Curve fitting gives the self-diffusion coefficient (D) as the other
parameters are known (γ = gyromagnetic ratio = 4.258 ×
103 s-1 G-1). DOSY
plots are processed in 2D through a Laplace transform. The 2D
presentation has diffusion coefficients D along the y-axis and chemical
shift along the x-axis (Figure S2 ).
Diffusion of D2O:H2O (1:1 v/v) standard
with known D (2.1 x 10-9 m2/s at
25°C was routinely examined to calibrate G and ensure reproducible
experimental conditions, Gcal value = 0.00190 G/cm/DAC. DOSY observation
time (Δ) was fixed, usually at 140 ms. Plots of echo intensity I
(y-axis) versus the gradient area squared
(γGzδ)2(∆-δ/3) in
ns/m2 (x axis) yielded D, Figure S3.