Performance Characterization and Field Testing of a Portable Tandem Mass Spectrometer John Grossenbacher Mitch Wells, Garth Patterson, Brent Knecht, Dennis Barket, Jr., Brent Rardin, Mark Gregory, Jason Springston, Rob Donoho Griffin Analytical Technologies Inc. West Lafayette, IN www.griffinanalytical.com
Griffin Analytical Technologies Technology transfer from Purdue s top-tier Analytical Chemistry Department Exclusive license in all fields of use Developing miniaturized, portable mass spectrometer-based instrumentation that provides bench-top performance in a portable package Chemistry Happens Outside the Lab So Should Analysis.
Field MS Applications Homeland Security/Defense Detection surrounding potential terrorist targets Transportation security Forward-deployed protection of troops On-site Environmental Monitoring Water quality Continuous air monitor R&D Tool for Chemical Warfare Testing
Advantages of the Cylindrical Ion Trap Operation under relatively high vacuum ~10-4 Torr MS/MS capabilities Selectivity Ease of machining/manufacturing Reduced voltage requirements
Ion Trap Comparison Standard Ion Trap Cylindrical Ion Trap electrodes mass resolution MS n capability Hyperbolic radius = 10 mm req d. voltage ~8000 V (at 1.1 MHz) mass range 1000 amu (typical) unit (typical) MS 4 (typical) Flat radius = 2.5 mm ~600 V (at 1.1 MHz) 350 amu (typical) unit (demonstrated) MS 3 (demonstrated) Result of Difference Simplified machining, lower operating voltage Smaller electronics, lower power consumption Range for target applications Performance comparable Performance comparable
Minotaur Instrument Minotaur Specifications: Mass Analyzer: Cylindrical Ion Trap Sample Inlet: Internal Membrane Ionization: Internal Electron Ionization (EI) MS3: Demonstrated Sensitivity: LODs of ppb to pptr, compound specific Mass Range: 350 Da/charge Resolution: ~unit Bath Gas: ambient air (~10-4 Torr) Detection: positive and negative ions Size: 60 cm x 45 cm x 20 cm (~1.9 cu. Ft.) Weight: under 50 lbs. (with case and pumps) Power Consumption: ~100 W
Griffin Analytical Technologies Instrument Control Software Scan Editor - development software Advanced Waveform Editing Data Collection
Griffin Analytical Technologies Instrument Control Software Data Analysis
Griffin Analytical Technologies Inlets and Sources Currently In Use MIMS Silastic PDMS tubular membrane (0.64 mm i.d., 1.19 mm o.d.), ~2 cm long Sampling flow rate 0.5 L/min Onboard sampling pump Internal EI In Development SPME inlet GC interface Other interfaces are under development including external ionization sources
Gas-phase Standards Dynamic VOC Standards Standard compound Dilution air Mass flow controller 4.10 dump Mass flow controller 41.0 Mixing coil to MMS tee
Gas-phase Standards Bag Standards Mass flow controller 10.0 Syringe containing standard solution 3 mil PFA Teflon bag Heated Glass tee 150 L Dilution Air
Sampling Protocol Continuous sampling with MIMS (toluene) 2. Pervaporation 1. Sample Membrane Trap and Release MIMS (Methyl Salicylate, Triethyl Phosphate (TEP), Dimethyl Methylphosphonate (DMMP) 1. Sample Membrane 2. Trap 3. Release Sorbent Trapping with Tenax (Methyl Salicylate) 1. Sample 2. Heat/Desorb 3. Trap 4. Release Tenax tube Membrane
Minotaur Performance: Real-time Monitoring of VOCs Toluene LOD = 15 ppb 91/92 peak area 20 12 4 0 y 19.329x y R= 2 0.9514 19.3x R 2 = 0.946 0.4 0.8 1.2 Concentration (ppm) Abundance (arb. units) 100 91 50 92 65 60 70 80 90 100 m/z
Minotaur Performance: Trap-and-Release of Semi-Volatiles Methyl Salicylate LOD = 300 pptr m/z 92, 120, 152 peak areas 2.5E5 1.5E5 5E4 Abundance (arb. units) 50 40 30 20 10 92 120 70 90 110 130 150 m/z 8 ppb standard 152 y = 221.8x R 2 = 0.998 0 200 400 600 800 1000 Concentration (ppb) 1200
Minotaur Performance: Field Testing Methyl Salicylate with Sorption Tube Sampling m/z 92, 120, 152 peak areas 2.0E5 1.2E5 4E4 y = 65.1x R 2 = 0.998 LOD = 77 ppb 0 500 1000 1500 2000 2500 3000 Concentration (ppb)
Minotaur Performance: Trap-and-Release of triethyl phosphate (TEP) 283 ppb standard LOD 150 ppb TIC (arbitrary units) 5E4 3E4 1E4 signal (arbitrary units) 1.6E5 1.2E5 8E4 4E4 y = 166.9x - 25000 R 2 = 0.994 0 0 5 10 15 20 25 30 time (minutes) 0 200 400 600 800 1000 concentration (ppb)
Under Development: External Ionization Atmospheric Sampling Glow Discharge Ionization (ASGDI) explosives detection CW agents high voltage sample in ions to CIT Abundance (arb. units) PDCH 900 700 500 300 C 3 F - 7 C 4 F - 100 7 150 200 ~0.5 Torr (M-C 2 F 5 ) - (M-CF 3 ) - 250 300 350 m/z
Challenges with Current Technology Analyzer Vacuum Requirements Traps Quads Sectors E TOF D B ICR 10-3 10-4 10-5 10-6 10-7 10-8 10-9 pressure (Torr)
Challenges with Current Technology Vacuum Pumping power consumer, delicate
Challenges with Current Technology Miniaturization of High Voltage Electronics Size limited by HV line separation and component spacing Relatively high quiescent power consumption Broadcast/Electromagnetic Interference (EMI)
Future Directions Develop innovative sample introduction/ionization techniques Tailored to specific applications Increased selectivity Funding secured Refinement of instrument package Volume: ~1.5 cu. ft. Weight: ~40 lbs Further Ruggedization for field use
Acknowledgements U.S. EPA, NSF, and DoD for funding Prof. R.G. Cooks The Griffin Team