Si and 0.11mgL-1 for Mg.

Laser-induced breakdown spectroscopy on metallic samples at very low temperature in different ambient gas pressures

Analysis of metals at very low temperature adopting laser-induced breakdown spectroscopy (LIBS) is greatly beneficial in space exploration expeditions and in some important industrial applications. In the present work, the effect of very low sample temperature on the spectral emission intensity of laser-induced plasma under both atmospheric pressure and vacuum has been studied for different bronze alloy samples. The sample was cooled down to liquid nitrogen (LN) temperature 77K in a special vacuum chamber. Laser-induced plasma has been produced onto the sample surface using the fundamental wavelength of Nd:YAG laser. The optical emission from the plasma is collected by an optical fiber and analyzed by an echelle spectrometer combined with an intensified CCD camera. The integrated intensities of certain spectral emission lines of Cu, Pb, Sn, and Zn have been estimated from the obtained LIBS spectra and compared with that measured at room temperature. The laser-induced plasma parameters (electron number density Ne and electron temperature Te) were investigated at room and liquid nitrogen temperatures for both atmospheric pressure and vacuum ambient conditions. The results suggest that reducing the sample temperature leads to decrease in the emission line intensities under both environments. Plasma parameters were found to decrease at atmospheric pressure but increased under vacuum conditions.