Quantitative analysis of α-pinene and β-myrcene in mastic gum oil using FT-Raman spectroscopy

α-Pinene and β-myrcene are compounds that are contained in mastic gum in high concentrations. The β-myrcene percentage determines the marketability of mastic gums. The chemical composition of mastic gum oil of a representative resin quality was evaluated by gas chromatography–mass spectrometry (GC–MS) technique. FT-Raman spectroscopy, based on band intensity measurements, was used for the determination of α-pinene and β-myrcene content in mastic gum. Bands at 1658 and 1633 cm−1 were used for the calibration of α-pinene and β-myrcene, respectively. Calibration curves were linear (correlation coefficient for α-pinene was 0.992 and 0.997 for β-myrcene) in the range 30–80 and 3–45%, respectively. Normalization of calibration curves, against the 802 cm−1 cyclohexane band, minimized the effect of laser beam power fluctuations. The proposed method is rapid and simple. Accordingly, mastic gum oils from Chios island (Greece) contained 38.1–69.5% α-pinene and 4.5–57.9% β-myrcene.