Laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS),which is a rapidly developing analytical technique for the analyses of trace elements and isotopes,plays an important role in advancing the study of Earth science,especially with respect to micro-geochemistry.This article reviews the application of LA-ICP-MS in the elemental analysis of solid geological samples.Although LA-ICP-MS has been widely used in the spatial resolution analysis of element compositions and rapid bulk analysis of whole-rock and soil samples,the analysis accuracy is restricted by numerous factors,including the instrumental conditions,the elemental fractionation and matrix effects,the lack of sufficient matrix-matched reference materials,and the strategies for quantitative calibration and sensitivity drift correction.According to the type of samples and the analyte elements,the analysis accuracy can be improved through the optimization of instrument conditions and the adoption of suitable correction strategies and reference materials.
A protocol was established for simultaneous measurements of zircon U-Pb ages and trace elements by LA-ICP-MS at spot sizes of 16 32 μm.This was accomplished by introducing N 2 into ICP to increase the sensitivity.The obtained U-Pb ages for zircon standards GJ-1,TEMORA and SK10-2 are consistent with the preferred values within about 1% uncertainty (2σ) by simple external calibration against zircon standard 91500.Different data reduction softwares could yield different uncertainties for calculation of U-Pb ages.The commercially available program GLITTER4.4 could apply an improper uncertainty calculation strategy,but it may yield artificial high precisions for single analyses.Our trace element analyses indicate that Si is not an ideal internal standard for zircon when calibrated against the NIST glasses.Calibration against the NIST glasses using Si as an internal standard,a systematic deviation of 10% 30% was found for most trace elements including Zr.However,the trace element compositions of zircon can be accurately measured by calibration against multiple reference materials with natural compositions (e.g.,BCR-2G,BHVO-2G and BIR-1G),or calibration against NIST SRM 610 and using Zr as an internal standard.Analyses of two pieces of GJ-1 demonstrate that it is relatively homogenous for most trace elements (except for Ti).
LIU YongShengHU ZhaoChuZONG KeQingGAO ChangGuiGAO ShanXU JuanCHEN HaiHong
