Surface analysis using ionic spectrometries

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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