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The volatile compound 6-methyl-5-hepten-2-one (MHO) is an important chemical intermediate and flavor component derived from carotenoid during fruit metabolism, which is important factor impacting consumer-liking. Fruit has complex matrix and is difficult to be purified during MHO analysis. A rapid liquid–liquid extraction-gas chromatography–mass spectrometry (LLE-GC–MS) method was developed for effective determination of MHO in fruit in this study. The calibration curves for MHO showed high linearity in the range of 100–2000 ng/ml with internal standard method. The limit of detection (LOD), limit of quantification (LOQ) were both <100 ng/ml. Real samples of tomato cultivar fruit were analyzed and RSD of biological replicates varied in the range of 2.01% to 12.59%. MHO showed varied content in different tomato fruit tissues of the selected cultivars, in addition to the variation between cultivars. Furthermore, the possible fragmentation patterns were proposed for the main characteristic ions of MHO and internal standard, based on isolation of the fragment ions after the precursor ion underwent splitting at the electron impact ion source. Compared with reported solid-phase microextraction (SPME)-GC–MS method, the validated method was more rapid, precise, accurate and low cost for MHO quantitation. [ABSTRACT FROM AUTHOR]

Determination of volatile organic compounds (VOCs) in crude oil, such as super volatile organic compounds (super VOCs) and simple polycyclic aromatic hydrocarbons (PAHs), is vital for targeting crude oil spill spots. In this study, a static headspace gas chromatography flame ionization detection method was established for determination of super VOCs in crude oil with both external and internal standard determination, which can be used in the field when using portable gas chromatography. Identification was done by comparing the retention time with the corresponding standards and quantitation was done with a new one-drop method. Another simplified and efficient method was performed to analyze volatile PAHs in crude oil, which can also be used in field analysis. Toluene was used as the extraction solvent for PAHs in crude oil. Method validation for both analyses was satisfactory. The result showed that n-butane and n-pentane were maximum super VOCs and naphthalene, phenanthrene and fluorene were the main PAHs in the crude oil studied. The super VOCs quantity ranged from 3 to 6% and the main PAHs consisted of 0.02-0.06% of studied crude oil., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)