1. Prashanth Upadhya, Yao-Chun Shen, Giles Davies & Edmund Linfield Terahertz Time-Domain Spectroscopy of Glucose and Uric Acid Cavendish Laboratory, Cambridge University

2. IntroductionExperiment Far-infrared absorption  Glucose and sucrose  Glucose and sucrose  Uric Acid & its derivative  Uric Acid & its derivative Temperature & structural dependent absorption Conclusions Contents

3. Introduction many intrinsic resonances predicted in the THz regime  vibrational modes in polynucleotides  vibrational modes in polynucleotides … Powell et al … Powell et al  base twisting and librational modes in DNA structure  base twisting and librational modes in DNA structure … Young et al … Young et al low frequency collective vibrational modes  distinguish between different isomeric configurations in retinal molecules  distinguish between different isomeric configurations in retinal molecules … Walther et al … Walther et al  finger print of conformational state – benzoic acid  finger print of conformational state – benzoic acid … Walther et al … Walther et al

4. Vacuum capable THz-TDS set-up  useful bandwidth of 0.1- 3.0 THz  spectral resolution of better than 1 cm -1

5. Sample preparation  pellets (1.2-1.4mm) with matrix for low temperature measurements (polyethylene:sample::8:1) measurements (polyethylene:sample::8:1)  pure sample pellets ( 0.3- 0.7mm) for room temperature measurement – to observe distinct peaks measurement – to observe distinct peaks

6. Particle size – ESEM measurement  Submicron particle size – minimise scattering effect on observed spectra

7. Far-infrared absorption in Glucose D-Glucose L-Glucose D-Fructose

8. Dependence on crystallanity  Intermolecular vibrational modes

9. Absorption in molecule containing glucose structure  absorption tend to depend on molecular environment L-Glucose Sucrose

10. L-Glucose - absorption peaks at low temperature  many distinct absorption peaks at low temperature

11. We observed terahertz absorption as a result of intermolecular interaction & also dependence on structural change in a molecule ……… in other molecules?

12. Far-infrared absorption in Uric Acid Uric Acid Allantoin  structural dependence of absorption

13. Temperature dependence  stronger temperature dependence in allantoin  change in energy surfaces of molecules at low temperature Allantoin Uric Acid

14. Uric Acid - absorption line profile  change in position and width of peaks with temperature

15. Conclusions  Demonstrated use of THz-TDS to study far-infrared response of some isomeric and derived structures of glucose and uric acid  Observed absorption due to collective intermolecular modes  Strong temperature and structural dependence of absorption  Theoretical model analysis required to understand the underlying dynamics

16. Acknowledgements EPSRC Royal Society Royal Society Toshiba Research Europe Toshiba Research Europe Association of Commonwealth Universities and thanks to and thanks to Dr. M. B. Johnston Dr. M. B. Johnston Dr. A. Dowd Dr. A. Dowd