Rapid identification of CCA-treated wood using laser-induced breakdown spectroscopy

As chromated copper arsenate (CCA) contains copper, chromium and arsenic, waste CCA-treated wood must be separated from other treated wood because of environmental pollution by chromium and arsenic when it is incinerated and the regulation. Therefore, a method to identify CCA-treated wood was developed using laser-induced breakdown spectroscopy (LIBS). Using the LIBS apparatus assembled in our laboratory, plasma on a wood surface was generated by a 4 ns pulse of 1064 nm (55 mJ/mm(2)) emitted from Nd:YAG laser. Fluorescence from the plasma was collected by an ellipsoidal mirror and analyzed by a spectrometer in the range of 190-300 nm. The results showed that the 228.7 nm line from As and 267.6 nm line from Cr were useful for the identification of CCA-treated wood. As the discrimination capacity was confirmed by the elemental composition analysis by X-ray fluorescence, it was concluded that LIBS can specifically identify CCA-treated wood.