|Title||Quantification of mobilized copper(II) levels in micronized copper-treated wood by electron paramagnetic resonance (EPR) spectroscopy|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Xue, W, Kennepohl, P, Ruddick, JNR|
Sapwood sawdust from southern pine was treated with micronized copper (MC) under various conditions and the mobilized copper(II) (Cumob.) levels determined in the treated wood by electron paramagnetic resonance (EPR) spectroscopy. The spectral parameters for copper sulphate treated sapwood and those of MC treated sapwood were very similar. A linear correlation was found between the intensities of Cu-EPR spectra and those of Cu-XRF (energy dispersive X-ray fluorescence spectroscopy) in a series of copper sulphate treated sapwood reference samples. Thus the EPR signal intensities could be reliably correlated to the mass of reacted copper present using this calibration curve. The amount of the Cumob. in sawdust treated by MC suspensions increased during the first 2 to 3 days after the initial treatment and then reached a maximum during the 7-day monitoring period. In case of the treatment with micronized copper alone or micronized copper azole (MCA), the elevated MC concentration led to an elevated amount of copper (to about 0.23% Cu ) solubilised by the sapwood. If wood was treated with micronized copper quat (MCQ), the Cumob. initially increased, but at higher concentrations, the Cumob. content decreased, due to interference by the quat co-biocide on the acid reaction by wood on the basic copper carbonate. Examination of commercially treated wood confirmed the laboratory observations.