. Various samples were recorded with a FTIR spectrometer(Nicolet iS 10, Thermo Fisher Scientific, USA) by collecting 32 accumulative scan in 500 cm− 1 to 4000 cm− 1 region against a blank KBr pellet background. The spectral resolution of FTIR spectrometer was superior to 0.4 cm− 1.
2.6 ฟูเรียร์อินฟราเรด (FTIR) การวิเคราะห์สเปกตรัม