Laser ablation molecular isotopic spectrometry (LAMIS): current state of the art Alexander A. Bol'shakov, a Xianglei Mao, b Jhanis J. Gonz ´ alez ab and Richard E. Russo * ab 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 10 B/ 11 B ratio determined with confidence of 95% (2s-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 (F 2 -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. 1. Introduction Laser ablation is a process of fast localized removal of the material that is exposed to a pulsed laser beam with nano-, pico- or femtosecond duration of the pulses. In the analytical appli- cations, laser ablation is commonly used as a direct and rapid micro-sampling technique to atomize and ionize a small portion from the analyzed specimen, thus generating a lumi- nous plasma plume. This laser-induced plasma serves as a light and ion source to measure optical emission or mass spectra for the elemental and isotopic analysis of the targeted spot. Laser Induced Breakdown Spectroscopy (LIBS) 1–6 is an optical analysis technology that can instantly acquire atomic emission from ablation in a broad spectral region providing rapid information on elemental composition of the ablated sample. Since only photons need to arrive at and then leave from the target, the target location can be on the surface of solid and liquid samples or inside the sample volume of gases, liquids, and aerosols (near or far from the laser). Laser Ablation Molecular Isotopic Spectrometry (LAMIS) 7 is a similar analytical technique that explores optical spectra of transient molecules produced in ablation plumes in air or buffer gases for rapid isotopic analysis of the samples. LAMIS measures molecular emission as the plasma cools, when free molecules are formed in the plasma aerglow via several mechanisms including radiative and three-body association of atoms and recombining ions. The isotopic constituents produce the electronically, vibrationally and rotationally excited isotopologues of dimers, oxides, nitrides or halides in plasma reactions between the atomized matter from the sample and the ambient atmosphere. Isotopologue molecules have isotopic spectral shis that are considerably larger than those in atomic spectra, and therefore the former can be measured with a general purpose spectrom- eter. Molecular quantum energy levels, particularly the vibra- tional and rotational components, strongly depend on mass difference between isotopes, while the electronic energy is primarily determined by the Coulomb eld but signicantly less dependent on the mass of nuclei. 7 Consequently, molecular transitions involving change of vibrational and rotational states can exhibit up to several orders of magnitude larger isotopic shis than atomic transitions, which are purely electronic in nature. Larger isotopic shis in LAMIS signicantly relax requirements on spectral resolution relative to LIBS. The necessity of high resolution is the main reason why LIBS is generally not utilized for isotopic detection. Even in theory, the isotopic splitting in atomic spectra of the majority of elements cannot be resolved in LIBS emission, since these splittings are a Applied Spectra, Inc., 46665 Fremont Boulevard, Fremont, CA 94538, USA b Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA. E-mail: rerusso@lbl.gov Cite this: J. Anal. At. Spectrom. , 2016, 31, 119 Received 30th July 2015 Accepted 13th October 2015 DOI: 10.1039/c5ja00310e www.rsc.org/jaas This journal is © The Royal Society of Chemistry 2016 J. Anal. At. Spectrom., 2016, 31, 119–134 | 119 JAAS TUTORIAL REVIEW Published on 02 November 2015. Downloaded on 31/12/2015 04:44:05. View Article Online View Journal | View Issue