Boron-11 nuclear magnetic resonance imaging and spectroscopy have been used to characterise the nature and distribution of boron compounds after preservative treatment of radiata pine wood with trimethylborate (TMB). One day after treatment, 11B magnetic resonance imaging microscopy showed significant differences in the morphological distribution of boron species, with there apparently being no treatment penetration of the latewood. 11B MAS NMR spectroscopy of freshly preservative-treated radiata pine wood, which had been separated into latewood and earlywood, showed the only boron species present in the latewood to be boric acid while in the earlywood both TMB and boric acid were initially present. Due to quadrupolar broadening and a short T2 value, the boric acid signal relaxed too quickly to be observable and this caused the apparent lack of 11B in the image when only boric acid was present. TMB undergoes hydrolysis to form boric acid and in radiata pine latewood, this hydrolysis reaction is rapid.
[1]
A. MacKay,et al.
Radial moisture profiles of cedar sapwood during drying : a proton magnetic resonance study
,
1990
.
[2]
J. Rocha,et al.
The reaction of boric acid with wood in a polystyrene matrix
,
1996
.
[3]
K. Hayamizu,et al.
Shift References in High-Resolution Solid-State NMR
,
1989
.
[4]
George W. Kabalka,et al.
A method for imaging nuclei with short T2 relaxation and its application to boron-11 NMR imaging of a BNCT agent in an intact rat
,
1990
.
[5]
G. Maciel,et al.
High-speed MAS NMR spectra of quadrupolar nuclides at high magnetic fields
,
1990
.
[6]
P. Callaghan.
Principles of Nuclear Magnetic Resonance Microscopy
,
1991
.