Copper Emission Lines Research Articles

СПЕКТРОСКОПИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ТЕМПЕРАТУРЫ ЭЛЕКТРОДУГОВОЙ ВОЗДУШНОЙ ПЛАЗМЫ В ВЫСОКОВОЛЬТНОМ ПЛАЗМОТРОНЕ ПЕРЕМЕННОГО ТОКА СО СТЕРЖНЕВЫМИ МЕДНЫМИ ЭЛЕКТРОДАМ И

The article discusses a spectroscopic method for determining the temperature of an electric arc plasma. The results of studies conducted using spectral analysis of copper emission lines are presented. The rationale for the choice of the method and its characteristics is given. This method allows you to determine the electronic component of the temperature. For electric arc plasma, when the principle of local thermodynamic equilibrium is fulfilled, this temperature is approximately equal to the average temperature (energy) of all types of particles. The temperature of the electric arc air plasma calculated by the Boltzmann method is 5100-5450 K.

Spatially and Temporally Resolved Two‐Dimensional Emission Images of Copper Atomic and Ionic Lines in Laser‐Induced Plasma Optical Emission Spectrometry

AbstractThis study features a two‐dimensional spatially and temporally resolved imaging of laser‐induced plasma in copper emission lines, in order to clarify the fundamental mechanism for their excitation/de‐excitations in laser‐induced breakdown spectrometry (LIBS). It was investigated how the plasma excitation was dependent on the type of copper emission lines, different atomic and ionic lines (Cu II 224.700 nm, Cu I 324.754 nm), with the aim to monitor their emission images. A large difference between these emission lines was found in the shape as well as the temporal variation of the emission profiles: while the profile of the Cu II line rapidly disappeared with an expansion of the plasma, that of the Cu I was still observed even at a final stage of the plasma expansion. This result can be explained by their excitation mechanisms. Namely, the excited level for the Cu II line having large excitation energy is mainly populated through a direct collision with an energetic particle, whereas step‐wise de‐excitations from high‐lying excited levels also contribute to the emission of the Cu I line. This result could prove to be useful in the understanding of the background of LIBS.

Effect of Plasma Gas and the Pressure on Spatially and Temporally Resolved Images of Copper Emission Lines in Laser Induced Plasma Optical Emission Spectrometry.

This paper investigated two-dimensional spatial and temporal images of a copper emission line in laser-induced breakdown spectroscopy (LIBS), in order to clarify the excitation/de-excitation processes occurring in a laser-induced plasma. The measurements were carried out under different plasma gases (argon, krypton, helium, and nitrogen), pressure levels (100 - 900 Pa) and delay times (100 - 1000 ns) with the aim of monitoring their effects on the behavior of the copper emission. Depending on the plasma gas type and the pressure level, large differences were found in the plasma shape and temporal intensity evolution of the copper emission profile. Namely, krypton produced the most compact plasma emitting larger intensities, compared to argon and helium, and an increase in the gas pressure made these plasmas to shrink, which could be related principally to the stopping power of the applied gases. Through temporally resolved analysis, the delay profiles could be obtained for each plasma gas, indicating that the helium plasma disappeared more rapidly than the argon and krypton plasmas. It was suggested that the variations in the emission intensity would be determined by interactions between gas particles and highly energetic particles in the plasma breakdown as well as interactions between excited gas particles and copper species during plasma expansion. These insights could prove to be useful in the understanding of the background of LIBS as well as the optimization of its practical applications.

Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

We present a quantitative analysis of a brass alloy using laser induced breakdown spectroscopy, energy dispersive x-ray spectroscopy (EDX) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). The emission lines of copper (Cu I) and zinc (Zn I), and the constituent elements of the brass alloy were used to calculate the plasma parameters. The plasma temperature was calculated from the Boltzmann plot as (10 000 ± 1000) K and the electron number density was determined as (2.0 ± 0.5) × 1017 cm−3 from the Stark-broadened Cu I line as well as using the Saha–Boltzmann equation. The elemental composition was deduced using these techniques: the Boltzmann plot method (70% Cu and 30% Zn), internal reference self-absorption correction (63.36% Cu and 36.64% Zn), EDX (61.75% Cu and 38.25% Zn), and LA-TOF (62% Cu and 38% Zn), whereas, the certified composition is (62% Cu and 38% Zn). It was observed that the internal reference self-absorption correction method yields analytical results comparable to that of EDX and LA-TOF-MS.

Initial Testing of Optical Arc Detector inside 285/300 Fast Wave Antenna Box on DIII-D

Locating arcs within the fast wave current drive system is necessary to improve antenna performance and coupling to the plasma. Previously, there had been no way to observe arcs inside the vacuum vessel in an ICRF antenna on DIII-D. A new diagnostic that uses photomultiplier tubes has been installed for the 2012 run campaign on the 285/300 antenna of the fast wave system. The diagnostic has top and bottom views of the back of the four antenna straps and uses narrow-bandpass visible filters to isolate emission lines of copper (577 nm) and deuterium (656.1 nm). This diagnostic is based on the ORNL filterscope system currently in use on multiple devices. The system will be used to guide fast wave antenna conditioning, plasma operation and provide insight into future antenna upgrades on DIII-D.

Further insights into prepeak emission in pulsed radiofrequency glow discharge

Side-on optical emission measurements, with spatial and temporal resolution, have been carried out on a modified Grimm type pulsed rf glow discharge, using a copper sample and argon as discharge gas. In particular, the early ignition phase of the pulsed discharge, prepeak, and the beginning of the plateau have been electrically characterized and spectroscopically evaluated along the plasma plume for several argon and copper emission lines. Different pulse repetition frequencies have been used while keeping a constant duty cycle of 25%, covering a range from the μs to the ms pulsed GD. In all the cases a spatially extended discharge has been observed during the first 10–20μs of the pulse, when the dc bias voltage has not been fully established yet. During this early phase of the pulse, the species present in the chamber are excited following the amplitude of the voltage symmetrical oscillations, and argon and copper emission can be detected at all the distances evaluated along the plasma axis at delays as short as 4μs. After the first 20μs approximately, the discharge has contracted close to the sample surface, the dc bias voltage has been almost established and the sputtering process is taking place. Emission registered through side-on observation, at positions relatively far from the sample, decreases and then progressively increases to reach a plateau if the voltage pulse lasts long enough. Moreover, the further the detection position is from the sample surface, the later the increase of the copper and argon emission is observed. Therefore transport phenomena involving both argon and copper species are now evidently leading to an estimated average speed of 100m/s.Additionally, end-on optical emission measurements have been carried out to evaluate the prepeak emission from the negative glow region close to the sample surface, and then to compare this emission with that occurring at farther positions (side-on detection experiments). The results have shown that the basis of both prepeaks might be different as the prepeak signal measured using end-on detection peaks around 10μs later than that observed using side-on detection.

Emission Characteristics of Copper Ionic Lines from the 3d95s-3d94p Transition in a Low-Pressure Laser-Induced Plasma

The Emission Characteristic of Copper Ionic Lines Requiring Large Excitation Energies Was Investigated in Low-Pressure Laser-Induced Plasma Spectroscopy (LP-LIPS), when Argon Was Employed as Plasma Gas. The Excited Mechanism of the Ironic Lines Whose Electron Transitions Were Assigned to the 3d95s-3d94p Configuration Was Understood from the Time-Resolved Spectra of Copper. The Emission Intensity of the Copper Emission Lines, Measured in a Time-Resolved Mode, Was Extremely Dependent on the Kind of Copper Lines and the Upper Energy. Generally, their Emission Intensities Dramatically Decreased with the Duration Time, along with the Recombination as Well as the De-Excitation of Copper Ions Requiring Larger Kinetics Energy which Mainly Were Produced in a Hot Breakdown Plasma. The Emission Behavior Excited from the 3d95s-3d94p Transition, such as the Cu II 254.4 nm and the Cu II 276.9 nm Lines, Was Generally Similar to that from 3d94p-3d94s Transition, although their Excitation Energies Were Different. This Effect Would Result from a Common and Dominant Ionization /excitation Mechanism, which Was Collision Energy Transfer from Energetic Particles such as Fast Electrons.

Removal of Fe3+ and Zn2+ from plasma metalloproteins by iron chelating therapeutics depicted with SEC-ICP-AES

The iron chelation therapy drugs desferrioxamine B (DFO) and deferiprone (DFP) are used to treat iron overload patients, but not much is known about their adverse effects on other essential metals in vivo. After the addition of a clinically relevant dose of DFP or an equimolar dose of DFO to human plasma in vitro, the mixtures were analyzed by size exclusion chromatography (SEC) coupled to an inductively coupled plasma atomic emission spectrometer (ICP-AES). Simultaneous detection of the emission lines of copper, iron and zinc allowed the visualization of changes that these drugs exerted at the metalloprotein level. After the addition of DFP, a <10 kDa novel Fe-peak was detected and identified as (DFP)(3)Fe, whereas DFO resulted in the elution of a much smaller amount of Fe in this elution range. In fact, DFP was approximately 8-times more efficient than DFO regarding the removal of Fe from plasma proteins. The addition of both iron chelators also resulted in the elution of a <10 kDa novel Zn-peak. DFP abstracted twice as much Zn from plasma proteins compared to DFO. The identification of one of these peaks as (DFP)(2)Zn establishes a feasible biomolecular basis for the etiology of Zn-deficiency in patients that undergo long-term treatment with these drugs. Our results demonstrate that the analysis of plasma by SEC-ICP-AES can simultaneously provide insight into the efficacy of chelation therapy drugs and their adverse health effects at the metalloprotein level. Thus, SEC-ICP-AES emerges as a useful analytical tool to visualize health-relevant bioinorganic chemistry-related reactions of medicinal drugs in blood plasma in vitro.

The effect of sequential dual-gas testing on laser-induced breakdown spectroscopy-based discrimination: Application to brass samples and bacterial strains

Four Cu–Zn brass alloys with different stoichiometries and compositions have been analyzed by laser-induced breakdown spectroscopy (LIBS) using nanosecond laser pulses. The intensities of 15 emission lines of copper, zinc, lead, carbon, and aluminum (as well as the environmental contaminants sodium and calcium) were normalized and analyzed with a discriminant function analysis (DFA) to rapidly categorize the samples by alloy. The alloys were tested sequentially in two different noble gases (argon and helium) to enhance discrimination between them. When emission intensities from samples tested sequentially in both gases were combined to form a single 30-spectral line “fingerprint” of the alloy, an overall 100% correct identification was achieved. This was a modest improvement over using emission intensities acquired in argon gas alone. A similar study was performed to demonstrate an enhanced discrimination between two strains of Escherichia coli (a Gram-negative bacterium) and a Gram-positive bacterium. When emission intensities from bacteria sequentially ablated in two different gas environments were combined, the DFA achieved a 100% categorization accuracy. This result showed the benefit of sequentially testing highly similar samples in two different ambient gases to enhance discrimination between the samples.

Temporal Variations in the Excitation Temperature of a Laser-induced Argon Plasma Estimated with Copper Emission Lines

A time-resolved spectrometric measurement was conducted to determine temporal variations in the excitation temperature within a single laser plume caused by a Nd:YAG laser plasma. The two-line method using copper atomic lines was employed to estimate the excitation temperature. Two line pairs of copper lines: Cu I 521.82/Cu I 510.55 and Cu I 515.32/Cu I 510.55, were measured by using an Echelle spectrograph equipped with an ICCD detector having a high-speed gating. The excitation temperature was gradually elevated with the progress of the plasma expansion. This result cannot be explained from a direct excitation model in which excited species are principally produced through collisions with energetic particles, but from an indirect excitation model in which second-kind collisions with argon metastables and subsequent step-wise de-excitations produce the excited species. In the latter case, high-lying states of copper atoms are more populated compared to the population expected from the Boltzmann distribution. Temporal variations in the emission intensities of copper atomic lines requiring large excitation energies were also measured, and their emissions remained even in the expansion stage of the laser-induced plasma. This result also implies the over-population of high-lying copper excited levels.

Influence of Dissolution Acid on Emission Intensity in Inductively Coupled Plasma-Optical Emission Spectrometry with Hydrofluoric Acid-Proof Torch

Calibration curves for copper determination were compared using several copper emission lines, when various dissolution acids were employed for sample preparation in inductively coupled plasma-optical emission spectrometry with a conventional and a hydrofluoric acid-proof torch. The conventional torch was composed of a plasma torch with a central tube made of quartz, a concentric-type nebulizer made of quartz and a cyclone-type spray chamber made of glass. On the other hand the hydrofluoric acid-proof torch was composed of a plasma torch with a central tube made of sapphire, a cross flow-type nebulizer made of platinum and a single-pass Scott-type spray chamber made of polytetrafluoroethylene. When sample solutions including nitric acid or a mixture of nitric acid and hydrofluoric acid were introduced to the ICP plasma through the hydrofluoric acid-proof torch, the emission intensities of the copper lines were observed with small fluctuations, leading to a more precise determination of copper. On the other hand, when sample solutions including sulfuric acid or tartaric acid were introduced into the ICP plasma, the emission intensities became smaller with poor analytical precision, independent of the kind of copper lines employed. The reason for this would be a physical interference caused by variations in the physical properties of each acid solution.

窒素‐アルゴン混合ガスを用いたＯｋａｍｏｔｏ‐ｃａｖｉｔｙマイクロ波誘導プラズマの分光特性

An Okamoto-cavity microwave-induced plasma (MIP) with nitrogen-argon mixed gas was investigated to employ an alternative excitation source instead of the conventional nitrogen plasma. The emission intensities of atomic emission lines of copper and iron having small excitation energy were clearly elevated by adding argon gas to the nitrogen plasma, giving the maximum intensity at the argon mixing ratio of 40%. On the other hand, the excitation temperature, which was estimated from Boltzmann plots using Fe I emission lines ranging from 358 to 380 nm, was hardly changed when the amount of argon increased up to 50%. Also, the ionic-to-atomic intensity ratios of calcium, magnesium, and yttrium were not changed so much by mixing the argon gas. These results concerning the excitation temperatue as well as the ionic-to-atomic ratio imply that the excitation characteristics of the N2-Ar MIP are similar to those of the N2 MIP. However, it was observed that the emitting zone of the N2-Ar MIP could be expanded compared to the N2 MIP. Energetic argon species, which are produced through collisions with electrons and nitrogen species, can expand the plasma region due to their smaller cross-section compared to nitrogen molecule species, and then can take part in excitation collisions of analyte atoms at the outer zone of the plasma, leading the increased emission intensities of the analyte atoms.

Comparative Investigation on the Excitation of Copper Emission Lines Between Argon and Helium Spark Discharge Plasmas

The emission intensities and the signal‐to‐background ratios (SBRs) of copper emission lines in the wavelength range 200–360 nm were observed from a medium‐voltage spark discharge plasma when argon or helium was employed as the surrounding gas. The observed copper spectra comprised Cu(I) lines having excitation energy of 3.8–9.3 eV, and Cu(II) lines assigned to three different transitions: 3d 84p–3d 84s transition (excitation energy of 8.2–9.2 eV), 3d 85s–3d 84p transition (13.4–13.6 eV), and the 3d 84d–3d 84p transition (14.2–14.8 eV). The Cu(I) lines have much smaller intensities in the helium plasma compared with the argon plasma, whereas the Cu(II) lines have similar intensities between both plasmas. The SBRs of some ionic copper lines are larger in the helium plasma compared with the argon plasma. Therefore, when an ionic line has to be measured in the analytical applications, the helium plasma should be recommended.

Time-resolved Measurement of Copper Emission Spectrum Excited by a Low-pressure Argon Laser-induced Plasma

A laser-induced plasma generated with a pulsed Nd:YAG laser under evacuated conditions has complicated structures both temporally and spatially. The time-resolved spectra of copper in three different wavelength regions were observed in detail for elucidating the excitation mechanisms of many atomic/ionic copper emission lines. The emission intensities of copper emission lines, measured in a time-resolved mode, were strongly dependent on the kind of copper lines: ionic or atomic lines, and their excitation energies. Generally, copper ionic lines were rapidly decayed and dominantly emitted from the initial breakdown zone, because the copper ions requiring larger excitation energies were produced mainly in the hot breakdown zone. On the other hand, the atomic lines were emitted during prolonged periods, implying that they could also be excited in the expanded plasma zone. The excitation phenomena occurring in the laser-induced plasma could be better understood by analyzing the time-resolved copper spectra.

Excitation Mechanisms of Copper Ionic and Atomic Lines Emitted from a Low‐Pressure Argon Laser‐Induced Plasma

Low‐pressure laser‐induced plasmas generated with a pulsed Nd∶YAG laser have complicated structures both temporally and spatially. The emission characteristics of the plasma are investigated for optimizing the experimental parameters in atomic emission spectrometry. The emission intensities of copper emission lines, measured in a time‐resolved as well as a time‐integrated mode, are strongly dependent on the kind of copper lines, ionic or atomic line, and the excitation energy. Also, the pressure of argon gas is the most important parameter for determining the behavior of these emission lines, including argon lines. Generally, copper ionic lines are dominantly emitted from the initial breakdown zone, because the copper ions are produced mainly in the hot breakdown zone. However, the Cu II 229.44‐nm line is emitted also from the expansion zone of the plasma. It results from an additional excitation process through the charge‐transfer collision particularly effective for the corresponding excited level. In this work, the excitation mechanisms for Cu I, Ar I, and Ar II lines are also discussed. The excitations occurring in the laser‐induced plasma can be well understood by taking the temporal and spatial variations in their intensities into consideration.

Direct optical emission spectroscopy of liquid analytes using an electrolyte as a cathode discharge source (ELCAD) integrated on a micro-fluidic chip

Atomic emission detection of metallic species in aqueous solutions has been performed using a miniaturised plasma created within a planar, glass micro-fluidic chip. Detection was achieved using an Electrolyte as a Cathode Discharge source (ELCAD) in which the sample solution itself is used as the cathode for the discharge. To realise the ELCAD technique within a micro-fluidic device, a parallel liquid-gas flow was set up in a micro-channel and a glow discharge ignited between the flowing liquid sample surface and a metal wire anode. The detection of copper and sodium was achieved, using atmospheric pressure air as a carrier gas, by observation of atomic emission lines of copper at 324 nm, 327 nm, 511 nm, 515 nm and 522 nm and an atomic emission line of sodium at 589 nm using a commercially available miniaturised spectrometer. A total electrical power of less than 70 mW was required to sustain the discharge. A semi-quantitative, absolute detection limit of 17 nmol s(-1) was obtained for sodium with a sample flow rate of 100 microL min(-1) and an integration time of 100 ms in air at atmospheric pressure. The volume required for such detection is approximately 170 nL. Further analysis was performed with an Echelle spectrometer using both argon and air as a carrier gas. The geometry and flow rates used demonstrate the feasibility of integrating such micro-plasmas into other micro-fluidic devices, such as miniaturised CE devices, as a method of detection. The potential for using such micro-plasmas within highly portable miniaturised systems and mu-TAS devices is presented and discussed.

Emission Characteristics of a Low-Pressure Laser-Induced Plasma: Selective Excitation of Ionic Emission Lines of Copper

Under reduced pressures, the plasmas produced by irradiation of a Q-switched Nd:YAG laser have favorable features as an excitation source for solid samples in atomic emission spectrometry, such as relatively low fluctuation of the emission intensity and a high signal-to-background ratio. For the analytical application of low-pressure laser-induced plasma spectroscopy (LP-LIPS), the spectra should be examined regarding the type of emission lines and their relative intensities. Further, information on the excitation mechanism in the plasma could be useful in determining optimum operation conditions of the experimental parameters. Spectrum patterns of LP-LIP are principally determined by the type of the filled gas. Especially, particular ionic lines of Cu are selectively excited when Ar or Ne are employed as the filled gas. This feature seems to be due to the (quasi-) resonance charge transfer collisions between a ground state ion of the Ar or Ne gas and a ground state atom of Cu. The plasma plume expanding after the laser irradiation also becomes an excitation source for sample atoms introduced by laser ablation.

A miniaturized glow discharge applied for optical emission detection in aqueous analytes

DC glow discharge atomic emission spectroscopy of aqueous analytes has been performed in a planar glass microstructure at close to atmospheric pressure using argon as a carrier gas. Sample introduction was achieved using a technique in which the liquid sample itself is employed as the cathode for the glow discharge. To attain sufficient transport of the sample into the discharge region to allow for emission spectroscopy, acidification of the liquid sample is required. Results demonstrate the detection of copper in solution is possible with the observation of five atomic emission lines of copper (at 325 nm, 327 nm, 511 nm, 515 nm and 522 nm). It is hoped that this detection method could be integrated with other micro-fluidic systems as part of a μ-TAS device as well as being useful as a portable, stand-alone detector. However, stability issues will need to be resolved to allow for further optimization and characterization of the device.

Spectral, spatial and temporal characterization of a millisecond pulsed glow discharge: copper analyte emission and ionization

Two-dimensional maps of the spatial distributions of excited and ionized sputtered copper atoms are presented for a millisecond pulsed argon glow discharge. These maps demonstrate the temporal as well as spatial dependence of different excitation and ionization processes over the pulse cycle. Transitions from the low energy electronic states for the atom, characterized by emission such as that at 324.75 nm (3.82→0.00 eV), dominate the plateau time regime at a distance of 2.5 mm from the cathode surface. These processes originate from the electron excitation of ground state copper atoms. Transitions from high-energy electronic states, such as that characterized by emission at 368.74 nm (7.16→3.82 eV), predominate during the afterpeak time regime at a distance of 5.0–6.0 mm from the cathode surface. This observation is consistent with the relaxation of highly excited copper atoms produced by electron recombination with copper ions during the afterpeak time regime. Analyses of afterpeak and plateau intensities for a series of copper emission lines indicate an electron excitation temperature equivalent to 5.78 eV at 0.8 torr and 1.5 W. Temporal profiles exhibit copper ion emission only during the plateau time regime.

Calcul et mesure de la température d'un plasma à l'aide des raies d'émission du cuivre

The use of copper emission lines for temperature measurement in plasma environments is presented. The article features the problems encountered with such a measurement method when used in a stationnary and a non-stationnary plasma. In the first case, we were concerned with the temperature measurements in the jet of a 2 MW industrial plasma torche. The plasma was stationnary and the measurement geometry allowed the use of the Abel inversion method to recover the temperature profiles in the plasma jet. The limitations of the measurement method on the jet boundaries as well as the cooling of the plasma by entrainement of cold air are discussed. In the second case, a non-stationnary plasma in a 1.4 MW electric furnace was studied. This study allowed to feature the role of the detector dynamics as related to the dynamics of the observed medium. The obtained measurements show only a probable temperature in the immediate proximity of the arc. Finally, we conclude on the validity of copper as a tracer and the use of spontaneous emission spectroscopy, an easy method to implement, compared to other sophisticated temperature measurement methods