Characterization and Reproducibility of Vapochromic Sensors

Transcription

1 Characterization and Reproducibility of Vapochromic Sensors Charles W. Branham, Brian Marquardt Applied Physics Laboratory - University of Washington Conor Smith, Kari McGee, Kyle Schwartz, Kent Mann University of Minnesota

2 Vapochromic Oxygen Sensor with High Oxygen Permeability and Large Void Space Aaxisview Oxygen sensor! PtPDT Bulky ligands and cations create large void space in crystal lattice Oxygen selective fluorine substituents increase the oxygen affinity/permeability of the sensor Greatly improves the response time and stability of sensor Sensor s crystal structure has 2% void space, green atoms are fluorine substituents

3 Oxygen Sensor Applications Applications 1. Monitor Biological Processes (Fermentors, Proteomics) 2. Monitor Industrial Processes (Reaction Vessels, Corrosion) 3. Monitor Ocean Processes (Argo floats, SeaGliders, Moorings) 4. Environmental Monitoring (Air Quality: submarines, space shuttle, airplanes, industrial work areas, )

4 Design of Oxygen Fiber Optic Sensor Automated Circor NeSSI Gas/Vapor System Sensor Tip Vapochromic Fiber Optic Oxygen Sensor Various mixtures of dry nitrogen and air were used to calibrate Oxygen Fiber Optic Sensor

5 PLS of Dissolved O 2 Sensor Response 5 replicates at each concentration Concentration range: 1 μmol/l 55 μmol/l 1 μmol/l 55 μmol/l 1 μmol/l = 32.5 ppb

6 Solution Response Time Experimental Setup The response time of the oxygen sensor was determined by allowing it to come to equilibrium with one gas saturated water sample and then quickly flushed with a different gas saturated water sample. Spectral data were taken every second during these experiments. Gas Saturated DI Water Reservoirs (500mL) Flow Cell Valves Waste DO Probe

7 Determination of Purge Rate of Flow Cell 1.6 Absorption Dye was placed in the flow cell and then was exchanged with pure water Plot of dye Absorption at 495 nm sec Time(ms) It took approximately 1.5 sec to exchange the full volume

8 Response Time of Oxygen Sensor to Air-to- Oxygen/Nitrogen Saturated Water Nitrogen 100% 8sec 95% 5sec 3 Replicates Averaged Air 100% 6sec 95% 2sec 3 replicates Averaged Oxygen Compound/ polymer PtDPT/Teflon Most other Oxygen Sensors Mean Response Time of Exchanges between O 2, N 2, Air (T 95% ) 3.7 s 30 s Loloee. R., et al., IEEE Sensors, 2007, 1404.

9 Evaluation of Oxygen Sensor in Seawater A oxygen sensor and a commercial optical oxygen sensor were place in a temperature controlled flask with 40ppth seawater. The flask was bubbled with air and held at 30 C for 36 hours. Our DO Sensor Commercial DO Sensor Temperature Controlled Flask

10 Response of Commercial Optical DO Sensor in Air Saturated Seawater Water for 36 hour at 30 C The sensor began to salt up after 18 hours, rendering it useless as a reference. Calcium carbonate build up?

11 Effects of Conductivity/Salinity and Temperature on the Oxygen Sensor An oxygen sensor and a conductivity probe were placed in a temperature controlled flask. Three temperatures(11, 20 and 29 C) and four seawater concentrations[0(0ppth), 30(13ppth), 60(26ppth) and 100%(40ppth)] were evaluated. The flask was bubbled at each oxygen concentration for 40 min at each temperature then five spectra were taken. S = Salinity, C = Conductivity DO = Dissolved Oxygen, A# and B# correction coefficient, T = Temperature

12 Predicted Oxygen Concentration(micromol/liter) PLS Model of Oxygen Sensor Response to T and Measured Salinity R 2 = Latent Variables RMSEC = Bias = e : 0% Seawater, 11.2 Celsius 2: 30% Seawater, 11.2 Celsius 3: 60% Seawater, 10.8 Celsius 4: 100% Seawater, 11.2 Celsius 5: 0% Seawater, 20.0 Celsius 6: 30% Seawater, 20.0 Celsius 7: 60% Seawater, 19.9 Celsius 8: 100% Seawater, 20.0 Celsius 9: 0% Seawater, 29.3 Celsius 10: 30% Seawater, 29.3 Celsius 11: 60% Seawater, 29.2 Celsius 12:100% Seawater, 29.3 Celsius Measured Oxygen Concentration(micromol/liter)

13 Conclusion Commercial oxygen sensor fouled after 18 hours, our sensor remained unfouled for the whole 36 hours Calculating the oxygen concentration from salinity and temperature gave good results, however an oxygen reference would have been better The PLS model of the our oxygen sensor validated by the calculated oxygen concentrations was surprisingly accurate In the future this experiment will be repeated once we obtain a more robust oxygen reference

14 Evaluation of Multiple Oxygen Sensors Simultaneously Mixed Gas Oxygen Reference Liquid Reservoir Spectrometer Light Source Liquid Flow Direction Pump Multiplexer Optical Signal Temperature Controlled Flask 8-port Temperature Controlled Sensor Block (7 Sensors Measured Simultaneously)

15 Custom GUI for Multi-Sensor Apparatus

16 Multiple Sensor Evaluation Results 7 Oxygen sensors were held at 23 C; 0, 25, 50 and 100% oxygen saturated water was evaluated. The response of the oxygen sensor to each concentration was used to build a PLS model and validated with the oxygen reference. Predicted Oxygen Concentration(micromol/liter) Sensor R 2 RMSEC Mean ±std ± ±10.67 Resulting PLS model from sensor 0003 R 2 = Latent Variables RMSEC = Bias = e Measured Oxygen Concentration(micromol/liter)

17 Conclusions The first data set obtained from this apparatus yielded extremely reproducible results from 7 sensors, avg R ±0.005 Work will continue to optimize and develop this apparatus for statistical analysis of multiple sensors. We plan to evaluate and compare sensors produced under a variety of conditions Batch-to-batch comparisons Sensor tip comparisons Sensor membrane thickness comparisons Historical and newly developed oxygen sensor chemistry comparisons

18 New Oxygen and Carbon Dioxide Sensors Inexpensive copper complexes for oxygen detection and measurement First carbon dioxide sensor to exhibit a fluorescence shift

19 Long-Lived Cu(phen) 2 + Excited States that can be Quenched by O 2 Pseudotetrahedral [Cu(phen) 2 ] + Emission spectra excited at 400 nm for [Cu(dipp) 2 ]tfpb. The spectra under pure nitrogen and pure oxygen are shown in blue and red, respectively. Mole fraction of O 2 in N 2 from top to bottom is 0, 0.193, 0.379, 0.659, 1.

20 X-ray Structure of [Cu(phen derivatives) 2 ] tfpb Contain Channels [Cu(2,9-dimethylphenanthroline) 2 tfpb] Calculated void space as red space filling spheres for [Cu(dipp) 2 ]tfpb (fluorine atoms shown as green space filling spheres.

21 Stern-Volmer Plots for Three Cu(I) Complexes Stern-Volmer plots for typical samples of [Cu(dipp) 2 ]BF 4 (green), [Cu(dmp)(dbp)]tfpb (blue) and [Cu(dipp) 2 ]tfpb (red). K sv values of 0.103(4), 0.155(4)and 0.299(7), respectively.

22 Movie Time!

23 Relevance of CO 2 Detection Environmental analysis water and air quality Clinical Setting breath and blood Industrial cracking down on emissions Classic methods of CO 2 detection need improvement expensive slow non-portable

24 Feasibility of CO 2 Detection CO 2 is considered to be inert a tough nut to crack not a collisional quencher Physical methods IR absorption spectroscopy (2349, 1388 cm -1 ) Chemical methods (actually measure ph not CO 2 ) Electrochemical Optical Based on:

25 The Goal: Direct Detection of CO 2 Would allow for dramatically simpler sensing by eliminating: dependence on CO 2 hydration kinetics use of buffers and enzymes the need for multiple fluorophores CO 2 chemistry is needed to accomplish such a goal reversible fast Carbamate equilibrium Hydrazine Carbazic acid

26 First Example of Direct CO 2 detection by a Fluorescence Shift Bis hydrazine complex rapidly converts to carbazate at room temperature More to Come in 09 and 10!

27 Vapochromic Project Publications Supported by CPAC 158. Pairing of Old Chemistry With a Luminescent Ir(III) Complex for the Optical Detection of Carbon Dioxide. Kyle Schwartz and Kent R. Mann, manuscript in preparation Void-Space Containing Crystalline Cu(I) Phenanthroline Complexes As Molecular Oxygen Sensors Conor S. Smith and Kent R. Mann, submitted to Chemistry of Materials Inefficient crystal packing in chiral [Ru(phen) 3 ](PF 6 ) 2 enables oxygen molecule quenching of the solid-state MLCT emission. McGee, Kari A.; Mann, Kent R. Journal of the American Chemical Society (2009), 131(5), Concurrent sensing of benzene and oxygen by a crystalline salt of tris(5,6-dimethyl-1,10- phenanthroline)ruthenium(ii). McGee, Kari A.; Marquardt, Brian J.; Mann, Kent R. Inorganic Chemistry (2008), 47(20), Porous Crystalline Ruthenium Complexes Are Oxygen Sensors. McGee, Kari A.; Veltkamp, David J.; Marquardt, Brian J.; Mann, Kent R. Journal of the American Chemical Society (2007), 129(49), A Comparison of Isomers: trans- and cis-dicyanobis(para-ethylisocyanobenzene) Platinum. Dylla, Anthony G.; Janzen, Daron E.; Pomije, Marie K.; Mann, Kent R. Organometallics (2007), 26(25), Selective Low-Temperature Syntheses of Facial and Meridional Tris-cyclometalated Iridium(III) Complexes. McGee, Kari A.; Mann, Kent R. Inorganic Chemistry (2007), 46(19), A Humidity Sensor Based on Vapoluminescent Platinum(II) Double Salt. Materials Steven M. Drew, Jennifer E. Mann, Brian J. Marquardt, Kent R. Mann, Sensors and Actuators (B) (2004), 97(2-3), Characterization of a Cross-Reactive Electronic Nose with Vapoluminescent Array Elements. Steven M. Drew, Daron E. Janzen, Kent R. Mann. Analytical Chemistry (2002), 74(11), Steplike Response Behavior of a New Vapochromic Platinum Complex Observed with Simultaneous Acoustic Wave Sensor and Optical Reflectance Measurements. Jay W. Grate, Leslie K. Moore, Daron E. Janzen, David J. Veltkamp, Steve Kaganove, Steven M. Drew and Kent R. Mann. Chemistry of Materials; 2002; 14(3); An Electronic Nose Transducer Array of Vapoluminescent Platinum(II) Double Salts. A Convenient Synthesis of Tris-heteroleptic Ruthenium(II) Polypyridyl Complexes. Steven M. Drew, Daron E. Janzen, Carrie E. Buss, Daniel I. MacEwan, Kimberly M. Dublin, Kent R. Mann J. Am. Chem. Soc., 123, 8414 (2001) Structural Investigations of Vapochromic Behavior. X-Ray Single-Crystal and Powder Diffraction Studies of [Pt(CN-iso-C 3 H 7 ) 4 ][M(CN) 4 ] M = Pt or Pd. Carrie E. Buss, Carolyn E. Anderson, Marie K. Pomije, Christopher M. Lutz, Doyle Britton and Kent R. Mann J. Am. Chem. Soc., 120, 7783 (1998).

28 Acknowledgements University of Washington: Wes Thompson, Brian Marquardt, Bart Kahr University of Minnesota: Kari McGee, Conor Smith, Kyle Schwartz, Kent Mann Center for Process Analytical Chemistry (CPAC) ExxonMobil Tetracore Inc. Applied Physics Libratory (APL) Initiative for Renewable Energy and the Environment (IREE) Materials Research Science and Engineering Center (MRSEC)