In Situ Depth Profiling of Complex Film by Fourier Transform Infrared Photoacoustic Spectroscopy / 分析化学

ABSTRACT

Soil particles are very heterogeneous in microscopic scale, which is manifested the double-layer structure made of the soil organic matter and mineral matter. In this work, Fourier by transform infrared photoacoustic spectroscopy ( FTIR-PAS) combined with independent component analysis ( ICA) was utilized for in situ depth-profiling of the manmade complex film, in order to lay a foundation of in situ characterizing the heterogeneous soil organic-mineral complex. The complex film was composed of the PE preservative film and office adhesive tape. The moving velocity of infrared photoacoustic spectrometer was set to 0. 16 cm/s, 0. 32 cm/s and 0. 64 cm/s, respectively. Independent component analysis ( ICA ) was performed on the photoacoustic spectra of the heterogeneous complex film. Results showed that the depth-resolved information of the complex film could be derived by changing the moving velocity, and the estimated thickness of PE film was 5. 4-7. 6 μm, which was close to the actual thickness 7 ± 1 μm. Moverover, the spectral features of the polyethylene ( PE) preservative film and office adhesive tape were extracted from the photoacoustic spectra of the heterogeneous complex film by means of ICA. Depth profiling of complex film samples showed that FTIR-PAS could be used as a new analytical tool to study heterogeneous soils, especially soil organic-mineral complexes.