Determination of elements in situ in green leaves by laser ablation ICP-MS using pressed reference materials for calibration

摘要

Laserablation(LA)wasusedwithdoublefocusingsectorfieldinductivelycoupledplasmamassspectrometry(ICP-MS)fordirectelementalanalysisofgreenleavesfromsevenspeciesofdesertplants.Pressedleafstandards(n=7)wereusedasmatrixmatchedstandardsforcalibrationandqualityassurance.Nineelements(Mg,Ca,Mn,Cu,Sr,Cd,Ba,HgandPb)weredeterminedinlowmassresolution(m/Δm≈400).Datawascollectedforthreeablationlinescansstartingfromnearthestemtothetipoftheleaf.The213nmlaserablationsystemwasoperatedatthefullenergysetting(100%),witharepetitionrateof20Hz,aspotsizeof100μm,andascanrateof50μmmin?1.Pressedcellulosewasusedforestimatingdetectionlimits,whichwerefoundtovarybetween0.04and26μgg?1forPbandCa,respectively.Resultssuggestthatthecalibrationapproachisfeasibleforsomeelements(Mg,Ca,Mn,Cu,Sr,Cd,Ba)butproblematicforothers(Pb,Hg).Althoughsomewhatelementdependent,desertwillow,autumnsageandbrittlebushtendedtohavethehighestconcentrationsoftheelementsmonitored.Overall,LA-ICP-MSisausefulmethodforquantifying(insitu)thedistributionofmanyelementsinplantleaves...