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Oxytetracycline at Environmental Interfaces Studied by Second Harmonic Generation. Patrick L. Hayes and Franz M. Geiger Department of Chemistry, Northwestern University, Evanston IL WMRC Symposium on PPCPs in the Illinois Environment -- April 25, 2008. Oxytetracycline.

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slide1

Oxytetracycline at Environmental Interfaces Studied

by Second Harmonic Generation

Patrick L. Hayes and Franz M. Geiger

Department of Chemistry, Northwestern University, Evanston IL

WMRC Symposium on PPCPs in the Illinois Environment -- April 25, 2008

slide2

Oxytetracycline

Oxytetracycline (OTC)

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

Morantel

Konek et al. J. Am. Chem. Soc. 2005,127, 15771.

slide3

Oxytetracycline

Oxytetracycline (OTC)

  • Tetracyclines are used in humans and cattle/poultry/swine
  • Estimated 3 million pounds of tetracyclines used annually for growth stimulation in livestock!
  • 25-75% of tetracyclines administered to animals are excreted in the active form.

Hileman, B. “Resistance is on the Rise” Chem. Eng. News 2001,February 19, 47.

Kulshrestha, P.; Giese, R. F. Aga, D.S. Environ. Sci. Technol. 2004, 38, 4097.

Boxall, A. B. A. EMBO Reports 2004,5, 1110.

Simon, N. S. Environ. Sci. Technol. 2005,39, 3480.

slide4

Importance of Mobility: Case I “A Sticky Antibiotic”

Bacterium

Bacterium

Bacterium

Resistant

Sticky

Antibiotic

SoilParticle

SoilParticle

SoilParticle

SoilParticle

Antibiotic Resistance in Soil Bacteria

Localized

slide5

Resistant

Resistant

Resistant

Resistant

SoilParticle

SoilParticle

SoilParticle

SoilParticle

Antibiotic Resistance in Soil Bacteria

Importance of Mobility: Case II “A Mobile Antibiotic”

Mobile

Antibiotic

Koike et al. Appl. Envir. Microbiol. 2007, 73, 4813.

slide6

Challenges:

  • Complexity
  • Separating Bulk from Surface
  • Sensitivity

Soils

Pollutant Plume

Water Table

Second Harmonic Generation

Surface

Waters

Environmental Interfaces Control Transport,Reactivity, Bioavailability

slide7

Water

Second

Harmonic

Generation

(SHG)

Aqueous

UV-Vis Spectrum

Fundamental

Laser Light

Nitrate Surface Spectrum

Quartz

Fused Quartz/Water

Surface Spectrum

Second Harmonic Generation (SHG)

  • Advantages:
  • Surface-Specific
  • Sensitivity Allows for Real-time
    • Monitoring of Adsorption
  • Experiments Run Under Flow Conditions

“Measurable” is ESHG  Nads

Eisenthal, K. B. Chem. Rev. 1996, 96, 1343.

Shen, Y. R. “The Principles of Nonlinear Optics” John Wiley & Sons: New York, 2003.

slide8

I

I

time

time

SiO2

laser

PMT

Aqueous Phase

Waste

Teflon Flow Cell

Analyte

Water

UV-Vis

Experimental Setup

Pulsed & Tunable Laser

Mifflin, A.L.; Gerth, K.A.; Weiss, B.M. Geiger, F.M. J. Phys. Chem. A 2003, 107, 6212.

Mifflin, A.L.; Gerth, K.A.; Geiger, F.M. J. Phys. Chem. A2003, 107, 9620.

Mifflin, A.L.; Musorrafiti, M.J.; Konek, C.T.; Geiger, F.M. J. Phys. Chem.B2005,109, 24386.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

slide9

Model Environmental Interfaces

Fused Quartz

Pollutant

Common Organic Motifs

Organic Adlayer

SoilParticle

Increasing Complexity

Our Strategy:

Use synthetic chemistry to:

Isolate and study individual functional groups.

Build more complex model interfaces.

Sutton, R.; Sposito, G. Environ. Sci. Technol. 2005, 39, 9009.

Al-Abadleh et al. J. Am. Chem. Soc. 2004,126, 11126.

Gibbs-Davis, J.M.; Hayes, P.L.; Scheidt K. A.; Geiger F.M. J. Am. Chem. Soc. 2007, 129, 7175.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

slide10

OTC Spectroscopy and Adsorption/Desorption TraceatFused Quartz/Water Interface(pH 8)

OTC

UV-Vis

SHG OTC

Fused Quartz/Water

OTC

5 x 10–5 M

H2O

H2O

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

slide11

R =1+(r/n).Kd

C/Co

Pollutant

Water

x

0

OTC Isotherm & The Kd Model (pH 8)

Retardation Factor:

Kd = 0.11 mL/g

Taking: (/n) = 4 – 10 g/cm3

Rf = 1.44 - 2.1

Rf = 2, corresponds to 50%

reduction in OTC mobility relative

to water.

Langmuir, D. Aqueous Environmental Geochemistry; Prentice Hall,Inc: New Jersey, 1997.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

slide12

Summary of Isotherm Experiments: Mobility

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

slide13

Predicting OTC Mobility: Surface Energy and OTC Retardation

For Hydrogen-Bonding

Surfaces, and Taking:

(/n) = 4 -10 g/cm3

(c)

 = 49º, 9 mJ/m2

f

e

(f)

c

 = 75º, 22 mJ/m2

d

a

b

(a)

(b)

(c)

(d)

(e)

(f)

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

slide14

Predicting OTC Mobility: Surface Energy and OTC Retardation

For Hydrogen-Bonding

Surfaces, and Taking:

(/n) = 4 -10 g/cm3

IHSS Humic Acid:

f

Contact Angle: 59(3)

Surface Energy: 14(1) mJ/m2

Predicted Rf: 1.4(1)

e

c

IHSS HA

Aldrich Humic Acid:

d

Aldrich HA

Contact Angle: 57(3)

Surface Energy: 13(1) mJ/m2

Predicted Rf: 1.3(1)

a

b

(a)

(b)

(c)

(d)

(e)

(f)

Mifflin et al. J. Phys. Chem. B 2006, 110, 22577.

Hayes et al. J. Phys. Chem. C 2007, 111, 8796.

slide15

f

e

c

d

a

b

Mobile

OTC ???

Connections to Mobility

  • OTC will tend to be less mobile in silica-rich soils that:
  • Contain natural organic matter with a large density of benzoic acid functional groups
  • Display high interfacial energy
slide16

Geiger Group 2006

Acknowledgements

  • Professor Franz M. Geiger
  • Dr. Amanda Mifflin (OTC)
  • Dr. Julianne Gibbs-Davis
  • Professor Karl A. Scheidt

Funding: