Detection of carboxyhemoglobin using Fourier transform infrared microspectroscopy.

We investigated the absorption of carboxyhemoglobin (COHb) using a Fourier transform infrared (FTIR) microscopy system. Weak absorption at 1969 cm-1 due to Fe<--CO and strong absorption due to N-H stretching vibration, > C = O stretching vibration and -NH bending vibration (1544 cm-1) were observed. The ratio of absorbance at 1969 cm-1/1544 cm-1 can be used as an index of CO saturation.