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We developed and validated a fast UHPLC-ESI-MS/MS in combination with one step salting-out assisted liquid-liquid extraction (SALLE) for high throughput analysis of 12 isoflavones in soy milks. Conventional sample preparation requires two steps composing time-consuming freeze-drying (72h) and solvent extraction (2h). The SALLE required only about 40min, which was over 100times faster without compromising the extraction efficiency. The baseline separation of 12 isoflavones was achieved in 2.5min by the UHPLC-MS/MS which is the fastest chromatographic method ever reported. The new method was fast, simple, selective, sensitive, precise and accurate. The method was successfully applied to 22 commercial soy milks for the high throughput analysis of isoflavones. The new method would be a fast, simple, reliable, and useful measure for the analysis of isoflavones in soy milk especially in the laboratories facing the challenges of saving the analytical time, labor cost and solvent usage., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A new headspace (HS)-solid phase microextraction (SPME)-gas chromatography-tandem quadrupole mass spectrometry (GC-MS(2)) was established for the simultaneous characterization and quantitation of pyrazines in perilla seed oils. HS-SPME conditions such as fiber choice, extraction temperature, and adsorption times were tested. The established GC-MS(2) showed low detection limit (LOD) and high specificity, recovery, and precision for analysis of pyrazines in perilla seed oils. The LODs for the pyrazines were in the range of 0.07-22.22 ng/g oil. The relative standard deviations (RSDs) for the intra- and interday repeated analyses of pyrazines were less than 9.49 and 9.76%, respectively. The mean recoveries for spiked pyrazines in perilla seed oil were in the range of 94.6-107.92%. Perilla seed oils were obtained by mechanical pressing from perilla seeds roasted to different degrees of roasting (mild, medium, medium dark, and dark roasting). Fourteen pyrazine compounds in perilla seed oils were isolated, identified, and quantitated. Among them, 2-methyl-3-propylpyrazine, tetramethylpyrazine, and 2,3-diethyl-5-methylpyrazine were the first identified in perilla seed oils. Degree of roasting influenced greatly the composition and contents of pyrazines in perilla seed oils. In light-roasted perilla seed oil, 2,5-dimethylpyrazine was the most predominant pyrazine. However, in dark-roasted perilla seed oil, 2-methylpyrazine was the most abundant pyrazine in the oil, representing 38.3% of its total pyrazine content. Dark-roasted perilla seed oil contains 16.78 times higher quantity of pyrazines than light-roasted perilla seed oil. This represents the first report on the quantity of pyrazines in perilla seed oils.

Reportedly policosanols (PCs) have various beneficial functionalities on health. A gas chromatography-tandem mass spectrometry (GC-MS/MS) with a low limit of detection (LOD), and high specificity, recovery, and precision was successfully established for the PC analysis in vegetable oils. The LODs for the PCs were in the range of 0.002 to 0.016 μg/mL. The relative standard deviation (RSD) for the repeated analysis of PCs was less than 3.356%. The mean recoveries for spiked heptacosanol and octacosanol in vegetable oil were 102.3% and 106.3%, respectively. The total PC contents in the vegetable oils varied from 3.01 to 427.83 mg/kg oil. Perilla seed, grape seed, and rice bran oils were found to be highly rich sources of PCs, containing 427.83, 245.15, and 171.17 mg PCs/kg oil, respectively. Corn, sesame, and soybean oils contained only a negligible quantity of PCs. The PC composition in vegetable oils was greatly source dependent. In perilla seed oil, octacosanol was the single most predominant component, representing 55.93% of the total PC. In grape seed oil, however, hexacosanol is the most abundant PC, followed by octacosanol, tetracosanol, and triacontanol in a decreasing order. The major PCs in rice bran oil were triacontanol, octacosanol, hexacosanol, and tetracosanol, which constituted over 87.3% of the total PC. This represents the 1st report on the composition and contents of PC in most vegetable oils analyzed here. Practical Application: The information might be used for the development of vegetable oil products with beneficial functionality. [ABSTRACT FROM AUTHOR]

Policosanol (PC) is a mixture of health promoting bioactive long-chain aliphatic alcohols. Here, we report that green tea ( Camellia sinensis ) leaves are the exceptionally rich plant-sources of PC. Young and tender leaves and old and turf leaves of C. sinensis were hand-picked in spring and autumn. The total contents of PC in the leaves were in the range of 726.2–1363.6 mg/kg as determined by a GC–MS/MS. The compositions of PC in the leaves were different with harvest season and types. The total contents of PC in commercial green tea leaves were found to be in the range of 856.7–1435.1 mg/kg. Interestingly, the infused green tea leaves contained the higher PC than the non-infused green tea product, reaching to 1629.4 mg/kg. This represents the first report on the contents and compositions of PC in green tea leaves, showing unambiguous evidence of their potential as rich sources of PC. [ABSTRACT FROM AUTHOR]