Laser ablation-inductively coupled methods

Raith, A., Hutton, R. C., Abell, I. D., and Crighton, J. (1995). Non-destructive sampling method of metals and alloys for laser ablation-inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectroscopy 10 591-594. 

Several other microanalytical methods in common use potentially have application on soil and sediments section samples. Laser-ablation inductively coupled plasma mass spectrometery (LA-ICP-MS) has been used on soil thin-sections from a controlled field experiment (21) but required special resins in the preparation. There is presently (May 2006) no reported use of this method on archaeological soil samples. Likewise, for extremely fine-resolution studies (i.e. <10 pm) with low minimum detection limits and despite difficult calibration, secondary ion microscopy (SIMS) has a potential role in examining archaeological soil thin sections. At even higher lateral resolutions ( 100 nm) Auger electron spectroscopy (AES) could also be considered for surface (<5 nm deep) analyses. At present however, the use of these methods in soil systems is limited. SIMS has been focused on biochemical applications (22), whereas AES... 

Since the mid-1960s, a variety of analytical chemistry techniques have been used to characterize obsidian sources and artifacts for provenance research (4, 32-36). The most common of these methods include optical emission spectroscopy (OES), atomic absorption spectroscopy (AAS), particle-induced X-ray emission spectroscopy (PIXE), inductively coupled plasma-mass spectrometry (ICP-MS), laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectroscopy (XRF), and neutron activation analysis (NAA). When selecting a method of analysis for obsidian, one must consider accuracy, precision, cost, promptness of results, existence of comparative data, and availability. Most of the above-mentioned techniques are capable of determining a number of elements, but some of the methods are more labor-intensive, more destructive, and less precise than others. The two methods with the longest and most successful histoty of success for obsidian provenance research are XRF and NAA. 

Earlier methods for the determination of uranium in soils employed spectrophotometry of the chromophore produced with arsenic(III) at 655 nm [237 ] and neutron activation analysis [238]. More recently, laser fluorescence [239] and in situ laser ablation-inductively coupled plasma atomic emission spectrometry [240] have been employed to determine uranium in soil. D Silva et al. [241] compared the use of hydrogen chloride gas for the remote dissolution of uranium in soil with microwave digestion. 

The ionization methods reported for IMS included MALDI [41,76-80], Secondary Ion Mass Spectrometry (SIMS) [19, 81-86], Matrix-enhanced (ME)-SIMS [87, 88], Desorption Electrospray Ionization (DESI) [89-99], Nanostructure Initiator Mass Spectrometry (NIMS) [100-102], Atmospheric Pressure Infrared MALDI Mass Spectrometry (AP-IR-MALDI-MS) [103], Laser Ablation-inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) [104-106], Laser Desorption Postionization (LDPI) [107], Laser Ablation Electrospray Ionization Mass Spectrometry (LAESI) [108, 109], and Surface-assisted Laser Desorption/ioniza-tion Mass Spectrometry (SALDI) [110-112], Another method was called probe electrospray ionization (PESI) that was used for both liquid solution and the direct sampling on wet samples. 

Barba and his colleagues sampled the three outcrops of limestone to determine their distinctive signatures. This information was compared to lumps of calcium carbonate found in the finished plaster in the city. The group of scientists used several different techniques to examine the samples. The major element composition of the geological samples was determined by XRF. The major element composition of the lumps was determined by SEM-EDS. Trace element composition was determined by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) to measure the elemental composition of the plaster and the limestone. This methodology is well suited for analyses of very small lumps with microscopic spot sizes. The LA-ICP-MS method is able to analyze a large number of trace and rare earth elements with speed, precision, and high resolution, especially in cases where the major chemical composition does not appear to be particularly distinctive. The instrument worked extremely well for the characterization and determination of the provenance of the Ume plaster source material. 

E. Hoffmann, C. Liidke, J. Skole, H. Stephanowitz, J. Wollbrandt, W. Becker, New methodical and instmmental developments in laser ablation inductively coupled plasma mass spectrometry, Spectrochimica Acta B 57, 1535-1545 (2002)... 

Resano, M., Garcia Ruiz, E., Mihucz, V.G., Moricz, A.M., Zaray, G., Vanhaecke, F. (2007) Rapid screening method for arsenic speciation by combining thin layer chromatography and laser ablation-inductively coupled plasma-dynamic reaction cell-mass spectrometry. Journal of Analytical Atomic Spectrometry, 22,1158-1162. 

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a type of mass spectrometry that is highly sensitive and capable of the determination of a range of metals and several non-metals at concentrations below one part in 10. Together with inductively coupled plasma, it is used as a method to produce ions (ionization) with a mass spectrometer for separating and detecting the ions. ... 

Evans, R. D, andVilleneuve,].Y. (2000). A method for characterization of humic and fiilvic acids by gel electrophoresis laser ablation inductively coupled plasma mass spectrometry... 

Klemm, W. and Bombach, G. (2001) A simple method of target preparation for the bulk analysis of powder samples by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Fresenius J. Anal. Chem., 370(5), 641-6. 

Because ICP-MS with different instrumentations and sample introduction systems (besides solution nebulization, also laser ablation or hyphenated methods, such as HPLC, CE, SPME) is today the most frequently used analytical technique for precise and accurate isotope ratio measurements, the following section will mainly focus on this form of mass spectrometry with an inductively coupled plasma source. 

Laser based mass spectrometric methods, such as laser ionization (LIMS) and laser ablation in combination with inductively coupled plasma mass spectrometry (LA-ICP-MS) are powerful analytical techniques for survey analysis of solid substances. To realize the analytical performances methods for the direct trace analysis of synthetic and natural crystals modification of a traditional analytical technique was necessary and suitable standard reference materials (SRM) were required. Recent developments allowed extending the range of analytical applications of LIMS and LA-ICP-MS will be presented and discussed. For example ... 

Inorganic pigments and lakes (organic dyes bonded to an inorganic support) can be recognized by the ratio of elements in their composition, making elemental analysis an important tool in their identification. EDS may facilitate an initial qualitative analysis, but quantitative analysis and the detection of trace elements are needed to identify the inorganic colorant components. Due to sample size restrictions, the methods that can be employed are limited. The techniques of inductively-coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectroscopy (ICP-OES), and laser ablation ICP-MS are described in the literature (56). 

Use of inductively coupled plasma-mass spectrometry (1CP-MS) coupled to a laser-ablation sample introduction system (LA-ICP-MS) as a minimally destructive method for chemical characterization of archaeological materials has gained favor during the past few years. Although still a relatively new analytical technique in archaeology, LA-ICP-MS has been demonstrated to be a productive avenue of research for chemical characterization of obsidian, chert, pottery, painted and glazed surfaces, and human bone and teeth. Archaeological applications of LA-ICP-MS and comparisons with other analytical methods are described. 

Table 2 Comparison of Isotopic Compositions Measured by Laser Ablation Multiple-Collector Inductively Coupled Plasma Mass Spectrometry and Those Measured by Other Methods...

Pearson N. J., Alard O., Griffin W. L., Jackson S. E., and O Reilly S. (2002) In situ measurement of Re-Os isotopes in mantle sulfides by laser ablation multicollector inductively coupled plasma mass spectrometry anaytical methods and preliminary results. Geochim. Cosmochim. Acta 66, 1037-1050. 

Hi) Methods based on mass spectrometry Spark-source mass spectrometry Glow-discharge mass spectrometry Inductively coupled-plasma mass spectrometry Electro-thermal vaporization-lCP-MS Thermal-ionization mass spectrometry Accelerator mass spectrometry Secondary-ion mass spectrometry Secondary neutral mass spectrometry Laser mass spectrometry Resonance-ionization mass spectrometry Sputter-initiated resonance-ionization spectroscopy Laser-ablation resonance-ionization spectroscopy... 

Solid samples can be introduced into plasmas by vaporizing them with an electrical spark or with a laser beam. Laser volatilization, often called laser ablation, has become a popular method to introduce samples into inductively coupled plasmas. Here a high-powered laser beam, usually a Nd YAG or excimer laser, is directed onto a portion of the solid sample. The sample is then vaporized by radiative heating. The plume of vapor produced is swept into the plasma by means of a carrier gas. 

Thermal ionization. Solid samples are heated to a high temperature (1000-1800 °C) in a vacuum, producing either positive or negative ions. The TIMS method has been used, for example, to obtain records of seawater Sr/ Sr and from biogenic carbonate (e.g. McArthur et al. 2001 Burton Vance 2000). This technique permits precise isotope ratio measurements (external reproducibility <5ppm for Nd/ Nd and Sr/ Sr ratios), but it is restricted to those elements with a relatively low first ionization potential. Inductively-coupled plasma. Sample solutions, or laser ablation products, are ionized in a stream of argon within a plasma torch. The advantage of this technique is that the plasma... 

Shepherd Chenery (1995) pioneered the laser ablation ICP-MS (inductively coupled plasma-mass spectrometry) method of analyzing individual fluid inclusions. An UV laser ablation microprobe is used to drill a hole into a mineral, to reach an inclusion up to 60/zm below the sample surface. For the laser ablation procedure the sample is placed in a modified thermal vacuum cell. The elevated temperature in the ablation cell raises the internal vapor pressure of the inclusion, which causes instantaneous rupture and highly efficient fluid expulsion as the beam breaches the inclusion wall. The vacuum pulls the vaporized fluid into the ICP-MS, where it is analyzed for major and minor ion concentrations. The advantages of the ICP-MS method are the small spot size of the laser (<2 m), allows analysis of small inclusions (> 10/zm) in a variety of minerals (halite, calcite, quartz, and others). A wide range of ions can be analyzed simultaneously, including low concentrations of minor ions. With multicollector ICP-MS, it will be possible to analyze strontium isotopes and other stable isotopes (5 C, S 0, S S) in fluid inclusions. Laser ablation ICP-MS is not as precise as other methods ( 30%) and the results can only be reported as ionic ratios as the volume of an inclusion cannot be determined prior to analysis. However, if the concentration... 

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