Analytical Sciences

Abstract − Analytical Sciences, 33(11), 1211 (2017).

Estimation of Retention Time in GC/MS of Volatile Metabolites in Fragrant Rice Using Principle Components of Molecular Descriptors
Nataporn WIJIT,*1 Sukon PRASITWATTANASEREE,*2 Sugunya MAHATHEERANONT,*1 Peter WOLSCHANN,*3,*4 Supat JIRANUSORNKUL,*5 and Piyarat NIMMANPIPUG*1
*1 Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science and Graduate School, Chiang Mai University, Chiang Mai 50200, Thailand
*2 Department of Statistics, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
*3 Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna 1090, Austria
*4 Institute of Theoretical Chemistry, University of Vienna, Vienna 1090, Austria
*5 Department of Pharmaceutical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
A quantitative structure–retention relationship (QSRR) study was applied for an estimation of retention times of secondary volatile metabolites in Thai jasmine rice. In this study, chemical components in rice seed were extracted using solvent extraction, then separated and identified by gas chromatography–mass spectrometry (GC-MS). A set of molecular descriptors was generated for these substances obtained from GC-MS analysis to numerically represent the molecular structure of such compounds. Principal component analysis (PCA) and principal component regression analysis (PCR) were used to model the retention times of these compounds as a function of the theoretically derived descriptors. The best fitted regression model was obtained with R-squared of 0.900. The informative chemical properties related to retention time were elucidated. The results of this study demonstrate clearly that the combination of molecular weight and autocorrelation functions of two dimensional interatomic distance, which are molecular polarizability, atom identity, sigma charge, sigma electronegativity and polarizability, can be considered as comprehensive factors for predicting the retention times of volatile compounds in rice.