Detection of adulteration of sesame and peanut oils via volatiles by GC × GC–TOF/MS coupled with principal components analysis and cluster analysis

The method of headspace coupled with comprehensive two‐dimensional GC–time‐of‐flight MS (HS‐GC × GC–TOF/MS) was applied to differentiate the volatile flavor compounds of three types of pure vegetable oils (sesame oils, peanut oils, and soybean oils) and two types of adulterated oils (sesame oils and peanut oils adulterated with soybean oils). Thirty common volatiles, 14 particular flavors and two particular flavors were identified from the three types of pure oils, from the sesame oils, and from the soybean oils, respectively. Thirty‐one potential markers (variables), which are crucial to the forming of different vegetable oil flavors, were selected from volatiles in different pure and adulterated oils, and they were analyzed using the principal component analysis (PCA) and cluster analysis (CA) approaches. The samples of three types of pure vegetable oil were completely classified using the PCA and CA. In addition, minimum adulteration levels of 5 and 10% can be differentiated in the adulteration of peanut oils and sesame oils with soybean oils, respectively. Practical applications: The objective was to develop one kind of potential differentiated method to distinguish high cost vegetable oils from lower grade and cheaper oils of poorer quality such as soybean oils. The test result in this article is satisfactory in discriminating adulterated oils from pure vegetable oils, and the test method is proved to be effective in analyzing different compounds. Furthermore, the method can also be used to detect other adulterants such as hazelnut oil and rapeseed oil. The method is an important technical support for public health against profit‐driven illegal activities.     

Rapid method for analysis of sphingomyelin by microwave derivatisation for gas chromatography–mass spectrometry

Esterification and transesterification of lipids using boron trifluoride in methanol is widely used in lipid chemistry to study fatty acid (FA) profiles of various lipids by GC–MS. Transesterification of the FAs in sphingolipids is a difficult and time‐consuming task. A rapid and convenient method for preparation of FAMEs from sphingomyelin (SM) using microwaves (MWs) was developed for GC–MS analysis. Experiments with three levels of power were performed and the yields were compared at regular time intervals. The maximum yields for all power levels were the same, but the time to reach these yields varied with the power. It was found that at a power of 70 W the maximum yield was reached after 27 min having a stable time window of 8 min for this yield. Practical applications: The technique presented here enables a rapid and easy method for preparing FAMEs from SM by the use of a MW reactor. The reaction time has been reduced from several hours down to only 27 min, with excellent yields.     

Determination of Dodecanol and Short‐Chained Ethoxylated Dodecanols by LC–MS/MS (with Electrospray Ionization) After Their Derivatization (with Phenyl Isocyanate)

This report describes the application of LC–MS/MS for the separation of dodecanol (C₁₂OH) and homogenous fatty alcohols ethoxylated (AE) containing a dodecyl moiety and 1–9 ethoxy groups. These ethoxylates and free alcohol were derivatized for LC–MS/MS analysis with phenyl isocyanate (PIC). The derivatives of analytes with PIC were separated using a C18 column. Gradient elution with a mixture of ethyl acetate and acetonitrile (5 mM) was employed. The described determination method is characterized by low detection limits (range from 0.005 µg L^?1 for: C₁₂OH, C₁₂EO_2–7 to 1 µg L^?1 for C₁₂EO₁) and quantification limits (range from 0.01 µg L^?1 for: C₁₂EO_5–7 to 2 µg L^?1 for C₁₂EO₁). The developed and validated method was used in combination with liquid–liquid extraction (using ethyl acetate) in order to identify and quantitatively determine the C₁₂OH and C₁₂EO_1–9 present in environmental samples collected from Warta river water in Poznan.     

Monitoring of Fat Content,Free Fatty Acid and Fatty Acid Profile Including <Emphasis Type="Italic">trans</Emphasis> Fat in Pakistani Biscuits

The fat contents of 12 brands of biscuits were extracted and evaluated for free fatty acids (FFA) and their fatty acid composition (FAC). The oil content and FFA varied from 13.7 to 27.6% and 0.2 to 1.0%, respectively. The FAC was analyzed by gas chromatography–mass spectroscopy with particular emphasis on trans fatty acids (TFA). Total saturated, unsaturated, cis-monounsaturated and polyunsaturated fatty acids were determined in the range of 37.9–46.9, 53.0–62.0, 12.3–43.7 and 0.1–9.2%, respectively. The high amount of TFA was observed in all biscuit samples and varied from 9.3 to 34.9%. The quantity and quality of the lipid fraction of the biscuits indicated that the all analyzed biscuits are a rich source of fat, saturated fatty acids and trans fatty acids, consequently not suitable for the health of consumers. The high content of trans fatty acids and palmitic acid also indicated that blends of RBD palm oil and partially hydrogenated oil had been used in the biscuit manufacturing.     

Aqueous and Solvent‐Free Uncatalyzed Three‐Component Vinylogous Mukaiyama–Mannich Reactions of Pyrrole‐Based Silyl Dienolates

A catalyst‐free, environmentally benign three‐component vinylogous Mukaiyama–Mannich reaction of pyrrole‐based silyl dienolates is presented, which works effectively in both aqueous and solvent‐free environments. Both lipophilic and hydrophilic aldehyde candidates are suitable substrates, allowing access to a rich repertoire of unsaturated vicinal aminolactam structures with virtually complete γ‐site selectivity and moderate to good anti‐diastereoselectivity. The utility of this technology is highlighted by protecting group‐free synthesis of densely hydroxylated, sugar‐related lactam frameworks. The role of water as an indispensable H‐bonding reaction propeller is demonstrated.     

Hafnium Chloride Tetrahydrofuran Complex‐Catalyzed Diels–Alder Cycloadditions of 3‐Ethoxycarbonylcoumarins with 1,3‐Dienes under Solvent‐Free Conditions

Hafnium chloride tetrahydrofuran complex (HfCl₄⋅2 THF) is an efficient catalyst for the Diels–Alder cycloadditions of 3‐ethoxycarbonylcoumarins 1a – c and 1,3‐butadienes 2x – z under solvent‐free conditions furnishing the corresponding cycloadducts in excellent yields. This salt is an air stable Lewis acid and therefore the reactions can be performed in air atmosphere making the procedure simple to be carried out.