Abstract
An NMR technique to measure exchange kinetics at thermal equilibrium in dispersions of moderately soluble crystalline material is presented. By monitoring the exchange of molecules between pools in solid and dissolved form, one can characterize the surface specific exchange rate. Illustrative experiments were performed in a model system with β-type crystals of tripalmitin as the solid phase and tripalmitin, a fraction of it deuterated, dissolved in a medium-chain TG oil as the liquid phase. The concentration of deuterated tripalmitin in the solvent was followed by 2H NMR after the crystals, which initially lack deuterated tripalmitin, were immersed in the liquid. The variation of the 2H concentration in the solvent provided the surface specific exchange rate. No systematic errors, due to the slight difference in properties of the deuterated tripalmitin compared to hydrogenated tripalmitin, were observed. The methodology worked well between crystal concentrations of 2 and 4 wt%.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Sato, K., S. Ueno, and J. Yano, Molecular Interactions and Kinetic Properties of Fats, Progress Lipid Res. 38:81–116 (1999).
Raschke, T.M., and S. Marqusee, Hydrogen Exchange Studies of Protein Structure, Curr. Opinion Biotechnol. 9:80–86 (1998).
Das, H.A., and R.D. Van Der Weyden, Isotopic Exchange Measurements in Batch Adsorption and Desorption Measurements, J. Radioanal. Nucl. Chem. 191:229–238 (1995).
Haghshenas, N., P. Smith, and B. Bergenståhl, The Exchange Rate Between Dissolved Tripalmitin and Tripalmitin Crystals, Colloids Surf. B 21:239–243 (2001).
Mansfield, P.B., A New Wide-Line NMR Analyzer and Its Use in Determining the Solid-Liquid Ratio in Fat Samples, J. Am. Oil Chem. Soc. 48:4–6 (1971).
Haighton, A.J., L.F. Vermaas, and C. den Hollender, Determination of the Solid-Liquid Ratio of Fats by Wide-Line Nuclear Magnetic Resonance, 48:7–10 (1971).
van Putte, K., L. Vermaas, J. van den Enden, and C. den Hollander, Relationship Between Pulsed NMR, Wide-Line NMR and Dilatometry, 52:179–181 (1975).
Norris, R., and M.W. Taylor, Comparison of NMR and DSC Methods for the Estimation of Solid Fat Content, N.Z. J. Dairy Sci. Technol. 12:160–165 (1977).
Simoneau, C., M.J. McCarthy, R.J. Kauten, and J.B. German, Crystallization Dynamics in Model Emulsions from Magnetic Resonance Imaging, J. Am. Oil Chem. Soc. 68:481–487 (1991).
Simoneau, C., M.J. McCarthy, D.S. Reid, and J.B. German, Influence of Triglyceride Composition on Crystallization Kinetics of Model Emulsions, J. Food Eng. 19:365–387 (1993).
Ozilgen, S., C. Simoneau, J.B. German, M.J. McCarthy, and D.S. Reid, Crystallization Kinetics of Emulsified Triglycerides, J. Sci. Food Agric. 61:101–108 (1993).
Eads, T.M., A.E. Blaurock, R.G. Bryant, D.J. Royand, and W.J. Croasmun, Molecular Motion and Transitions in Solid Tripalmitin Measured by Deuterium Nuclear Magnetic Resonance, J. Am. Oil Chem. Soc. 69:1057–1068 (1992).
Timms, R.E., Heats of Fusion of Glycerides, Chem. Phys. Lipids 21:113–129 (1978).
van Miltenburg, J.C., and E. ten Grotenhuis, A Thermodynamic Investigation of Tripalmitin. Molar Heat Capacities of the α-and β-Form Between 10 K and 350 K, J. Chem. Eng. Data 44: 721–726 (1999).
Atkins, P.W., Physical Chemistry, 6th edn., Oxford University Press, Oxford, United Kingdom, 1998.
Lounila, J., K. Oikarinen, P. Ingman, and J. Jokisaari, Effects of Thermal Convection on NMR and Their Elimination by Sample Rotation, J. Magn. Reson. A 118:50–54 (1996).
Abragam, A., The Principles of Nuclear Magnetism, Clarendon, Oxford, United Kingdom, 1961.
Schmidt-Rohr, K., and H.W. Spiess, Multidimensional Solid-State NMR and Polymers, Academic Press, London, 1994.
Press, W.H., B.P. Flannery, S.A. Teukolsky, and W.T. Vetterling, Numerical Recipes, Cambridge University Press, Cambridge, United Kingdom, 1986.
Johansson, D., and B. Bergenståhl, The Influence of Food Emulsifiers on Fat and Sugar Dispersions in Oils. 1. Adsorption, Sedimentation, J. Am. Oil Chem. Soc. 69:705–717 (1992).
Lifshitz, I.M., and V.V. Slyozov, The Kinetics of Precipitation from Supersaturated Solid Solutions, J. Phys. Chem. Solids 19:35–50 (1961).
Mullin, J.W., Crystallization, 4th edn., Butterworth-Heinemann, Oxford, United Kingdom, 2001.
Author information
Authors and Affiliations
About this article
Cite this article
Löfborg, N., Smith, P., Furó, I. et al. Molecular exchange in thermal equilibrium between dissolved and crystalline tripalmitin by NMR. J Amer Oil Chem Soc 80, 1187–1192 (2003). https://doi.org/10.1007/s11746-003-0840-8
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11746-003-0840-8