Utilizing NeSSI™ for Analytical Applications

1. Utilizing NeSSI™ for Analytical Applications Dave Veltkamp* Brian Marquardt* Charlie Branham† *Center for Process Analytical Chemistry (CPAC) University of Washington, Seattle WA † Grad Student from Bart Kahr’s group in Chemistry, UW

2. CPAC Project Overview • Goal is to support NeSSI related development within CPAC • Developing platforms and demo applications • Support PI and student use in research programs • Promote and support wider NeSSI adoption and use • Web based support • Interaction with NeSSI community • Legal umbrella for cooperative development

3. NeSSI substrate with 3 MFC’s • 2 bubblers for vapor generation 1 MFC Controls N2 dilution flow Single inlet line (N2) Outlet lineto flow cell Standard Ace Glass impingers 2 MFCs Control N2 flow to bubblers Old NeSSI Gas/Vapor System

4. Optical Flow Cell • Flow cell is a simple cross fitting • 6-around-1 fiber optic for source and collection • Delrin rod with sensing compound coated on end • Multiple crosses can be chained together for screening several compounds at once • Optical detection using simple reflectance optical measurement • Ocean Optics USB2000 VIS spectrometer (350-1000 nm) • 405 nm blue LED excitation • Compound fluorescence signal in region 600-900 nm

5. Vapochromatic Response Full spectrum response of the 0%, 10%, and 50% bubbler flow samples used to make the PLS model showing both the change in intensity and shift in peak maximum with changing benzene concentration.

6. Vapochromic #1 Response * MFC #3 run at 5% FF rather than 50% FF

7. Vapochromic #3 Response

8. Bubbler Results (Benzene Conc.) Benzene concentration (ppm) calculated from the weight loss experiment data as a function of bubbler flow rate (%FF N2)

9. New Gas Sensor Testing System • More capability to generate analytical vapors, gas blending, and on-line dilution of vapor streams for method development work • This system delivered by CORCOR Tech to UM last week and will facilitate collaboration with Kent Mann

10. The New CIRCOR NeSSI System Has Arrived in Minnesota

11. Reconfiguration of CPAC NeSSI™ System • Our Swagelok NeSSI™ system proven to be very easy to change to suit needs • Replaced bubblers with permeation tubes and oven • Changed to look at CO2 in N2 blending • Changed to look at O2 and moisture in air • Investigation of flow, mixing, and dead volumes • Used to evaluated new analytical instruments in CPAC lab • ASI microFast GC – 2 column GC with trap injection • Aspectrics EP-IR mid infrared spectrometer with gas cell • LabVIEW software developed to automate experiments

12. Reconfigured NeSSI™ System

13. Schematic of System • Needed to design system with multiple (3) dilution stages • Somewhat complex flow paths to minimize dead volumes • Had to compromise automated vs. manual control of N2 flows in first two stages • Lack of additional MFCs required manual metering valves

14. System Flows • By closing valves and using the MFCs as flow meters, all flows can be measured • Closing off the N2 flows (SV2 and MFC2) and waste valves (PV3 and PV4) allows flow thru bubbler to be measured • MFC3 and MFC1 set to “valve open” setpoint • All flow streams and legs of system can be flushed by N2

15. System Flows (cont.)

16. Dilution Flows • 1st dilution of bubbler flow at input to MFC 3 • Most of flow goes to waste, MFC setpoint typically 1-5% • N2 flow regulated by waste needle valve • 2nd dilution at outlet port of MFC 3 • Again most of flow going to waste, MFC 1 set to 1-5% • N2 and 2nd diluted sample flows set by needle valves PV2 and PV4 • 3rd dilution at output port of MFC 1 • N2 flow controlled by MFC 2 • Important to balance pressures and flows to avoid unexpected flow conditions – some tweaking required!!

17. Aspectrics EP-IR Instrument • 128 channels from 2.50 to 5.00 microns (4000-2000 cm-1) • Each channel approx 19.7 nm wide “band pass” • Also a 256 channel model available • Runs at an acquisition frequency of 100 scans (rotation) per second • Real-time data collection of fast events • High averaging for low LOD applications • Small size and rugged construction • Only moving part is the encoder disk • Suitable for high vibration process environments • No hygroscopic parts • Several optical configuration of sampling cell/accessories possible • Powerful on-line embedded chemometrics software

18. Aspectrics EP-IR Technology

19. Aspectrics EP-IR with Gas Cell 15” 7” Spectrometer 5.2” Gas cell Glow source

20. ASI microFAST GC™ • System on loan from ASI as part of WTC project with Infometrix • Programmed temperature gas chromatograph using • Syringe or valve inlets to a flash evaporator. • Sample delivery to an adsorbent trap for concentration • Desorbtion and delivery to twin capillary columns • Temperature programmed column elution • Detection by simultaneous flame ionization detectors (FID). • Trace levels down to low parts per billion can be measured. • Compact and easy to setup chromatography • Weight on the order of 12 pounds • Size on the order of a shoe box • Speed of analysis on the order of 10 times faster than competitors • Very easy to use • Trap injection makes it simple to use and automate • Really more like a spectrometer or sensor in operation • Even non-chromatographers can use it!!

21. dual columns and heater assembly column Fan compartment sheath end of finger heated head of tight columns columns connections zone Injector Heater FID Manifold Back Panel splitter septa flow restrictor Heated FID Air Sample Inlet carrier FID Vents flow removable glass liner V4(n open) Injection Trap & FID external Heater cooling fuel purge fan hydrogen V2 V8 V1 V5 V3 @ 40psi P P P Ballast electronic pressure regulators Pneumatic Manifold Injector vent Restrictor Vacumn Pump vent vacuum pump vent ASI microFAST GC™

22. Columntemperaturesensor column #1100 micron IDDB-5 Columnsoven sheath~1mm ID column #2100 micron IDDB-1701 Columnheater column heater sheath microFAST GC™ Column Details 3 meter column length

23. microFAST GC™ Analytical Cycle Typically 2-3 minutes Sample Time Trap pre-purge time Column cool-down time Equilibrate time Injection time Trap cool-down time Trap preheat time Trap cleanout time Column separation time Adjustable parameters that affect analysis – lots of tuning potential

24. Interfacing to ASI microFast GC™

25. Example Benzene Chromatograms Not very demanding chromatography – but convenient reference method

26. Experiment: Blending CO2 with N2 • Goal was to characterize the NeSSI™ system, software control, and the EP-IR gas cell data collection • Series of step changes in MFC setpoints for CO2 dilution • Different hold times (delay) between setpoint changes • Series repeated 5½ times • Bubbler replaced with CO2 from tank • Results show very good reproducibility and control of the gas blending system • Dynamic response consistent with expectations • No dead volume issues

27. CO2 Blending Experimental Design Note: MFC #2 offset by 90%FF, numbers on plot represent step hold time

28. EP-IR Spectra from CO2 Experiment

29. 1st PC of EP-IR Spectra PCA Model

30. Step times and Spectral Response CO2 setpoints inverted & offset for clarity Note: Total flow = 250 sccm, volume of cell ~ 210 ml – so about 1-2 min exchange time (lag) seems about right

31. CO2 Exp. Cycle Reproducibility

32. 2nd PC of EP-IR Spectra PCA Model

33. PCA results showing nonlinear behavior at high CO2 conc.

34. On-line Chemometric Model Results

35. dilution flow NeSSI™ Permeation Tubes • Used a stainless steel condenser as “oven” for permeation tubes • Removed condenser core and replaced with permeation tubes • Mounted in single-port ½” adapter to direct N2 up thru oven • Second ¼” adapter block returns flow into NeSSI™ • Temperature maintained by flowing water thru jacket from heater/chiller • Permeation tubes made in-house • Teflon tubing sealed at both ends • Made different tubes for water, benzene, and toluene vapors

36. Permeation Tube Results • Water permeation tube study • Vapochrome compound (Kafty) • Oven temp. set at 50°C • MFC flow rate set at 10%, 20%, 30%, 40%, and 50% for 30 min • Spectra taken at each flow rate • Benzene permeation tube • Vapochrome compound (#4) • Oven temp. set at 30°C • MFC flow rate set at 0%, 10%, 20%, 30%, 40%, and 50% for 30 min • Spectra taken at each flow rate

37. Conclusions and Future Work • Setup of NeSSI™ Vapor Platform complete (for now) • LabVIEW software developed and tested • Flow dynamics tested and characterized • New vapor generation ideas to be tested • New instrumentation interfaced and tested • Both Aspectrics EP-IR and ASI microFAST GC™ valuable additional tools for monitoring gas mixing and delivery • Additional applications from Sponsors welcome • Vapochromic compound testing continuing • Moisture, CO2, O2 and BTEX sensors testing underway • Additional screening and analytical performance testing planned • Plan to get back to some microreactor work • Parker NeSSI™ system for reactant and product streams • Microreactor components from Microglass & IMM on hand • Fuel cell studies with Eric Stuve and Chem. E. students planned • WTC Project with Infometrix on Process GC interfaced to NeSSI™