Raman microscopy for the quantitation of propiconazole in white spruce

The Raman signature of propiconazole at 647–693 cm⁻¹ was used to determine the propiconazole distribution in white spruce (Picea glauca). Samples treated with propiconazole were milled at ~1.5 mm intervals and analysed by methanol extraction and GC-MS to obtain a depth profile in the longitudinal direction. The concentration of propiconazole in the milled wood layers ranged from 0.5 to 7.3 mg/g (dry mass wood). The average Raman signal from each of the layers was linear (R ²=0.933) with the GC-MS-determined concentrations. The effective detection limit (concentration producing a signal three times the standard deviation) was 1.0 mg/g. The standard deviation of the method was approximately 0.3 mg/g.