|Luthria, Devanand - Dave|
Submitted to: Journal of the Association of Official Analytical Chemists
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/10/2011
Publication Date: 5/1/2012
Citation: Chanthai, S., Prachakool, S., Ruangviriyachai, C., Luthria, D.L. 2012. Influence of extraction methodologies on the analysis of five major volatile aromatic compounds of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) grown in Thailand. Journal of the Association of Official Analytical Chemists. 95:763-772. Interpretive Summary: This paper describes the significance of chemical extraction procedures and conditions for the analysis of compounds from citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus). The analyses for this study were done by collaborators in Thailand. Two methods of analysis were compared systematically: classical micro-hydrodistillation (MHD) with modern accelerated solvent extraction (ASE). These two methods were used to extract five volatile aromatic compounds from the two types of grass (citronellal, citronellol, geraniol, citral, and eugenol). The data presented in this manuscript will be of interest for the researchers, food producers, nutrition community, and consumers.
Technical Abstract: Infusions of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) have been commonly used in folk medicine in Thailand and other Asian countries. This study focuses on a systematic comparison of two extraction methods for major volatile aromatic compounds (VACs) of citronella grass and lemongrass: classical micro-hydrodistillation (MHD) as well as modern accelerated solvent extraction (ASE). Sixteen VACs were identified by gas chromatography-mass spectrometry (GC-MS). Gas chromatography with flame ionization detection (GC-FID) was used for the quantification of five VACs, (citronellal, citronellol, geraniol, citral, and eugenol) to compare the extraction efficiency of two different methods. Linear range, limit of detection (LOD), and limit of quantization (LOQ) were calculated for the five VACs. Intra-day and inter-day precisions for the analysis of VACs were determined for each sample. The extraction recovery as calculated by the spiking experiment with known standards of VACs (%) by MHD and ASE ranged from 64.9-91.2, and 74.3-95.2, respectively. The extraction efficiency of VACs was compared for three solvents (hexane, dichloromethane, and methanol) of varying polarities, seven different temperatures (ranging from 40°C to 160°C with a gradual increment of 20°C), five time periods (from 1-10 min), and three cycles (from 1, 2, and 3 repeated extractions). Optimum extraction yields of VACs were obtained when extractions were carried out for seven minutes with dichloromethane and two extraction cycles at 120°C. The results show that the ASE technique is more efficient than MHD, as it results in improved yield and significant reduction in extraction time with automated extraction capabilities.