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[en] The aim of this work was to demonstrate that an archaeological ceramic piece has remained buried underground in the same stratum for centuries without being removed. For this purpose, a chemometric model based on Principal Component Analysis, Soft Independent Modelling of Class Analogy and Linear Discriminant Analysis classification techniques was created with the concentration of some selected elements of both soil of the stratum and soil adhered to the ceramic piece. Some ceramic pieces from four different stratigraphic units, coming from a roman archaeological site in Alava (North of Spain), and its respective stratum soils were collected. The soil adhered to the ceramic pieces was removed and treated in the same way as the soil from its respective stratum. The digestion was carried out following the US Environmental Pollution Agency EPA 3051A method. A total of 54 elements were determined in the extracts by a rapid screening inductively coupled plasma mass spectrometry method. After rejecting the major elements and those which could have changed from the original composition of the soils (migration or retention from/to the buried objects), the following elements (25) were finally taken into account to construct the model: Li, V, Co, As, Y, Nb, Sn, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Au, Th and U. A total of 33 subsamples were treated from 10 soils belonging to 4 different stratigraphic units. The final model groups and discriminate them in four groups, according to the stratigraphic unit, having both the stratum and soils adhered to the pieces falling down in the same group.
[en] Resonance Ionization Mass Spectrometry (RIMS) is being developed to measure thorium isotopes from geological samples. These measurements, in conjunction with uranium measurements by thermal ionization, permit geochronological dating in the timescale of 10,000 to 350,000 years. (Author)
[en] In this paper, we discuss the use of Resonance Ionization Mass Spectrometry (RIMS) to perform isotopically selective saturation spectroscopy of lutetium isotopes. Utilizing this technique, it is shown that accurate measurements of the relative frequencies of hyperfine (HF) components for different isotopes easily can be made without the need for an isotopically enriched sample. The precision with which the HF splitting constants can be determined is estimated to be ∼5 times greater than in previous work
[en] This paper describes advances in isotopic measurements that have been made with an inductively coupled plasma source magnetic sector multiple collector mass spectrometer (MC-ICP-MS) and presents results of new experiments aimed at further evaluating the instrumental capability as well as the correction technique for the mass discrimination effects. The ability to correct for the mass discrimination effect using a second element of similar mass and very high sensitivity for elements that are otherwise difficult to ionize gives this instrument major advantages over other conventional techniques for isotopic measurements. The isotopic data obtained by MC-ICP-MS clearly demonstrate potential as a new technique to produce precise and reproducible isotopic data for the elements that are difficult to measure by thermal ionization mass spectrometry (TIMS). (author)
[en] Monitoring resonant optogalvanic responses in hollow cathode discharge lamp associated with the absorption of laser photons have been use effectively as wavelength calibrator in laser spectroscopy. A simple detection circuit but produces high precision measurement is used to calibrate the dye laser wavelength. Only a fraction of the laser output from an Nd:YAG laser pumped, grazing incidence dye laser is required to map out the optogalvanic spectrum from a commercially available hollow cathode discharge tube. Some results on optogalvanic spectrum and its direct wavelength calibration in resonance ionization mass spectroscopy (RIMS) is briefly discussed. Simple analysis on noise which lead to detection limit in optogalvanic spectroscopy is also presented
[en] The main application of the inductively coupled plasma (ICP) today is in atomic emission spectroscopy (AES), as an excitation spectrochemical source, although uses of an ICP for fluorescence as just an atomizer, and specially for mass spectrometry, as an ionization source, are rocketing in the last few years. Since its inception, only a quarter of a century ago, ICP-AES has rapidly evolved to one of the preferred routine analytical techniques for convenient determination of many elements with high speed, at low levels and in the most varied samples. Perhaps its comparatively high kinetic temperature (capable of atomizing virtually every compound of any sample), its high excitation and ionization temperatures, and its favourable spatial structure at the core of the ICP success. By now, the ICP-AES can be considered as having achieved maturity in that a huge amount of analytical problems can be tackled with this technique, while no major or fundamental changes have been adopted for several years. Despite this fact, important driving forces are still in operation to further improve the ICP-AES sensitivity, selectivity, precision, sample throughput, etc. Moreover, proposals to extend the scope of the technique to traditionally elusive fields (e.g. non-metals and organic compound analysis) are also appearing in the recent literature. In this paper the 'state of the art', the last developments and the expectations in trying to circumvent the limitations of the ICP-AES (on the light of literature data and personal experience) are reviewed. (author)
[en] In this communication, we present the development of the first double-pulse micro-LIBS (DP-μLIBS) instrument for three-dimensional compositional mapping of materials. The system allows for high-resolution three-dimensional scanning of materials; its advantages with respect to conventional single-pulse micro-LIBS systems are described and discussed. As a test example, we analyzed three Euro coins to show the performances of the system on homogeneous samples (20 Eurocents), heterogeneous samples (1 Euro) and layered samples (5 Eurocents). DP-μLIBS cannot provide isotopic information and has, typically, limits of detection for the elements of interest much higher with respect to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). However, when the isotopic information and the extreme sensitivity to trace elements is not be necessary, the results obtained show that DP-μLIBS can be a viable alternative to LA-ICP-MS for the acquisition of high resolution three-dimensional compositional maps. - Highlights: • We present the development of the first DP-μLIBS instrument for 3D compositional mapping. • Its advantages with respect to conventional SP-μLIBS systems are described and discussed. • Three Euro coins were analyzed, to show the performances of the system. • The results obtained show that in some application DP-μLIBS can be a viable alternative to LA-ICP-MS.
[en] Resonant Laser Ablation (RLA), which combines Laser Ablation (LA) and Resonance Ionization Spectroscopy (RIS) simultaneously with a single laser, can be used as a simple analytical technique of trace elements with high sensitivity and elemental (isotopic) selectivity for solid samples. However, the elemental selectivity falls off in the higher laser power range because of an increase of an ion yield produced non-resonantly in laser ablation process. To enhance an ion yield produced through the resonant ionization process, the incident laser is split into two beams for LA and RIS, respectively. In the present study, we have developed a simple theoretical model to simulate the RLA process and checked the validity of the model by analyzing some experiments to detect a trace of Al. The dependence of the elemental selectivity and the detection limit on the incident laser power is mainly discussed to optimize the trace element analytical technique with RLA
[en] The review is devoted to the major advances in laser sampling. The advantages and drawbacks of the technique are considered. Specific features of combinations of laser sampling with various instrumental analytical methods, primarily inductively coupled plasma mass spectrometry, are discussed. Examples of practical implementation of hybrid methods involving laser sampling as well as corresponding analytical characteristics are presented. The bibliography includes 78 references
[en] ICP (Inductively Coupled Plasma) generators at atmospheric pressure have quite widespread since thirty years. They are useful for elementary analysis, either for optical emission spectroscopy or for mass spectroscopy. Plasma know how is described. For both spectroscopies, the best choice is argon plasma, emitted by a HF (high frequency) inductive source, at a 1 to 2.5 kW power. Then the analytical properties are detailed. (D.L.). 8 refs., 3 figs., 1 tab., 1 photo