Handbook of Hyphenated ICP-MS Applications 英文版.pdf

Handbook of HyphenatedICP-MS ApplicationsFirst EditionAugust 2007iiTable of ContentsIntroduction4HPLC-ICP-MS HPLC-ICP-MS Introduction7HPLC-ICP-MS for Analysis of Chemical Warfare Agent Degradation Products8Analysis of Glyphosate,Gluphosinate,and AMPA by Ion-Pairing LC-ICP-MS10Analysis of Methyl Mercury in Water and Soil by HPLC-ICP-MS12Determination of Ceruloplasmin in Human Serum by Immunoaffinity Chromatography and SEC-ICP-MS14Iodine Speciation of Seaweed Using Different Chromatographic Techniques With ICP-MS Detection16Determination of Organic and Inorganic Selenium Species Using HPLC-ICP-MS18HPLC-ICP-MS for Preliminary Identification and Determination of Methyl-Selenium Metabolites20 of Relevance to Health in Pharmaceutical SupplementsDetermination of Arsenic Species in Marine Samples Using Cation-Exchange HPLC-ICP-MS23Routine Determination of Toxic Arsenic Species in Urine Using HPLC-ICP-MS25Application of ICP-MS to the Analysis of Phospholipids27Chromium Speciation in Natural Waters by IC-ICP-MS30Multi-Element Speciation Using Ion Chromatography Coupled to ICP-MS32Determination of Trivalent and Hexavalent Chromium in Pharmaceutical,Nutraceutical,and 34 Biological Matrices Using IC-ICP-MSDetermination of Iodine Species Using IC-ICP-MS36GC-ICP-MSGC-ICP-MS Introduction39Analysis of Polybrominated Diphenyl Ether(PBDE)Flame Retardants by GC-ICP-MS40Analysis of Sulfur in Low-Sulfur Gasoline by GC-ICP-MS42Combining GC-ICP-MS and Species-Specific Isotope Dilution Mass-Spectrometry(SS-IDMS)44Determination of Phosphoric Acid Triesters in Human Plasma Using Solid-Phase Microextraction47 and GC-ICP-MSAnalysis of Methylmercury and Inorganic Mercury(Hg2+)in Biological Tissue by Isotopic 49Dilution GC-ICP-MSiiiCE-ICP-MSCE-ICP-MS Introduction52Determination of Roxarsone and Its Transformation Products Using Capillary Electrophoresis 53Coupled to ICP-MSMulti-MSMulti-MS Introduction56Arsenic Metabolites in the Urine of Seaweed-Eating Sheep Using Simultaneous LC-ICP-MS/ES-MS57Determination of Unstable Arsenic Peptides in Plants Using Simultaneous Online Coupling of59ES-MS and ICP-MS to HPLCPhosphorylation Profiling of Tryptic Protein Digests Using Capillary LC Coupled to ICP-MS and ESI-MS62Other Speciation TechniquesOther Hyphenated ICP-MS Techniques Used for Speciation65Analysis of Copper-and Zinc-Containing Superoxide Dismutase by Isoelectric Focusing Gel 66Electrophoresis Laser Ablation-ICP MSA techniques involving ICP-MS are among the fastestgrowing research and application areas in atomic spectroscopy.This is because,by itself,ICP-MS does not give information on thechemical or structural form of the analytes present(since all formsof the analytes are converted to positively charged atomic ions inthe plasma).However,as an excellent elemental analyzer,it alsoperforms as a superb detector for chromatography.HyphenatedICP-MS is achieved through the coupling of the ICP-MS to a sepa-ration techniquenormally a chromatographic separation.In thisway,target analytes are separated into their constituent chemicalforms or oxidation states before elemental analysis(Figure 1).Themost common separation techniques are gas chromatography(GC)and high-performance liquid chromatography(HPLC),whichincludes ion chromatography(IC),but,other separation techniques,such as capillary electrophoresis(CE)and field flow fractionation(FFF),are also used.This handbook specifically addresses the use of ICP-MS as an ele-mental detector for GC,LC,IC,and CE,though the same principleswould apply to other similar techniques.Because of its ability toaccurately distinguish isotopes of the same element,particularlynow that collision/reaction cell(CRC)technology has all but elimi-nated interferences,ICP-MS is also capable of isotope dilution(ID)quantification.Applications of hyphenated ICP-MS fall into the general categorytermed speciation analysis.In all cases,the fractionation device(chromatograph or other)is used to separate the species fromeach other and the matrix,and the ICP-MS is used to detect thespecies of interest.The analyte species may be as simple as ele-mental ions of various oxidation states in solution,or as complexas mixtures of pesticides or biomolecules.In all cases though,theICP-MS is simply acting as an elemental detector.The fractionationdevice serves to separate the various components in the samplebefore detection as well as providing additional information in theform of retention time.Often this combination is sufficient to iden-tify and quantify the target analytes.However where accurateretention time data is not available,analysis of standards or theuse of additional mass spectrometric techniques can provide further confirmation of identification.Elemental speciation is important in many application areas and isbecoming particularly important in the environmental,food,andclinical industries.This is because,for many elements,propertiessuch as those listed below depend on the species or chemicalform of the element present in the sample.Toxicity or nutritional valueEnvironmental mobility and persistenceBioavailability Volatility Chemical reactivityA common example would be the measurement of Cr(VI)(toxic)and Cr(III)(essential nutrient)as opposed to total Cr in environ-mental samples.Similar examples of elemental speciation includeAs(III)/As(V),Se(IV)/Se(VI),and other elements that can exist atdifferent stable oxidation states.Furthermore,arsenic and selen-ium in particular also commonly exist in various organic formswhich can significantly affect the traits listed above.In the case of more complex molecules such as pesticides or biomolecules,the ICP-MS is able to identify and quantify the pres-ence of a particular element or elements in molecular chromato-graphic peaks.When used in conjunction with organic MStechniques,this technique can permit quick screening for mole-cules(peaks)containing specific elements in a complex mixture,prior to analysis by organic MS.With modern,integrated systems and software,simultaneous analysis by ICP-MS andorganic(for example,electrospray ionization ESI)MS is also possible,using a split flow from a single chromatographic device.In addition to the more conventional liquid phase separations(HPLC and IC,for example),ICP-MS is also an excellent detectorfor separations carried out by GC.While other element-specificdetectors exist for GC,none posses the elemental coverage,sensi-tivity,or specificity of ICP-MS.Examples of ICP-MS in molecularspeciation are many and cover a broad variety of applications:Total sulfur and sulfur species in hydrocarbon fuelsOrganotin species in marine sediments and biota,consumergoods,and drinking waterMercury species in fish,industrial discharges,and petroleumprocessingArsenic species in marine algae,food products,and drinking waterBrominated and phosphorus-based flame retardants in consumer goodsPhosphorus and sulfur in biological samplesProtein-and peptide-bound metalsGCHPLCCEOptionalconventionaldetectorInterfaceICP-MSOptional Organic MSSeparationDetectionOtherF Fiig gu ur re e 1 1.Schematic of generic hyphenated system.5Pesticides and herbicidesChemical warfare agentsVolatile organohalides in air samplesIn some cases,it is the presence of the target element that isimportant,(for example Cr(III)or Cr(VI).In other cases,the element or elements are a simple way to identify and quantify amolecule present in a complex mixture(for example using P as ameans of quantifying organophosphorus compounds).This handbook is divided into sections based on the chromato-graphic component of the hyphenated ICP-MS system.Each sec-tion is composed of“application briefs”which outline typical orinteresting applications for that technique.The application briefsare deliberately short,showing only general conditions and outlin-ing results.Specific details for each application can be found inreferenced publications in each section.General RequirementsAll hyphenated ICP-MS systems require that a few simple condi-tions are met.The connecting interface(transfer line)must transmit the fractionated sample quantitatively from the separation system(called a chromatograph from this point forward)to theplasma of the ICP-MS in a form that the plasma can tolerate.The temporal resolution of the sample components must notbe unacceptably degraded.The chromatograph should communicate with the ICP-MS toallow synchronous separation and detection.The ICPMS must be capable of transient signal acquisition atsufficient sampling frequency and over sufficient dynamicrange to accommodate the resolution of the chromatographand the required number of elements or isotopes per peakover their ranges of good rule of thumb for chromatographic detectors applies here.In order to achieve accurate and precise peak integration,approx-imately 10 samples(scans)must be acquired for a typical Gauss-ian peak.Very narrow peaks will require a higher samplingfrequency than wider peaks.As a quadrupole mass spectrometer,the ICP-MS sampling frequency is dependent on the scan speedof the quadrupole,the number of masses scanned,and the dwelltime for each mass.Typically,since the number of elements or isotopes in hyphenated work is small,sufficient scan speed is nota problem.It must be possible to tune the ICP-MS under plasmaconditions similar to those encountered during the chromato-graphic run.Generally,this entails introducing the tuning element(s)via the chromatographic interface.In general,using anICP-MS as a detector for chromatography is a simple matter ofconnecting the outlet of the column to the sample introductionsystem of the ICP-MS.If the sample is gaseous,as in GC,thetransfer line should be passivated and heated to eliminate sampledegradation and condensation and will terminate directly into theICP torch.If the sample is a liquid,the transfer line will likely ter-minate in a nebulizer in order to generate an aerosol compatiblewith the plasma.This may require either a split flow or makeupflow in order to match the chromatographic flow with the nebu-lizer and plasma requirements.Depending on the total sampleflow and choice of nebulizers,the use of a spray chamber may ormay not be necessary.HPLC-ICP-MSHPLC-ICP-MS Introduction7HPLC-ICP-MS for Analysis of Chemical Warfare Agent Degradation Products8Analysis of Glyphosate,Gluphosinate,and AMPA by Ion-Pairing LC-ICP-MS10Analysis of Methyl Mercury in Water and Soil by HPLC-ICP-MS12Determination of Ceruloplasmin in Human Serum by Immunoaffinity Chromatography 14and SEC-ICP-MSIodine Speciation of Seaweed Using Different Chromatographic Techniques With 16ICP-MS DetectionDetermination of Organic and Inorganic Selenium Species Using HPLC-ICP-MS18HPLC-ICP-MS for Preliminary Identification and Determination of Methyl-Selenium Metabolites20 of Relevance to Health in Pharmaceutical SupplementsDetermination of Arsenic Species in Marine Samples Using Cation-Exchange HPLC-ICP-MS23Routine Determination of Toxic Arsenic Species in Urine Using HPLC-ICP-MS25Application of ICP-MS to the Analysis of Phospholipids27Chromium Speciation in Natural Waters by IC-ICP-MS30Multi-Element Speciation Using Ion Chromatography Coupled to ICP-MS32Determination of Trivalent and Hexavalent Chromium in Pharmaceutical,Nutraceutical,34 and Biological Matrices Using IC-ICP-MS Determination of Iodine Species Using IC-ICP-MS IntroductionHigh-performance liquid chromatography(HPLC)is used todescribe any chromatographic technique where analytes dis-solved in a liquid mobile phase are separated based on their inter-actions with the mobile phase and a stationary phase contained ina column.This would include both reverse-and normal-phaseHPLC,size exclusion chromatography(SEC)and ion exchangechromatography.HPLC(or IC)-ICP-MS is used for the analysis ofnonvolatile compounds or ions in solution.The solution can beaqueous,organic,or a mixture of both.It is this flexibility in thechoice of both stationary and mobile phases,including gradienttechniques where the mobile phase changes composition duringthe chromatographic run,which makes HPLC such a powerful sep-aration technique for many applications.As an HPLC detector ICP-MS is the only universal,element-specific detector available forliquid chromatography and,as such,has many applications.Combined with molecular mass spectrometry,ICP-MS can providea powerful screening tool for metallic markers in biological com-pounds.It is also a powerful detector for specific nonmetalsincluding sulfur and phosphorus.Ion chromatography is a specialized form of HPLC designed toseparate ionic species.It is typically used in the separation ofcations(most metal ions in solution),though some metals exist asstable anions(usually oxyanions)in solution as well.The hard-ware is fundamentally similar to HPLC,though allowances aremade for acidic or basic aqueous mobile phases,which coulddamage metal components in the HPLC.High background fromdissolution of metal components can also be a problem.As aresult,ion chromatographs rely on the use of polymeric or passi-vated components that are in contact with the mobile phase.Interfacing the IC to the ICP-MS is quite simple,since typical flowsfor IC are compatible with normal ICP-MS nebulizers.In addition,the sample handling components of the ICP-MS are alreadydesigned for acidic or caustic sample types.Since the ICP-MS isnot a conductivity detector,special techniques to suppress theconductivity of the mobile phase that are required for normal ionchromatography are not necessary with IC-ICP-MS.When used with ion chromatography,ICP-MS can provide positive elemental confirmation in addition to retention time.TheAgilent LC connection kit supplies all the components and documentation necessary to interface an Agilent or other HPLC orIC to the Agilent 7500 Series ICP-MS.Matching the Column Flow to the Nebulizer/SprayChamberMatching the optimum column flow with the optimum nebulizerflow is critical to achieve both efficient separation and samplenebulization.Since the ICP-MS can tolerate nebulizer flow ratesfrom near zero to in excess of 1 mL/minute,the nebulizer is gener-ally selected to match the column flow.Any nebulizer has a rangeof flows over which it produces the highest proportion of finedroplets in the aerosol.This is critical since fine droplets are moreefficiently transported through the spray chamber and atomizedand ionized in the plasma.Therefore,a nebulizer that has an opti-mum flow rate at or near the optimum column flow should beselected.For typical HPLC flows of 100 L/min to 1 mL/min,con-ventional concentric nebulizers,either in glass,quartz,or fluo-ropolymer work very well.At significantly higher flows,some ofthe sample will need to be split off prior to the nebulizer.This canbe accomplished through the use of a low dead volume“Tee”near the nebulizer.In this case,a self-aspirating nebulizer must beused to avoid the need for a peristaltic pump,which would intro-duce unacceptable dead volume.As long as the column flow islarger than the nebulizer self-aspiration rate,there