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

alpha-Pinene and beta-myrcene are compounds that are contained in mastic gum in high concentrations. The beta-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 alpha-pinene and beta-myrcene content in mastic gum. Bands at 1658 and 1633 cm(-1) were used for the calibration of alpha-pinene and beta-myrcene, respectively. Calibration curves were linear (correlation coefficient for alpha-pinene was 0.992 and 0.997 for beta-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% alpha-pinene and 4.5-57.9% beta-myrcene. (C) 2002 Elsevier Science Ltd. All rights reserved.