Quantifying Propiconazole in Wood by Raman Microscopy

Raman spectra of wood blocks treated with different propiconazole solutions (4%, 2% and 1%) in mineral spirits were recorded using a Raman microscope, equipped with a NIR (785nm) laser. The strong propiconazole Raman band, in the uncongested region 647-693 cm-1 was chosen as the analytical band. The normalized intensity of analytical band was used to determine the propiconazole distribution in white spruce. Mapping measurements on radial face of the treated samples revealed that on average the propiconazole concentration in summerwood was much higher than concentration in springwood. CG-MS analyses were ccarriedout on methanol extractions of soaked samples milled at ~1.5 mm intervals. The depth profiles in longitudinal directions, obtained by Raman and GC-MS measurements, suggested that propiconazole tended to bloom to the surface during drying. A linear calibration plot was produced from averaged Raman normalized intensity and GC-MS-measured concentrations. By using the regression line, concentration in the longitudinal direction was predicted for another wood block soaked in 3% propiconazole solution.