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Journal of Spectroscopy
Volume 2014, Article ID 510890, 5 pages
Research Article

SB-ATR FTIR Spectroscopic Monitoring of Free Fatty Acids in Commercially Available Nigella sativa (Kalonji) Oil

1National Centre of Excellence in Analytical Chemistry University of Sindh, Jamshoro 76080, Pakistan
2Dr. M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro 76080, Pakistan
3Department of Pharmacy, Shaheed Mohtarma Benazir Bhutto Medical University, Larkana, Sindh 77150, Pakistan

Received 28 May 2013; Revised 4 October 2013; Accepted 31 October 2013; Published 21 January 2014

Academic Editor: Khalique Ahmed

Copyright © 2014 S. A. Mahesar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Free fatty acids (FFA) in Nigella sativa (N. sativa) commercial and seed oil were determined using single-bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy. Gravimetrical mixing was done by adding 0.1–40% oleic acids in neutralized N. sativa oil containing 0.1% FFA. FTIR spectroscopy technique and partial least square (PLS) calibration were used to detect the absorption region of carbonyl (C=O) which is in the range of 1690–1727 cm−1. The results of PLS calibration model and root mean square error of calibration (RMSEC) are 0.999 and 0.449, respectively. Comparing the FFA obtained in N. sativa oil by using FTIR with the FFA obtained using AOCS titrimetric method shows a positive correlation and confirms that the described method is a useful procedure.