Assessment of diffusion coefficients of general solvents by PFG-NMR: investigation of the sources error.
Accurate measurements of the diffusion coefficients, including an estimate of uncertainty, of various solvent molecules using the PFG-NMR method were performed in this study. Accurate diffusion coefficients were obtained using the Shigemi NMR tube. The relative combined standard uncertainties of the diffusion coefficients were found to be within approximately 0.4%. The three uncertainty sources (signal decay of the standard and the solvent, and diffusion coefficient of standard) equally affect the combined standard uncertainties. Unreliable data were obtained using a normal NMR tube, indicating that convection and background gradient effects significantly affected the accurate measurement of the diffusion coefficients.
Polymer Standards Section, National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan. h-kato@aist.go.jp
Haruhisa
H
Kato
Takeshi
T
Saito
Mami
M
Nabeshima
Kayori
K
Shimada
Shinichi
S
Kinugasa