Mid-IR enhanced laser ablation molecular isotopic spectrometry (original) (raw)
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Laser Ablation Molecular Isotopic Spectrometry: Parameter influence on boron isotope measurements
Laser Ablation Molecular Isotopic Spectrometry (LAMIS) was recently reported for optical isotopic analysis of condensed samples in ambient air and at ambient pressure. LAMIS utilizes molecular emissions which exhibit larger isotopic spectral shifts than in atomic transitions. For boron monoxide 10BO and 11BO, the isotopic shifts extend from 114 cm−1 (0.74 nm) to 145–238 cm−1 (5–8 nm) at the B 2Σ+ (v=0)→X 2Σ+ (v=2) and A 2Πi (v=0)→X 2Σ+ (v=3) transitions, respectively. These molecular isotopic shifts are over two orders of magnitude larger than the maximum isotopic shift of approximately 0.6 cm−1 in atomic boron. This paper describes how boron isotope abundance can be quantitatively determined using LAMIS and how atomic, ionic, and molecular optical emission develops in a plasma emanating from laser ablation of solid samples with various boron isotopic composition. We demonstrate that requirements for spectral resolution of the measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra. Sensitivity can be improved by using a second slightly delayed laser pulse arriving into an expanding plume created by the first ablation pulse.
Matrix effects in laser ablation molecular isotopic spectrometry
Spectrochimica Acta Part B: Atomic Spectroscopy, 2014
ABSTRACT Recently, it has been shown that laser-induced breakdown spectroscopy (LIBS) can be used for the detection of isotopes of elements via isotopic shifts in diatomic species in a technique known as laser ablation molecular isotopic spectrometry (LAMIS). While LAMIS works quite well for isotopic analysis of pure compounds under optimal conditions, it is desirable for it to be applicable for a variety of compounds and matrices. However, the LIBS plasma emission associated with LAMIS depends on several parameters, including the applied electric field of the laser pulse, the physical properties of the material being investigated, and the presence of additional elements other than the element of interest. In this paper, we address some of the pitfalls arising from these dependencies when using LAMIS for determination of the relative isotopic abundance of boron-containing materials with varying chemical matrices.
Laser Ablation Molecular Isotopic Spectrometry
A new method of performing optical isotopic analysis of condensed samples in ambient air and at ambient pressure has been developed: Laser Ablation Molecular Isotopic Spectrometry (LAMIS). The technique uses radiative transitions from molecular species either directly vaporized from a sample or formed by associative mechanisms of atoms or ions in a laser ablation plume. This method is an advanced modification of a known atomic emission technique called laser-induced breakdown spectroscopy (LIBS). The new method — LAMIS — can determine not only chemical composition but also isotopic ratios of elements in the sample. Isotopic measurements are enabled by significantly larger isotopic shifts found in molecular spectra relative to atomic spectra. Analysis can be performed from a distance and in real time. No sample preparation or pre-treatment is required. Detection of the isotopes of hydrogen, boron, carbon, and oxygen are discussed to illustrate the technique.
Laser Ablation Molecular Isotopic Spectrometry (LAMIS): current state of the art
Laser Ablation Molecular Isotopic Spectrometry (LAMIS) is a direct and rapid technique that measures optical emission in laser-induced plasmas for isotopic analysis. LAMIS exploits relatively large isotope shifts in spectra of transient molecular isotopologues formed in laser ablation plasma. LAMIS can be performed without sample preparation at atmospheric pressure in open air or inert buffer gases. A spectrometer with modest spectral resolution can be suitable for both LIBS and LAMIS techniques, and thus elemental and isotopic measurements can be accomplished on the same instrument. To date, detection of several isotopes (H, B, C, N, O, Cl, Sr, and Zr) in laser ablation plumes was demonstrated. Precision of quantitative LAMIS measurements was within 9‰ for the 10B/11B ratio determined with confidence of 95% (2σ-interval). Simultaneous determination of isotopes of different elements was shown to be physically possible, while determination of several isotopes of the same element was successfully demonstrated (Sr, Zr). The studies on double-pulse LAMIS and femtosecond LAMIS indicated further prospects for improving accuracy and sensitivity in this technique. A possibility of semi-quantitative isotopic analysis at distances up to 7.8 m without using calibration standards was demonstrated. The latter technique was named as Femtosecond Filament-induced Laser Ablation Molecular Isotopic Spectrometry (F2-LAMIS). Application of LAMIS in industrial, laboratory, and field operations is possible; and such measurements can be realized at a standoff distance to the sample.
Boron isotope enrichment in nanosecond pulsed laser-ablation plume
Applied Physics A: Materials Science & Processing, 2003
Boron isotopic enrichment is observed in the laser ablation of B 4 C target using nanosecond (ns) wide 532 nm laser beam of a Nd-YAG laser. B 10 /B 11 ratio of 0.9 against the natural abundance of 0.25 is obtained at a laser power density of 8 × 10 8 W/cm 2 (fluence of 6.4 J/cm 2). The enrichment as a function of laser power density is demonstrated using a quadrupole mass spectrometer. Apart from higher enrichment factor, only singly charged ions are found in the laser plume from the B 4 C target, in contrast to the multiply charged ions from the BN target reported in a recent report using femtosecond (fs) laser pulses. This study indicates the possibility of using less expensive, widely used ns lasers, which can also yield a higher throughput per pulse than a fs laser for isotope enrichment.
Laser Ablation Molecular Isotopic Spectrometry for rare isotopes of the light elements
Spectroscopy, Vol. 29, No.6, pp. 30-39 (2014), 2014
Laser ablation molecular isotopic spectrometry (LAMIS) involves measuring isotope-resolved molecular emission. Measurements of several key isotopes (hydrogen, boron, carbon, nitrogen, oxygen, and chlorine) in laser ablation plumes were demonstrated. Requirements for spectral resolution of the optical detection system could be significantly relaxed when the isotopic ratio was determined using chemometric regression models. Multiple applications of LAMIS are anticipated in the nuclear power industry, medical diagnostics and therapies, forensics, carbon sequestration, and agronomy studies.
Analytical Chemistry, 2013
Laser ablation molecular isotopic spectrometry (LAMIS) recently was reported for rapid isotopic analysis by measuring molecular emission from laser-induced plasmas at atmospheric pressure. This research utilized the LAMIS approach to study C 2 molecular formation from laser ablation of carbon isotopic samples in a neon gas environment at 0.1 MPa. The isotopic shift for the Swan system of the C 2 Δν = 1 band was chosen for carbon isotope analysis. Temporal and spatial resolved measurements of 12 C 2 , 12 C 13 C, and 13 C 2 show that C 2 forms from recombination reactions in the plasma. A theoretical simulation was used to determine the temperature from the molecular bands and to extract the isotopic ratio of 12 C/ 13 C derived from 12 C 2 , 12 C 13 C, and 13 C 2 . Our data show that the ratio of 12 C/ 13 C varies with time after the laser pulse and with distance above the sample. 12 C/ 13 C deviates from the nominal ratio (2:1) at early times and closest to the sample surface. These measurements provide understanding of the chemical processes in the laser plasma and analytical improvement using LAMIS.
Journal of Analytical Atomic Spectrometry, 2020
Thank you very much for agreeing to review this manuscript for Journal of Analytical Atomic Spectrometry (JAAS) JAAS is the central journal for publishing innovative research on fundamentals, instrumentation, and methods in the determination, speciation and isotopic analysis of (trace) elements within all fields of application. This includes, but is not restricted to, the most recent progress, developments and achievements in all forms of atomic and elemental detection, isotope ratio determination, molecular analysis, plasma-based analysis and X-ray techniques.
Laser ablation molecular isotopic spectrometry of carbon isotopes
Quantitative determination of carbon isotopes using Laser Ablation Molecular Isotopic Spectrometry (LAMIS) is described. Optical emission of diatomic molecules CN and C2 is used in these measurements. Two quantification approaches are presented: empirical calibration of spectra using a set of reference standards and numerical fitting of a simulated spectrum to the experimental one. Formation mechanisms of C2 and CN in laser ablation plasma are briefly reviewed to provide insights for implementation of LAMIS measurements. A simulated spectrum of the 12C2 Swan system was synthesized using four constituents within 473.5‒476.5 nm. Simulation included three branches of 12C2 (1-0), branches R(0-0) and R(1-1), and branch P(9-8) of 12C2. Spectral positions of the tail lines in R(0-0) and R(1-1) were experimentally measured, since they were not accurately known before. The Swan band (1-0) of the isotopologue 13C12C was also simulated. Fitting to the experimental spectrum yielded the ratio 13C/12C = 1.08% in a good agreement with measurements by isotope ratio mass spectrometry. LAMIS promises to be useful in coal, oil and shale exploration, carbon sequestration monitoring, and agronomy studies.