FTIR Analysis of Irvingia gabonensis Kernel Oil (IGKO)
The result in Fig. 17 was analyzed and compared with known signature of identified materials in the FTIR library [71]. For the IGKO sample (Fig. 17), the peak center at 900.7966 cm-1 is characteristics of P – F stretching, indicating the presence of phosphorus compounds. The peak at 1047.5 cm-1 is a characteristic of C – O stretching, indicating the presence of alcohol and phenol, which are oxygen-containing compounds. For the peak at 1369.536 cm-1, it is a characteristic of aromatic nitro compound NO2 stretching, which is an indication of the presence of nitrogen-containing compounds. The peaks centers at 1473.258 cm-1and 1664.323 cm-1, are characteristics of C = C stretching and nitrite N – O stretching, respectively, indicating the presence of aromatic compounds and nitrogen-containing compounds, respectively. In a similar way, the peak at 2020.284 cm-1 is characteristics of combination N – H stretching, combination O – H stretching, indicating the presence of organic compounds. The peaks at 2353.372 cm-1 and 2659.711 cm-1 are characteristics of phosphorus acid/ester P – H stretching and phosphorus acid/ester O – H stretching, respectively, which are indications of the presence of phosphorus compounds. Also, the peaks centered at 3002.457 cm-1 and 3289.143 cm-1 are characteristic of O – H stretching, indicating the presence of carboxylic acids, which are oxygen-containing compounds and water. Lastly, the peak at 3772.403 cm-1 is beyond the infrared band of 3700 wavenumber (cm-1) for organic compounds as such, could not be identified.