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Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Typings of Edible Oils through Spectral Networking of Triacylglycerol Fingerprints
摘要： Adulteration of edible oils by the manufacturers has been found frequently in modern societies. Due to the complexity of the chemical contents in edible oils, it is challenging to quantitatively determine the extent of adulteration and prove the authenticity of edible oils. In this study, a robust and simple MALDI-TOF-MS platform for rapid ?ngerprinting of triacylglycerols (TAGs) in edible oils was developed, where spectral similarity analysis was performed to quantitatively reveal correlations among edible oils in the chemical level. Speci?cally, we proposed oil networking, a spectral similarity-based illustration, which enabled reliable classi?cations of tens of commercial edible oils from vegetable and animal origins. The strategy was superior to traditional multivariate statistics due to its high sensitivity in probing subtle changes in TAG pro?les, as further demonstrated by the success in determination of the adulterated lard in a food fraud in Taiwan. Finally, we showed that the platform allowed quantitative assessment of the binary mixture of olive oil and canola oil, which is a common type of olive oil adulteration in the market. Overall, these results suggested a novel strategy for chemical ?ngerprint-based quality control and authentication of oils in the food industry.
关键词： triacylglycerols,oil networking,spectral similarity,adulteration,MALDI-TOF-MS,edible oils
更新于2025-09-11 14:15:04
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A green single-tube sample preparation method for wear metal determination in lubricating oil by microwave induced plasma with optical emission spectrometry
摘要： A straightforward and rapid single-tube sample pretreatment for wear metals determination in used lubricating oils was developed in this work as an alternative to the reference pretreatment method (ASTM). A D-optimal mixture design on a three-component solution was performed. The optimal composition for the proposed sample preparation emulsion was 2 % v/v of xylene, 9.5 % v/v of Triton?X-114 and 88.5 % v/v of H2O. The determination of 18 wear metals was carried out by microwave induced plasma with optical emission spectrometer (MIP OES), and the results of the two sample preparations - conventional and proposed- were statistically compared. Also, a certified standard “wear metals in used lubricating oils” for pretreatment validation was used. The developed method was as effective as the reference method indicated by ATSM, similar in speed and simplicity, but superior from the environmental and economic point of view. The proposed pretreatment allowed Ag, Al, Ba, Ca, Cd, Cr, Cu, K, Mg, Mn, Mo, Ni, Pb, Si, Sn, Ti, V and Zn determination, with LOQ between 1.40 mg kg-1 for Ca and 6.34 mg kg-1 for Pb. The precisions established as the relative standard deviation (RSD) were better than 6.2%. The proposed method avoid sample handling, reducing contamination risks and analyte losses, affording significantly improvement on wear metal quantification.
关键词： Microwave induced plasma atomic emission spectrometry,Mixture experimental design,Wear metals,Green single-tube sample preparation,Used lubricating oils
更新于2025-09-11 14:15:04
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Molecular rotors with long alkyl chains as fluorescent viscosity sensors for hydrocarbon and silicone oil fluids
摘要： Three different tetraphenylethylene derivatives (TPE18, TPE8, TPE1) with different-length alkyl chains (octadecyl, octyl, methyl) were prepared, and their viscosity (η) sensitivities were examined for hydrocarbons and silicone oils. Both TPE18 and TPE8 dissolved in the fluids very well, except for the case of TPE8 in silicone oils, while TPE1 remained undissolved. In order to examine the viscosity sensitivity, the hydrodynamic fluorescence (FL) emission behaviors of TPE18 and TPE8 were investigated. The FL intensity (I) significantly increased as the η of the fluid increased. The relationship between I and η was expressed by the F?rster-Hoffmann equation log I = C + x log η. TPE18 and TPE8 exhibited extremely high x values of 0.63 and 0.70, respectively, for higher alkanes (η 1.34–84.0 cP); the corresponding x values were 0.73 and 0.63 for lower alkanes (η 0.29–1.70 cP). The slight difference in the x value between the two derivatives was due to the difference in their molecular affinity to the fluids. On the other hand, TPE18 dissolved well in silicone oils, while TPE8 did not dissolve completely. The x value of TPE18 was determined to be 0.16, which was much smaller than those for hydrocarbon fluids.
关键词： Molecular rotor,Silicone oils,Viscosity sensor,Fluorescence,Hydrocarbons
更新于2025-09-10 09:29:36
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A multichannel Au nanosensor for visual and pattern inspection of fatty acids
摘要： Fatty acids (FAs) are important dietary sources of fuel for animals and structural components for cells. The number, position and configuration of olefins in the alkyl chains play important roles in the impacts of FAs on human health. Currently, structural profiling of FAs in edible oils and fats is an important issue in nutrition industries and food safety. Due to the lack of distinct functional groups, it is extremely difficult to discriminate FAs with structural difference by facile and in situ sensing methods. A few chemosensors have been developed for shape selective sensing of FAs, but their capability and performance were still limited. Herein, for the first time, we proposed a multichannel Au nanosensor for visual and pattern-generating inspection of FAs based on the highly selective binding ability of Ag+ to olefinic bonds and Ag+ regulable color variation of Au nanoparticles. As a result, the nanosensor showed good selectivity for five FAs with subtle structural difference as low as 5 nM. By further deriving three channel signals in respect of color and color depth, a signature-like signal pattern could be generated by principal component analysis for each FAs and even different FAs mixtures such as edible oils. Hence, structural variation of FAs in edible hot pot oils with heat treatment was successfully monitored by this Au nanosensor in time course. This sensor holds great promise in point-of-care inspection of edible oils and fats.
关键词： Au nanosensor,Colorimetric sensing,Pattern recognition,Edible oils,Fatty acids
更新于2025-09-09 09:28:46
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Refractometric Sensing of Heavy Oils in Fluorescent Core Microcapillaries
摘要： Refractometric Sensing of Heavy Oils in Fluorescent Core Microcapillaries — The refractometric sensing of calibrated heavy oils (density > 1 000 kg/m3) is demonstrated using fluorescent-core microcapillaries. A 25-micron capillary channel was first coated with a high-index layer of fluorescent silicon Quantum Dots (QD). This QD film supports the development of cylindrical Whispering Gallery Mode (WGM) resonances inside the capillary. Heavy oils spanning a wide range of refractive index were pumped into the capillary channel, causing large shifts in the fluorescence WGM resonant wavelengths. The sensitivity for heavy oils approached 250 nm per Refractive Index Unit (nm/RIU) at the higher oil indices, which is the highest sensitivity so far observed for a refractometric sensor operating in the fluorescence mode. This suggests that fluorescent core microcapillaries may be a viable microfluidic alternative for refractometric or chemical sensing in various stages of oil and gas processing, monitoring and usage.
关键词： Fluorescent core microcapillaries,Heavy oils,Quantum Dots,Refractometric sensing,Whispering Gallery Mode
更新于2025-09-04 15:30:14