PerkinElmer: A Novel High Sensitivity Mass Spectrometric Detector for Gas Chromatography
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A new quadrupole MS system has been designed for GC applications that increases signal to noise performance and hence detection limits to levels not previous seen with such systems. This performance has been obtained through the development of two new critical components: a new ion source design and a new electron multiplier detector design. The ion source has been designed for use in both EI and CI modes of operation with the simple exchange of just a few source parts. The source design provides for easy removal with a 180° twist that also ensures a positive seal on reinstallation, preventing air leaks from occurring. The self-aligning nature of the twist mechanism assures positive contact with all electrical connections preventing failures from intermittent contacts. The source has been designed using a minimum number of parts that require no tools to disassemble, clean and reassemble. Both these features provide for a shorter maintenance time and faster pumpdown resulting in shorter downtime for maintenance and/or column change. The new detector comprises four critical components: • Ion Deflector—Turns the ions, filtering off any noise and passing only ions of interest to the high-voltage conversion dynode for improved signal to noise ratio and better detection limits. • Electron Multiplier—Discrete dynode design outperforms and outlasts low-cost continuous dynode systems. • Constrictor Lens—Further focuses the ion beam as it leaves the analyzing quadrupole. • Patented High-Voltage Conversion Dynode—Optimizes electron multiplication for greater sensitivity and longer lifetime. These features provide better response in full and single ion monitoring and in combination (SIFI) applications. We will illustrate the application and performance of the new detector with classical applications such as the EPA method 8270 for semi-volatile pollutants in soil and water
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PerkinElmer: A Novel High Sensitivity Mass Spectrometric Detector for Gas Chromatography
- 1. A novel high sensitivity mass spectrometric detector for gas chromatography Andrew Tipler, Frank De Lorenzo, Ruben Garnica, Yury Kaplan, Dawn May PerkinElmer Inc., Shelton Ct 1 © 2009 PerkinElmer
- 2. Goals Present a GC/MS with novel ion source and detector design. Provide experimental results from both environmental and food applications. 2
- 3. Introduction • Overview of general analytical system • Ion source • Detector • Analytical results • Performance standard - OFN • SVOA by 8270D (environmental application) • Pesticides by AOAC 2007.1 (food application) • VOC by 8260C (environmental application) • Conclusions 3
- 4. The GC/MS System Clarus 680 GC SQ 8 MS 4
- 5. The GC/MS System Clarus 680 GC Dual channel GC Low thermal mass oven PPC gas control Programmable split/splitless injectors SQ 8 MS 5
- 6. The GC/MS System Clarus 680 GC SQ 8 MS Dual channel GC Heated transfer line Low thermal mass oven Removable ion source PPC gas control Quadrupole with pre-quad filters Programmable split/splitless injectors Noise cancelling detector optics Electron multiplier based detection 6
- 7. SMARTsource – Quick Change Capabilities Novel grooved cam-locked design for quick removal and insertion improves usability and 7
- 8. Removal and Insertion of the Source With No Tools 8
- 9. Ion source yoke with quick connect electronics Yoke receptacle Guide pins Quick Connect plug 9
- 10. Quick change ion source – flame retardant analysis From a single sample… …analysis by Positive CI… …followed by EI… …without the need to reprep the sample. 10
- 11. Quick change ion source 11
- 12. Electron Multiplier based ion detector Noise reducing detector design • Novel ion optics • Advanced material • Discrete EM for max gain Benefits • Enhanced sensitivity • Operational flexibility 12
- 13. EM Detector – Design Grounded entrance plate 270º ion path Conversion Dynode Advanced Ion Optics Discrete electron multiplier 13
- 14. EM Detector – Function Unwanted charged ions filtered Neutrals filtered 14
- 15. Clarifi Detector – Ion Simulation 15
- 16. Setting EM Voltage – Wide Functional Range 6.0E+07 5.0E+07 Intensity of Naphthalene 4.0E+07 (m/z = 128) 3.0E+07 2.0E+07 1.0E+07 0.0E+00 1160 1260 1360 1460 1560 1660 1760 1860 Multiplier (V) 16
- 17. Analytical Results Test Standard (Octafluoronaphthalene) 17
- 18. Maximum Sensitivity – OFN Standard , 09-May-2011 + 14:11:36 648N1042202_1pg ofn 17 1: Scan EI+ 272 100 2.03e6 S/N:RMS=1176.27 % Sensitivity Measurements 0 • 1 pg/ L OFN 648N1042202_1pg ofn 16 100 S/N:RMS=1148.58 1: Scan EI+ 272 • 1 L pressure pulse injection • Scanning m/z = 50 – 300 2.03e6 % 0 648N1042202_1pg ofn 15 1: Scan EI+ S/N:RMS=1526.68 272 100 2.03e6 % > 800:1 s/n (RMS) 0 Time 4.75 5.75 6.75 7.75 8.75 18
- 19. Analytical Results SVOA by GC/MS EPA 8270D 19
- 20. SVOA by GC/MS Standard US EPA Method 8270D • Extraction of solid waste samples (among others) • Analysis by liquid injection GC/MS • Tens to hundreds of target compounds Experiment Focus • Optimize EM setting for maximum dynamic range Method • Standard EPA 8270D methodology followed • Mega Mix with internal standards 20
- 21. SVOA by GC/MS – example chromatogram (40 g/mL) Scan EI+ 63 TIC 100 43 32 36 23 57 58 62 54 53 25 46 60 20 27 28 71 52 29 38 2 67 72 47 12 24 56 59 48 50 % 8 13 68 69 18 41 51 10 15 65 66 31 16 55 17 30 1 0 Time 3.00 5.00 7.00 9.00 11.00 13.00 15.00 17.00 19.00 21
- 22. SVOC by GC/MS – Calibration Results (1-150 g/mL) RT # Compound Average RRF RRF %RSD (min) 1 Pyridine 3.09 0.2 8.98 2 Aniline 4.44 1.2 13.16 4 N-Nitrosodimethylamine 4.45 0.1 10.3 26 Naphthalene 6.24 1.1 9.63 27 Hexachlorobutadiene 6.39 0.2 10.38 42 2,4- Dinitrophenol 8.60 0.1 8.17 49 Fluorene 9.15 1.3 11.93 57 Pentachlorophenol 10.18 0.1 8.01 64 Pyrene 12.26 1.2 9.62 67 Benzo[a]anthracene 13.89 1.0 11.8 70 Bis (2-ethylhexyl) phthalate 13.98 0.6 17.47 74 Benzo[a]pyrene 16.29 1.0 9.46 Average %RSD ~ 11% (all 78 compounds) 22
- 23. Analytical Results Pesticides by GC/MS AOAC 2007.1 23
- 24. Pesticides in Food – AOAC 2007.1 AOAC 2007.1 • Association of Analytical Chemists • Pesticides in grapes, lettuces, tomatoes, oranges • QuEChERS extraction (not performed) Target • Meet <10 ng/g method specification using SIFI SIFI = simultaneous selected ion full scan Success • Good Chromatography • +24 compounds meeting specs 24
- 25. Pesticides in Food – AOAC 2007.1 Retention Analyte Time 14.80 Methamidophos 3.40 100 110411_Pest_010 Dichlorovos (DDVP) 3.49 3.49 Omethoate 6.12 15.71 Demeton-s-methyl 6.38 Dimethoate 7.36 6.12 Dichloran 7.39 Tefluthrin 8.13 Tolclofos-methyl 8.92 Pirimiphos-methyl 9.30 17.61 11.35 Chlorpyrifos(Dursban) 9.65 Pendimethalin 10.26 % Methidathion 10.85 14.98 18.80 Tetrachlorvinphos 10.95 3.40 9.51 Tokuthion 11.35 7.36 14.57 15.59 Profenofos 11.43 6.38 8.13 8.92 9.65 12.27 16.2316.48 Ethion 12.27 9.30 11.43 16.66 Azinphos methyl (guthion) 14.57 7.39 10.85 5.59 16.71 L-Cyhalothrin 14.80 17.91 Pyrazophos 14.98 4.77 10.26 cis-Permethrin 15.59 9.72 trans-Permethrin 15.71 Cyfluthrin-1 16.12 0 3.50 4.50 5.50 6.50 7.50 8.50 9.50 10.50 11.50 12.50 13.50 14.50 15.50 16.50 17.50 18.50 19.50 Time Cyfluthrin-2 16.23 Cyfluthrin-3 16.28 Cyfluthrin-4 16.33 Cypermethrin-1 16.48 Organophosphorous Pesticides Cypermethrin-2 16.59 Synthetic Pyrethroids Cypermethrin-3 16.66 Cypermethrin-4 16.71 Fenvalerate-1 17.61 32 components – SIFI analysis in < 20min Fenvalerate-2 17.91 Deltamethrin 18.80 25
- 26. Pesticides in Food – AOAC 2007.1 On column Reporting Levels ng Methamidophos 0.02 Omethoate 0.04 Dimethoate 0.008 Dichloran 0.004 Tefluthrin 0.004 Azinphos methyl (guthion) 0.008 L-Cyhalothrin 0.016 Cis-Permethrin 0.04 Trans-Permethrin 0.02 Cyfluthrin-1 - 4 0.04 Cypermethrin-1 - 4 0.04 Fenvalerate 1-2 0.04 Deltamethrin 0.02 26
- 27. Analytical Results VOC by P&T GC/MS EPA 8260C 27
- 28. VOC by purge & trap GC/MS Standard US EPA Method 8260C • Extraction of solid waste samples (among others) • Analysis by purge & trap GC/MS • Tens to hundreds of target compounds Experiment Focus • Optimize EM setting for maximum dynamic range Method • Standard EPA 8260C methodology followed • Mega Mix with internal standards 28
- 29. VOC by purge & trap GC/MS – example chromatogram (40 g/mL) 73 74 Scan EI+ 100 55 TIC 3.13e8 64 71 53 68 59 76 56 57 78 83 % 52 47 81 31 51 84 43 42 45 22 37 23 34 35 48 14 18 9 10 29 36 41 44 79 7 16 17 50 19 26 32 6 11 49 3 39 1 15 2 5 4 40 80 0 Time 1.00 3.00 5.00 7.00 9.00 11.00 13.00 29
- 30. SVOC by GC/MS – Calibration Results (0.5-200 mg/L) Avg MDL Precision Accuracy # COMPOUND RRF %RSD (mg/L) %Rec %RSD 3 Vinyl Chloride 0.79 8.2 0.21 95 1.8 14 trans-1,2 Dichloroethene 0.46 9.3 0.34 105 1.3 31 Benzene 1.33 6.9 0.22 90 1.6 35 Trichloroethene 0.32 8.9 0.28 103 2.5 36 1,2-Dichloropropane 0.47 6 0.15 96 1.8 43 Toluene 0.67 6.5 0.22 100 1.5 48 1,3-Dichloropropane 0.65 4.4 0.06 94 3.1 50 Ethylene Dibromide 0.40 3.6 0.07 111 2.8 52 Chlorobenzene 1.08 4.7 0.23 102 1.0 54 1,1,1,2-Tetrachloroethane 0.27 7.8 0.19 105 1.9 63 1,1,2,2-Tetrachloroethane 1.17 5.9 0.16 93 9.9 74 1,3-Dichlorobenzene 1.64 9 0.22 98 0.7 83 Naphthalene 3.60 7.3 0.06 102 2.4 84 1,2,3-Trichlorobenzene 1.13 7.2 0.09 94 1.6 Average %RSD ~ 8% (all 80 compounds) 30
- 31. VOC by Purge & Trap – EIC reproducibility at MDL Scan EI+ 128 100 1.12e6 Extracted Ion of Naphthalene 0.5 g/L @ m/z = 128 %RSD = 3.8 % 0 Time 12.35 12.37 12.39 12.41 12.43 12.45 12.47 12.49 12.51 12.53 12.55 31
- 32. Conclusions • PerkinElmer Clarus SQ 8 GC/MS • SMARTsource for quick ion source change • EM Detector for enhanced sensitivity and flexibility • Analytical results • Test Standards • US EPA Method 8270D • AOAC 2007.1 Pesticide analysis • US EPA Method 8260C 32
- 33. Thank you and acknowledgement to the SQ 8 team 33
Editor's Notes
- (build)Line up the red dot, insert source until it stops, twist. Simple.Now it is possible to change sources in a matter of seconds. Either switch out dirty sources for clean ones Or switch out EI for CI and back againNow it is possible to change source components in a matter of minutes with no tools if a spare source is not available
- Video showing the removal of the source. Design is easy to twist and generates enough force to seal the vacuum chamber properly.
- (build)Function of components: Yoke receptacle – accepts, aligns, and makes electrical connection with SMARTsource. Guide pins – aligns the source correctly each time, every time. Quick Connect plug – provides filament, trap, repeller, and heater electrical connection. Connection automatically made upon inserting source. All of this is achieved just by twisting in the source
- REACH = European Community Regulation on chemicals and their safe use Registration, Evaluation, Authorisation and Restriction of Chemical substancesBasically, any company selling chemicals in the EU are required to demonstrate the purity and safety of their products. This data is from an SQ 8 Beta Tester Two spectra collected within 2 hours of each other – first the high pressure Positive CI data (top) followed by a cool down, vent, source swap, pump down and blank followed by the EI data (bottom). The Tester was extremely happy with the ease of switching between EI and CI. Compound – flame retardantBoth EI and CI data are required to positively identify the compound and demonstrate the lack of any contaminants. The top spectra was collected in high pressure PCI mode and would actually not be used for REACH. Typically CI results would indicate just the parent ion while this high pressure spectra shows substantial fragmentation.
- Same compound in support of REACHTop spectra is Positive CI – low pressure CI shows strong parent ion with only a few fragmentsMiddle spectra is EI – shows fragmentation patter that is library searchableBottom spectra is Negative CI – low pressure CI shows parent ion and only few fragments
- Switch to electron multiplier because of technological advancements.Enhanced sensitivity due to detector design and the noise reducing ability from removal of unwanted ions and neutrals.Operation flexibility is from the high sensitivity and the voltage range of the EM array (see slide 16)
- (build)A walk through of the detector design. Our supplier has patents for the geometry as well as for the advanced materials used in the conversion dynode. There are four fantastic design features of this detector: 1. The “Advanced Ion Optics” at the entrance of the detector filters random charged molecules that reach the detector. Using static focusing only molecules within a small ion trajectory range will traverse both the initial and secondary lenses. Other ions will either collide with the grounded entrance plate or one of the two lenses. 2. The 270 degree ion path filters neutrals that enter the detector by forcing the ions of interest to come off axis and wrap around before they enter the conversion dynode. The motion is not observed in the neutral molecules entering the detector which will simple hit the far wall of the detector. 3. The geometry and material of the conversion dynode is optimized for our system and protected by patents. Suffice to say that a maximum of electrons is generated for each ion impact at the dynode. 4. The electron multiplier amplifies the signal greater than any other discrete EM currently avaliable.
- (build)Shows the trajectory of ions and neutrals entering the detector up to the conversion dynodePause to allow neutrals (purple) to fly and hit the wall.The dynode is held at -10kV and over the lifetime of the detector assembly should not require cleaning as area is has low pressure and is in the “dar” area relative to detector opening. Any dirt that will build up will not deflect the -10kV with any authority.
- Simulation using Simion directly from OEM supplier.(build)A walk through of the detector design. Our supplier has patents for the geometry as well as for the advanced materials used in the conversion dynode. There are four fantastic design features of this detector: 1. The “Advanced Ion Optics” at the entrance of the detector filters random charged molecules that reach the detector. Using static focusing only molecules within a small ion trajectory range will traverse both the initial and secondary lenses. Other ions will either collide with the grounded entrance plate or one of the two lenses. 2. The 270 degree ion path filters neutrals that enter the detector by forcing the ions of interest to come off axis and wrap around before they enter the conversion dynode. The motion is not observed in the neutral molecules entering the detector which will simple hit the far wall of the detector. 3. The geometry and material of the conversion dynode is optimized for our system and protected by patents. Suffice to say that a maximum of electrons is generated for each ion impact at the dynode. 4. The electron multiplier amplifies the signal greater than any other discrete EM currently avaliable.
- The point of this slide is to explain how adjusting the EM voltage will allowing fine tuning of experiment parameters to meet the sensitivity requirements of a method. Data collected while monitoring m/z = 128, the quan ion of naphthalene, as the EM voltage was variedData points represent centroid intensity at m/z = 128UltraTune Custom (AutoTune) set the value at the apex indicated by the red mark This point represents a high sensitivity point If high sensitivity is a method requirement this would be a good place to start Additionally, the EM voltage could be increased if this value was found to be insufficientThe red bar at the bottom is the entire range where naphthalene is detectable As the EM voltage is lowered the upper concentration of naphthalene detectable, and therefor dynamic range, is increasedAlso – the voltage required for standard operation of the EM will increase as the hardware “breaks-in”. Throughout most of the lifetime the EM will function at a plateau until it begins to die at which point it will require higher and higher EM voltage to function correctly.IMPORTANT – using the EM at substantially higher voltages than what AutoTune sets will shorten the lifetime of the detector.
- OFN is a test standard that is generally used to spec out single quad instruments sensitivity. It is not an ASTM method but is simply generally used. We, as many other manufacturers (but not all), use 1pg/uL with a 1 uL injection 1pg OFNSpecs for the SQ 8 are: T&C 800:1 EI 1200:1 PCI 10,000:1 NCI S 650:1 EI
- Three sequential OFN measurements on a T model. All three are well above the 800:1 specVariation in values, 1200, 1200, 1500, are due to the variability of the noise. Numbers are S/N, NOT area…
- Summary of US EPA Method 8270D common environmental application looking at SVOA compounds liquid injection, typically pressure pulse Can be up to 300 compounds analyzed per sampleFocus of this work, which was presented as application note, was a wide dynamic rangeImage shows cover of resulting app note
- Nice chromatography of the 72 compounds analyzed
- Method requires use of relative response factors (RRF) for calibrationRT = retention time of peak# matches previous labeled chromatogramSatisfaction of EPA method criteria Good individual RRF values and statistics Good overall RRF
- This is work as proof of concept, not complete applicationAOAC 2007.1 method specifies the four fruits/veggies listed but can be applied to any other fruit/veggie IF sufficient criteria are metThis is a SIFI method which combines single ion monitoring with full scan dataThe success thus far is good chromatography and 24 of the 32 listed pesticides passing specifictaions
- List of all components and sample chromatogram. Chromatogram is second highest cal point at 2 ug/mL typyical, but a range of 0.04 – 4.0 ug/mL. Calibration standard comes with non uniform, adjusted concentrations so a range between compounds is typical.
- Observed on column reporting levels
- Summary of US EPA Method 8260C common environmental application looking at VOC compounds purge and trap sample introudction, done with Tekmar Atomx Can be up to 300 compounds analyzed per sampleFocus of this work, which was presented as application note, was a wide dynamic rangeImage shows cover of resulting app note
- Nice chromatography of the 84 compounds analyzed
- Method requires use of relative response factors (RRF) for calibrationRT = retention time of peak# matches previous labeled chromatogramSatisfaction of EPA method criteria Good individual RRF values and statistics Good overall RRF MDL done at 0.5 ug/L Precision & Accuracy done at 25 ug/L
- Extracted ion chromatogram of MDL (0.5 ug/L) naphthalene samples at m/z = 128%RSD fantastic for low level sample
- The Blizzard/SQ 8 team in Shelton, CT, USA.From left to right:Frank DeLorenzo – SQA TestingDamon – ManufacturingCharles Mangarella – ConsumablesLeon Mandrona – EngineeringRicardo Ponce de Leon – ManufacturingWilliam Goodman – PPRDPaul – ManufacturingRuben Garnica – PPRDSheila Eletto – MarketingJason Ashe – ConsumablesDawn May – SQA TestingYury Kaplan – SQA TestingRoss Mannino – EngineeringJamie Sauser – EngineeringPaul Schallis – EngineeringAdam Patkin – PPRDGreg Hanlon – EngineeringAndrew Tipler – PPRDRobert Bielecki – DocumentationKeith Ferreira – EngineeringHenry Gobi – EngineeringDavid Catherman – Service