Speciation Measurement using Hyphenated ICP-MS

Transcription

1 Speciation Measurement using Hyphenated ICP-MS Ed McCurdy European ICP-MS Specialist Agilent Technologies

2 What is Speciation? Elemental Speciation - the analyses that lead to determining the distribution of an element s particular chemical species in a sample. This may be further associated with oxidation state, organometallic nature or complex form. * *J. A. Caruso, K. L. Sutton, and K. L. Ackley, Elemental Speciation - New Approaches for Trace Element Analysis, Chap. 1, p. 1, Volume XXXIII of COMPREHENSIVE ANALYTICAL CHEMISTRY. Elsevier Publishing, Netherlands, Page 6

3 Why do we need Speciation? Almost all elements form species which can alter their toxicity and mobility Cr III vs Cr VI ; Inorganic As vs Organic As; Humic complexes Some species are specifically used for their toxic (or chemical) properties Organotin Species marine anti-fouling paint; polymer stabilisers; fungicides Organophosphorus Species pesticides; nerve agents Whether natural or anthropogenic, these species can find their way into the environment, food chain etc. Clearly, a there is a requirement for the simple, selective, rapid, sensitive and accurate determination of these species Page 7

4 Speciation Technologies Separation technique coupled with a detector LC, GC, CE UV, MS/MS, MSD, FPD, ECD Offer good separation performance (and sensitivity) Many different detector technologies available many detectors are not so selective give response regardless of active group, or group/element of interest produces unnecessarily complex chromatograms for real samples Page 8

5 Pathways to Elemental Speciation Page 9

6 Suitability of ICP-MS for Chromatography ICP-MS accepts liquids and gases Compatible with flow rates: From <20uL/min to >2mL/min for liquid samples Up to 2L/min for gases, with make-up Ar flow Handles organic LC mobile phases easily Provides high sensitivity for most elements Is capable of rapid data acquisition, so many measurements across a chromatographic peak of only a few seconds Has capability to measure isotopes, so isotope tracer studies and isotope dilution calibration are possible Is extremely selective mass spectrum is almost free from inter-element effects Page 10

7 Practical Coupled Techniques for ICP-MS ICP-MS is suitable for coupling to many separation methods Capillary Electrophoresis (CE) Ion Chromatography (IC) Liquid Chromatography (HPLC) Gas Chromatography (GC) Page 11

8 CE Interface for ICP-MS Instrumentation: Agilent 7500s ICP-MS Agilent 3D CE Cetac CEI-100 interface Photo courtesy of Dr Andreas Prange, GKSS, Germany Page 12

9 CE Interface for ICP-MS CE is extremely low flow (few 100 nl/min), so a make-up liquid flow must be added to carry the eluent to the ICP-MS nebulizer. Very low flow nebulizer and low-volume spray chamber are used for efficient aerosol transport and preservation of chromatographic separation Photo courtesy of Dr Andreas Prange, GKSS, Germany Page 13

10 CE-ICP-MS Operating Conditions Courtesy of Dr Andreas Prange, GKSS, Germany Page 14

11 CE-ICP-MS Performance Rapid separation of 12 species, with excellent signal to noise Courtesy of Dr Andreas Prange, GKSS, Germany Page 15

12 CE-ICP-MS Performance Separation of Metallothioneins CE-ICP-MS is suitable for rapid speciation of elemental species (essentially a liquid chromatography application). A key advantage of CE is that it preserves the molecular structure of high MW compounds, so speciation of high MW molecules, such as metallothionein, is possible. Separation of MT isoforms is shown on the right Courtesy of Dr Andreas Prange, GKSS, Germany Page 16

13 CE-ICP-MS Analysis of MT in Brain Courtesy of Dr Andreas Prange, GKSS, Germany Page 17

14 Ion Chromatography (IC-ICP-MS) Determination of p-block Species Many p-block elements form oxide species which possess carcinogenic properties sulfide/sulfate chloride/chlorate bromide/bromate iodide/iodate As new water treatment procedures are being introduced, (e.g. ozonation), it is becoming increasingly important to have an effective method for the analysis these toxic species Traditional methods (typically standalone Ion Chromatography) may be non-selective and have insufficient detection capability for the low levels at which toxicity occurs Page 18

15 IC-ICP-MS for Speciation Determination of p-block Species Br Intensity ng Br/mL BrO 3 - Br - m/z=79 Se Intensity ng Se/mL Selenite Selenate m/z=78 Dionex IonPac AS12A 11 mm (NH 4 ) 2 CO 3 Flowrate 1.5 ml/min Detector: HP4500 ICP-MS USN + Membrane desolvator 2000 As Intensity ng As/mL Arsenite Arsenate m/z= Retention time [min] Data courtesy of Dr Walter Goessler, U. Graz, Austria Page 19

16 IC-ICP-MS for Speciation Determination of p-block Species P Intensity ng P/mL PO 4 3- m/z=31 Dionex IonPac AS12A 11 mm (NH 4 ) 2 CO 3 Flowrate 1.5 ml/min Detector: HP4500 ICP-MS USN + Membrane desolvator Cl Intensity ng Cl/mL ClO 2 - Cl - ClO 3 - m/z= IO 3 - Dionex IonPac AG12A 3 mm (NH 4 ) 2 CO 3 Flowrate 1.5 ml/min S Intensity ng S/mL SO 4 2- m/z=34 Intensity Retention time (min) I Retention time [min] Data courtesy of Dr Walter Goessler, U. Graz, Austria Page 20

17 Liquid Chromatography (LC-ICP-MS) Determination of just about any elemental species Cr, As, Se, Sn, P, Br, Fe, Pb etc. etc. etc.. Based upon their oxidation state and/or organic complex Page 21

18 LC-ICP-MS nebulizer & spray chamber ICP torch Q-pole mass filter turbo molecular pump turbo molecular pump gas controller rotary pump liquid chromatograph Ar gas Simple coupling meant that LC-ICP- MS was the first hyphenated technique to be seriously investigated. At its simplest, the coupling consists of PFA/PEEK tubing Agilent 1100 LC coupled directly or via a split to 7500 ICP-MS. Remote & sequencing start/stop. Organic mobile phases can be used without problem Page 22

19 Requirements for LC Coupling Sample flow rate from 20uL (capillary LC) to 2mL Most mobile phases contain organic solvents MeOH gradient Acetonitrile Many also contain buffers High salt levels Fast and efficient transfer of eluent to ICP-MS, to minimise degradation of chromatographic resolution Rapid data analysis required though not as rapid as CE or GC, due to broader peaks with LC Software to control LC and ICP-MS in order to allow routine, unattended analysis of sample batches Software to allow combining of LC UV and ICP-MS chromatograms Page 23

20 Sample Introduction for Organics Mass Flow Control for all plasma gases - Cool, Auxiliary, Nebulizer, Blend and optional 5th gas supply for addition of option gas (oxygen) Solvent resistant kit comprising uptake tubing, nebulizer and spray chamber o- rings, isoversinic pump tubing for drain, drain container (separate waste) and torch and T- connector Simple visual optimisation of correct oxygen level to add to decompose organic solvent observation of green C2 emission in plasma Range of narrow injector ID torches (1.0mm to 2.0mm) in place of standard 2.5mm ID torch Page 24

21 Example LC-ICP-MS As Speciation HO As OH HO Arsenious acid HO HO HO As O Arsenic acid HO As O HO Methylarsonic acid HO As O Dimethylarsinic acid Toxic! As + O - As + X- As O As + OH X- Non-Toxic O Arsenobetane Tetramethylarsonium ion Trimethylarsine oxide Arsenocholine O As O O R As O O R? OH OH Dimethylarsinolyribosides OH OH Trimethylarsonioribosides Courtesy of Dr Walter Goessler, U. Graz, Austria Page 25

22 LC-ICP-MS As Speciation Inorganic and Organic As Species 75 As signal (counts) AsIII DMA MMA As 3+ DMA LOD (ppt) R MMA As AsV Common arsenic species required for drinking water analysis HPLC with Agilent 7500 as detector Time (min) Data courtesy of Prof. Joe Caruso, U. Cincinnati, USA Page 26

23 LC-ICP-MS for Speciation Example - Organotin Compounds using HPLC-ICP-MS Organotin compounds are used for a variety of purposes PVC stabilisers agricultural chemicals marine anti-fouling paints (tributyltin - TBT) The small-chain organotin compounds are probably the most toxic. Also the toxicity depends upon the organic moiety some species are highly toxic for mammalian life some species are highly toxic for aquatic life TBT accumulates in sediments and shellfish, so potential for high levels in seafood consumed by humans Page 27

24 LC-ICP-MS for Speciation Determination of Organotin Compounds Sn Sn Sn Cl Cl Trimethyltin chloridetriethyltin chloride Tripropyltin chloride Cl Sn Cl Tributyltin chloride INFORMATION: Sn Cl Triphenyltin chloride Sn Cl Tri(cyclohexyl)tin chloride There are a great many possible organotin compounds - these are examples of just a few of the toxic tri-organotin compounds Species have been manufactured with mono-, di- and tetra- alkylation There are also some natural processes (such as biomethylation) which produce more complex species Page 28

25 LC-ICP-MS for Speciation Determination of Organotin Compounds Determination of six organotin species within 20 min. High ion count obtained for 1mg l -1 (as Sn) solution Intensity Trimethyltin (TMT) Dimethyltin (DMT) Diphenyltin (DPT) Triphenyltin (TPT) Dibutyltin (DBT) Compound Tributyltin (TBT) Detection Limit (pg) % RSD (n=5) DMT TMT DBT TBT DPT TPT Time (s) 50µl injection Data Courtesy of Dr Olivier Donard, U. Pau, France Page 29

26 LC-ICP-MS Stability of Sn-species 20 samples over a 14-hour period Standard check solutions analysed throughout run LC, 7500 ICP-MS Mobile phase: acetonitrile, acetic acid, TFA, water Contamination in vial septum Data courtesy of Raimund Wahlen, LGC Ltd, UK Page 30

27 LC-ICP-MS for Pharmaceutical Samples Analysis of Pharmaceutical Compounds based on Cl, Br & S Abundance Ion (34.70 to 35.70): 000_STD.D Ion (34.70 to 35.70): 002_STD.D Ion (34.70 to 35.70): 003_STD.D Ion (34.70 to 35.70): 004SMPL.D Ion (34.70 to 35.70): 005SMPL.D Ion (34.70 to 35.70): 006SMPL.D Ion (34.70 to 35.70): 007SMPL.D Abundance Ion (78.70 to 79.70): 000_STD.D Ion (78.70 to 79.70): 002_STD.D Ion (78.70 to 79.70): 003_STD.D Ion (78.70 to 79.70): 004SMPL.D Ion (78.70 to 79.70): 005SMPL.D Ion (78.70 to 79.70): 006SMPL.D Ion (78.70 to 79.70): 007SMPL.D Separation and quantification of 3 Cl compounds (left) and 1 Br compound (right) in a mixed sample Standards at 0.0, 0.02, 0.05, 0.1mg Sample (3 replicates) contained 1.0mg of Cl compound 1 and 0.1mg of all other compounds Time--> Time--> Page 31

28 LC-ICP-MS for Pharmaceutical Samples Analysis of Pharmaceutical Compounds based on Cl, Br & S Separation and quantification of S compounds in a mixed sample Standards at 0.0, 0.02, 0.05, 0.1mg and 3 repeats of 1.0mg sample Page 32

29 Gas Chromatography (GC-ICP-MS) Preferred technique for speciation of low boiling point compounds also suitable for high BP compounds, provided high temperature is maintained throughout transfer line Gas phase separation introduces no matrix to the ICP-MS instrument only the analyte is introduced in a clean gas flow Gas phase separations tend to be more rapid than liquid phase separations and peak shape is narrower (improved signal to noise) Page 33

30 Agilent 6890 GC Interfaced to Agilent 7500 First and only commercially available GC-ICP-MS interface - developed in collaboration with National Environmental Research Institute, Tsukuba, Japan Flexible transfer line allows full torchbox x,y,z optimization Xe gas added as I/S and used for optimization Page 34

31 GC-ICP-MS Interface Torchbox Area Demountable torch allows easy maintenance GC capillary heated to injector tip no cold spots GC effluent injected directly into base of plasma Species decomposed to atoms Atoms then ionized and pass into MS Page 35

32 GC-ICP-MS Organotin (OT) Speciation Initial investigations into the coupling of GC to ICP-MS, for the analysis of organotin compounds GC-ICP-MS used to separate and quantify organotin compounds in marine environmental samples of oyster tissue and sediment monobutyltin (MBT) dibutyltin (DBT) tributyltin (TBT) monophenyltin (MPhT) diphenyltin (DPhT) and triphenyltin (TPhT) Page 36

33 GC-ICP-MS OT Sample Preparation Many elements and their species are not in a compatible form for GC separation as they can possess very high boiling points. Such species must be converted into a form compatible for GC Alkylation methylation ethylation propylation etc. This also facilitates elemental GC analysis. ICP-MS gives consistent detection limits, independent of species Detection Limit (pg l -1 Sn) Technique MBT DBT TBT MPhT DPhT TPhT GC-ICP-MS GC-FPD Data Courtesy of Dr Olivier Donard, U. Pau, France Page 37

34 GC-ICP-MS for OT Speciation Determination of Organotin Species 5.0E5 2.5E5 [2] TIC:4-std3.d [Count] MBT 243 sec TPrT 264 sec DBT 287 sec TBT 328 sec Concentration PACS-2 CRM (pg l -1 Sn) Values MBT DBT TBT MPhT DPhT TPhT Certified (300) 1090± ± ± 20* 250± 20* 250± 20* Found 947± ± ± ± ± ± 30 DPhT 425 sec (xxx) = non-certified * = spiked species TPhT 590 sec MPhT 315 sec sec-> Retention time (sec) Data Courtesy of Dr Olivier Donard, U. Pau, France Page 38

35 GC-ICP-MS OT Reproducibility TBT reproducibility test 15 x 1µl injections mass bias check ( 120 Sn/ 117 Sn) Repeats bracketed samples throughout run Abundance Mean Ratio ( 120 Sn/ 117 Sn) Stdev ( 120 Sn/ 117 Sn) %RSD ( 120 Sn/ 117 Sn) 1.68% Time--> Data courtesy of Raimund Wahlen, LGC Ltd, UK Page 39

36 GC-ICP-MS Sn Speciation Anti-bacterial trainer insole Abundance Organotin content: TBT: 16.8ug/g ± 1.4ug/g DBT: 1.6ug/g ± 0.4ug/g TPeT: Detected TIC: msd1.ms EtBu 3 Sn DBT ASE extraction procedure (spiked with 117 Sn enriched species for ID) NaBEt 4 derivatization Extraction into Hexane GC Column - HP5 30m 0.32mm 0.25µm TPeT Et 2 Bu 2 Sn EtPe 3 Sn Time--> Data courtesy of Raimund Wahlen, LGC Ltd, UK Page 40

37 Extending the use of ICP-MS as a GC Detector When used as an elemental detector for gas chromatography, the ICP-MS exhibits all of the advantages of other element-specific GC detectors. Very high selectivity High sensitivity Rapid scan (signal acquisition for multiple elements) In addition, the ICP-MS offers significant advantages over other element specific detectors Wide range of elements and isotopes (only H, He, Ne, Ar and F cannot be directly measured) Very little effect from matrix or co-eluting peaks (signal quenching) Can use hydrogen as GC carrier gas instead of expensive helium Page 41

38 Other Element-Specific Detectors for GC Detector Elements Strengths Disadvantages Electron Capture (ECD) Nitrogen Phosphorous Detector (NPD) Flame Photometric Detector (FPD) Halogens Very high sensitivity Not very selective, poor dynamic range Nitrogen, Phosphorous Good selectivity Difficult to use, moderate sensitivity Tin Good sensitivity Only moderate selectivity Atomic Emission Detector (AED) Chemiluminescence Detector (eg SCD) Most elements Good elemental coverage Only moderate sensitivity, requires multiple injections for multiple element analysis Sulfur, phosphorus Good Sensitivity Very specialized Page 42

39 Example of Detector Specificity/Selectivity: Identification of Bromine-containing Compounds in a Mixture of Pesticides C mass 13 Br mass 79 Br in Pesticide Standard no contribution from other components in non-br compounds Page 43

40 US EPA Method 8085 Compound Independent Elemental Quantification of Pesticides By Gas Chromatography with Atomic Emission Detection (GC-AED) EPA Region 10 Laboratory developed method 8085 which is applicable to over 100 distinct pesticides and herbicides using a single Compound Independent Calibration (CIC) standard EPA is currently evaluating Agilent 7500 GC-ICP-MS as an alternative to GC-AED Advantages of ICP-MS as GC detector for method 8085 superior sensitivity for critical elements single analysis for all elements/compounds ability to use hydrogen carrier multiple isotope information for compound confirmation improved robustness Page 44

41 GC-ICP-MS for Pesticide Analysis Ion (11.70 to 12.70): CICCAL3.D Carbon Ion (30.70 to 31.70): CICCAL3.D Ion (33.70 to 34.70): CICCAL3.D Phosphorus Sulfur Single ion chromatograms for C, P and S, extracted from multielement ICP-MS acquisition Page 45

42 GC-ICP-MS for Pesticide Analysis Ion (34.70 to 35.70): CICCAL3.D Chlorine Ion (78.70 to 79.70): CICCAL3.D Bromine Ion ( to ): CICCAL3.D Iodine Single ion chromatograms for Cl, Br and I, extracted from multielement ICP-MS acquisition Page 46

43 Compound Independent Calibration (CIC) Compound Independent Calibration is a quantitative technique which allows quantification of a compound based on the response of one or more of its elemental components CIC allows measurement of a large number of compounds based on a single simple calibration standard with only a few representative compounds Requirements Compound-independent elemental response vs time Database of known relative retention times and elemental compositions for all target compounds Minimum interferences from matrix or co-eluting compounds Page 47

44 Advantages of Compound Independent Calibration Not necessary to analyze calibration standard for every compound Compound ID based on relative retention time and elemental composition Can use proprietary Retention Time Locking technology and compound retention time database to ensure accurate retention time predictions Response factor based on specific elemental response, independent of compound For example Dursban is 30.3% chlorine by weight. If we measure the weight concentration of the Cl against a different Cl-containing compound, we can calculate the concentration of the Dursban Therefore multi-element, multi-level calibrations can be generated from a single injection of a mixed standard Page 48

45 Compound Independent Calibration for Pesticides & Herbicides, by GC-ICP-MS Compound Concentration (pg/ul) Calib Elements Elemental % Dichlobenil 610 Cl ,4,6-TBA 287 Br 72.5 Ethoprop 39 P, S 12.8, 26.4 DBOB 100 Br 35.1 Phorate 210 P, S 11.9, 36.9 PCNB 169 Cl 60.1 Terbufos 745 P, S 10.8, 33.3 Diazinon 976 P, S 10.2, 10.5 Malathion 107 P, S 9.37, 19.4 Dursban 569 Cl, P, S 30.3, 8.82, 9.15 Ioxynil (methyl ester) 50 I 66 TPP 158 P 50.3 Table 1: Components, concentrations and elemental percentages by weight in 1/10 diluted CIC mix. Page 49

46 Compound Independent Calibration for Pesticides & Herbicides - Sulfur Sulfur Response R 2 = Terbufos Area Malathion Ethoprop Phorate Dursban Diazinon Concentration (pg/ul, S) Page 50

47 Compound Independent Calibration for Pesticides & Herbicides - Phosphorus Phosphorus Response R 2 = Diazinon Area Dursban Terbufos Phorate Malathion Concentration (pg/ul, P) Page 51

48 Preliminary Data Comparison GC-ICP-MS and GC-AED Analyzed low level compound independent calibration standard for US EPA method 8085 Calculated multiple compound elemental response factors and %RSD for each element (S, P, Cl, Br) Compared signal to noise with AED results In all cases, calibration precision (%RSD between multiple calibration compounds) was as good or better than AED (4-8% RSD compared to AED limit of 10-20%) Comparable or better signal for all elements was obtained with 1uL injection by GC-ICP-MS, compared to AED with 15-20uL PTV injection Page 52

49 Compound Independent Calibration (CIC) Factors for Pesticides and Herbicides* Compound Compound Concentration pg/ul RT (min) P response factor Cl response factor Br response factor S response factor I response factor Dichlobenil ,4,6-TBA Ethoprop DBOB Phorate PCNB Terbufos Diazinon Malathion Dursban Ioxynil Ave RF %RSD N/A Dilution corrected average RF(area units/pg) Approximate minimum peak area Approximate DL (element pg/ul or ppb) *Based on 1/10 dilution of GC-AED standard Page 53

50 Analysis of Sulfur Compounds in Gasoline Low sulfur gasoline is important to meet strict air pollution guidelines in many regions Currently, sulfur compounds are identified and quantified by GC with a sulfur specific detector such as SCD (sulfur chemiluminescence detector) or AED (atomic emission detector). Both of these detectors suffer from quenching of sulfur signal from co-eluting carbon compounds Both require very long chromatographic runs to spread the chromatogram and so minimize the overlap from co-eluting compounds GC-ICP-MS has superior tolerance to co-eluting compounds (almost no effect, even from solvent peak), excellent selectivity and sensitivity Page 54

51 GC-ICP-MS Analysis of S Compounds in Gasoline Thiophene 2-methylthiophene 3-methylthiophene 2-ethylthiophene Alkylthiophenes Benzothiophene Methylbenzothiophenes dimethylbenzothiophenes 6 7 Sulfur analysed directly at mass Page 55

52 Analysis of Sulfur Compounds in Gasoline Sulfur in Gasoline by GC-ICP-MS (1/10 split injection) Thiophene 2-methylthiophene 3-methylthiophene 2-ethylthiophene Alkylthiophenes Benzothiophene Methylbenzothiophenes dimethylbenzothiophenes Agilent 6890 GC, Agilent 7500 ICP-MS 30m, 0.32mm ID, 0.25u DB-5 1.0uL split injection of gasoline containing < 300 ppm total sulfur. Oven temp,: 40 C (hold for 3 min.) to 20 C/min Carrier gas: Helium at 2.5 ml/min (constant flow) Split ratio: 10:1 ICP-MS Aux Gas Flow Nitrogen 50 ml/min Sample analysed in about 12 minutes by GC-ICP-MS, compared to 25 minutes with SCD (due to avoidance of co-eluting compounds). GC-ICP-MS still faster, when H 2 used as GC carrier gas Page 56

53 Total Sulfur in Fuels by CIC GC-ICP-MS Sulfur is present as many compounds in fossil fuels Total sulfur is an important regulated component of fuels S emissions are a primary cause of acid rain regulatory requirements demanding rapidly decreasing sulfur concentrations over time Petroleum companies must have S species information, in order to target particular S compounds for removal Compound-independent calibration GC-ICP-MS can be used to measure individual sulfur species and sum to give total sulfur calibrate on a single sulfur compound calculate the area-sum of the sulfur peaks quantify the total area based on a single compound response Page 57

54 Summary CIC and S in Gasoline Agilent 7500 ICP-MS offers alternative detection capability compared to traditional technologies for pesticides analysis at worst, detection limits are comparable to traditional technologies (GC-ICP-MS better for almost all elements) very high selectivity Compound Independent Calibration capability isotopic information/isotope analysis (ID, isotope markers) high flexibility compatible with most chromatographic techniques Applicability to non-metal species analysis in environmental samples and fuels Rapid and very selective determination of sulfur compounds in fuels, providing species information to target sulfur removal and total sulfur concentration Page 58

55 Agilent Plasma Chromatographic Software A comprehensive chromatographic software package for ICP-MS Allows for fully automated chromatographic analysis using the ICP- MS as a detector with real time data analysis Capable of performing real time quality control functions, such as retention time recalibration Data courtesy of Raimund Wahlen, LGC Ltd, UK Page 59

56 Plasma Chromatographic Software - Features Powerful graphics manipulation and display features Advanced integration routines including peak search, shoulder detection and peak smoothing Range of quantification features including weighting and internal standardization Qualifier ion identification for confirmation of target analyte Batch reprocessing of previously acquired chromatographic data Automatic synchronization of chromatograph and Agilent 7500 data acquisition Fully automated chromatography- ICP-MS analysis with real time data analysis and output Real time QC with retention time recalibration Full sample sequence editing capability, including insertion of rush samples Page 60

57 Conclusion Agilent history of expertise in routine LC and GC applications has led to well-integrated chromatography-icp- MS configurations ICP-MS features to assist with setup for routine chromatographic applications low sample flow rate may be requirement for CE and Capillary LC good tolerance to variable organic and salt matrices fast dual mode detection integrated LC-ICP-MS connection kit unique GC-ICP-MS interface application kits for specific LC separations integrated chromatography software allowing routine sequence analysis and calculations, including real-time QC Page 61

58 Future Prospects for Speciation Demand for speciation analysis is here to stay and likely to increase very rapidly in many fields Environment Agriculture Food Clinical/biomedical/pharmaceutical Consumer products Petrochemical ICP-MS is uniquely suitable as a detector for chromatographic separations, due to its speed, sensitivity, selectivity and isotope ratio capability Page 62