JOURNAL OF FOOD SCIENCE
·
2016
·Vol. 81
·期 6
·C1370
·
IF 1.649
Chen Jiang,Yuyun Lu,Zhuo Li,Cunzhi Li,Rian Yan
en A series of novel l -ascorbyl fatty acid esters were synthesized by catalization of Novozym ® 435 under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l -ascorbyl saturated fatty acid esters were better than that of tert-butylhydroquinone. The induction period in lipid oxidation of l -ascorbyl saturated fatty acid esters and tert-butylhydroquinone were longer than that of l -ascorbyl unsaturated fatty acid esters and l -ascorbic acid both in soybean oil and lard. Besides, the l -ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l -ascorbic acid, and the l -ascorbyl saturated fatty acid esters were more stable than l -ascorbyl unsaturated fatty acid esters in ethanol solution. Practical Application pt l -Ascorbyl fatty acid esters, with good solubility in hydrophobic conditions, showed similar or even better antioxidant activity and stability than l -ascorbic acid. They could be used to replace the traditional antioxidants in food and cosmetic industry.
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高影响因子
ENERGY AND BUILDINGS
·
2017
·
IF 4.067
Zhao Wang,Guixiang Ma,Shang Liu,Yan Jing,Jinhe Sun,Yongzhong Jia
The thermal properties of caprylic acid, nonanoic acid and their binary system were investigated by differential scanning calorimetry (DSC). The phase diagram for the binary system was constructed, and the experiment results showed that the eutectic temperature and the molar fraction of caprylic acid for the eutectic mixture are 1.83 °C and 0.483, respectively. To satisfy the application demands of the temperature scope from 5 °C to 15 °C, another binary mixture for the binary system with a molar fraction of 0.814 for caprylic acid component is found successfully, and it has good thermal properties that the melting temperature and the latent heat are 7.6 °C and 123 J g −1 , respectively. What is more, the latent heat and melting temperature for the binary mixture do not change at all nearly after being cycled 100 times during the whole melting process. As a novel phase change material (PCM) for application in the field of air conditioning and cooling, the binary mixture has own unique thermal advantages.
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JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES
·
2015
·
IF 0.606
Peijin Wang,Xiaoyan Qiu,Yaling Yang
A novel vortex-assisted dispersive liquid–liquid microextraction method based on floating organic acid (VA-DLLME-FOA) droplet combined with high-performance liquid chromatography-fluorescence detection was successfully developed for extraction and preconcentration of three estrogens (estriol (E3), 17β-estradiol (βE2), and estrone (E1)) in human urine. In this method, estrogens were extracted into fine droplets of nonanoic acid, which floated on the top of the sample solution. Vortex-mix instead of organic dispersive solvent was applied to assist the dispersion of the extraction solvent into aqueous samples; due to the elimination of dispersive solvent, high extraction efficiency and enrichment factor could be achieved. Factors affecting VA-DLLME-FOA (type and volume of the extraction solvent, sample pH, vortex-mix time, and centrifugation) were optimized. The relative standard deviations (RSD%, n = 5) were 1.56–2.98% and the limits of detection were 0.01 ng mL−1 for E3, 0.01 ng mL−1 for βE2, and 0.06 ng mL−1 for E1. Recoveries of the estrogens in spiked human urine samples were in the range of 96.8–102.3%. The results showed that VA-DLLME-FOA was a simple, sensitive, low-cost, minimum organic solvent consumption and efficient analytical method for the separation and determination of estrogens in human urine samples.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2014
·
IF 3.107
Jingqing Wu,Ying Ge,Weidong Qin
A method was developed for determining free fatty acids in edible plant oils by incorporation of running-buffer-mediated liquid–liquid extraction and polyamidoamine-dendrimer-assisted capillary electrophoresis–capacitively coupled contactless conductivity detection. The recoveries for the extraction were in the range of 90.1% and 110.3%. Addition of dendrimer to the running buffer improved the separation of fatty acids. Under the optimized buffer conditions, i.e., 3 mM pelargonic acid, 39 mM tris(hydroxymethyl)aminomethane, 30 mM polyoxyethylene 23 lauryl ether, 35% acetonitrile, 15% 2-propanol, 2.5% 1-octanol, and 300 μM polyamidoamine generation 2 at apparent pH 8.53, the 10 model fatty acids were separated in 18 min with detection limits ranging from 0.46 to 3.28 μM. The successful determination of fatty acids in real samples suggests that the method is simple, cost-effective, and easy to operate and is suitable for scanning free fatty acid in edible plant oils.
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高影响因子
Analytical Methods
·
2013
·Vol. 5
·期 19
·5037-5043
·
IF 1.855
Yingtang Li,Yang Jiao,Yuhong Guo,Yaling Yang
A new and fast microextraction technique termed vortex-assisted supramolecular solvent microextraction (VASUSME) has been developed. The method was based on the microextraction of endocrine disrupting compounds (EDCs), including bisphenol-A (BPA), 2,4-dichlorophenol (2,4-DCP), bisphenol-AF (BPAF) and tetrabromobisphenol-A (TBBPA) in 10 mL sample with 500 μL of a supramolecular solvent (SUPRASs), and then detection by high-performance liquid chromatography (HPLC). In the VASUSME procedure, dispersion of microvolumes of a low density extraction solvent into the aqueous sample is achieved by vortex mixing, a mild emulsification procedure. Under the optimum conditions, the repeatability of the proposed method was found to be good. The relative standard deviations (RSD, n = 5) were 3.98–5.64%. The limits of detection (LOD) were in the range of 0.14–0.32 ng mL−1 and the limits of quantification (LOQ) were in the range of 0.41–1.02 ng mL−1. All correlation coefficients of the calibration curves were higher than 0.998. Recoveries of the EDCs spiked into samples of liquid foods and their packaging materials were in the range of 91% to 105.1%. The VASSUSME method was successfully applied to the analysis of BPA, 2,4-DCP, BPAF and TBBPA in samples of liquid foods and their packaging materials. Moreover, the method is simple, sensitive and environmentally-friendly and consumes much less solvent than traditional methods.
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APPLIED SURFACE SCIENCE
·
2014
·
IF 2.538
Yuanji Gao,Bing Xia,Jie Liu,Lisheng Ding,Bangjing Li,Yan Zhou
This study reported a smart, easy to apply, flexible and green strategy for obtaining a biomimic micro-nanostructures. 1-Mercapto-12-( p -nitrophenoxy) dodecane (MPND) and n -dodecanethiol were used to form low surface energy film on a silver mesodendritic structure coated zinc substrate. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize surface morphology and mesocrystal structures. Noncovalently linked sodium nonanoyloxy benzene sulfonate (NOBS) was used to form “lipid-like bilayers” on the surface, making it possible for the surface to switch its surface wettability reversibly. The water contact angle (CA) on the constructed surface varies from 168 ± 2° (before processed by NOBS) to 55 ± 2° (after processed by NOBS). This phenomenon can be explained by the formation and disruption of “lipid-like bilayers” to affect the wettability of the surface. This work is of great scientific interests and may provide insights into the design of novel functional devices that are relevant to surface wettability, such as microfluidic devices and sensors.
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FOOD CHEMISTRY
·
2014
·
IF 3.259
Peijin Wang,Yu Xiao,Wenjun Liu,Juan Wang,Yaling Yang
A rapid, simple, sensitive and environmentally friendly method has been developed for the determination of three oestrogens (17β-estradiol (17β-E2), estrone (E1), and diethylstilbestrol (DES)) in milk samples by using vortex-assisted hollow fibre liquid-phase microextraction (VA-HF-LPME) and high performance liquid chromatography. Method is based on the microextraction of oestrogens from sample solution into 15 μL of nonanoic acid as extracting agent, which is placed inside the hollow fibre followed by vortex-mixing. Vortex provided effective and mild mixing of sample solution and increased the contact between analytes and boundary layers of the hollow fibre, thereby enhancing mass transfer rate and leading to high recovery of target analytes. The extraction equilibrium is achieved within 2 min. Parameters influencing the recovery were investigated and optimized. The proposed technique provided good linearity (>0.9984), repeatability (RSD = 2.56–4.38), low limits of detection (0.06–0.17 ng mL −1 ), and high enrichment factor (330).
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NEW JOURNAL OF CHEMISTRY
·
2013
·Vol. 38
·期 1
·448-454
·
IF 2.966
Lai-Jun Zhang,Xing-Can Shen,Hong Liang,Fa-Yun Chen,Hai-Jin Huang
ZnSe:Mn and core–shell ZnSe:Mn/ZnS doped quantum dots (d-dots) have been synthesized by using the alkylamine–H2Se complex and thiourea as new phosphine-free Se and S precursors, respectively. Absorption spectroscopy, steady-state (solution and solid-state) and time-resolved photoluminescence spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy were used to characterize the resulting d-dots. Results showed that Mn2+ was successfully doped and mainly distributed in the middle layer of the actual ZnSe/ZnSe:Mn/ZnSe d-dots and ZnSe/ZnSeS:Mn/ZnS d-dots which were simply referred to as ZnSe:Mn and core–shell ZnSe:Mn/ZnS d-dots with ZnSe and ZnS outmost shells, respectively. The increase in the intensity of phosphorescence from the dopant Mn2+ was obtained by the corresponding injection of Zn precursor or Zn/S precursors for ZnSe or ZnS shell growth. As compared to the ZnSe shell, the ZnS shell was grown more significantly on the surface of the ZnSe:Mn core, which led to larger d-dots due to a thicker ZnS shell and thus deeper doping of Mn2+ in the larger host. Outstanding improvement has been achieved in both phosphorescence intensity and stability after growth of the ZnS shell relative to the ZnSe shell. The corresponding phosphorescence efficiency of the resulting d-dot cyclohexane solution was enhanced from about 8% for the ZnSe:Mn d-dots to 35% for the ZnSe:Mn/ZnS d-dots.
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SPECTROSCOPY LETTERS
·
2014
·
IF 0.718
Fang Yu,Chang Liu,Yuhong Guo,Yaling Yang
A simple and fast extraction termed vortex-assisted liquid–liquid microrextraction coupled with molecular fluorescence spectroscopy has been developed and used for the detection of three sulfonamides (sulfadiazine sodium, sulfamethoxazole, and sulfaguanidine) in the meat samples. In the vortex-assisted liquid–liquid microrextraction method, 400 µL of nonanoic acid was used as extractant and directly injected into 10 mL centrifuge tube containing a derivative, which sulfonamides derived with o-phthaladehyde. And the extraction solvent was dispersed into the water phase under mechanical force with the vortex-mix. The polar side was reduced and the strong fluorescence produced at λex = 295 nm. Variable parameters affecting the derivatization and vortex-assisted liquid–liquid microrextraction procedure were evaluated and optimized. The vortex-mix substituted effect of disperser solvent in this procedure. The limits of detection were 2.0 ng mL−1 for sulfadiazine sodium and sulfamethoxazole, 0.5 ng mL−1 for sulfaguanidine with the relative standard deviations of the method ranging from 2.5% to 6.1%. And the calibration graph was linear from 5 to 5000 ng mL−1 with coefficient of determinations more than 0.9995. Recoveries of the three sulfonamides on spiked meat samples at different levels were 92.2–102.5%. Finally, the method has been successfully applied to the determination of sulfonamides from meat samples.
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INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2017
·Vol. 41
·期 15
·2555-2564
·
IF 2.598
Zhao Wang,Shang Liu,Guixiang Ma,Shaolei Xie,Guangwei Du,Jinhe Sun,Yongzhong Jia
Summary To satisfy the application demands for latent heat storage in the temperature range from 5°C to 15°C, an original composite phase change material (PCM), CA-NA/EG (caprylic-nonanoic acid/expanded graphite), was prepared and characterized. For CA-NA/EG, the mass ratio of CA and NA was 8:2, and the mass percentage of the CA-NA in CA-NA/EG composite PCM was determined as 90% by leakage test. The melting and freezing points of the CA-NA/EG were 6.84°C and 9.34°C, and corresponding latent heats were 108.75 kJ/kg and 107.67 kJ/kg. In addition, its thermal conductivity, thermal stability and reliability were investigated by thermal conductivity apparatus (TCA), thermal gravimetric analyzer (TGA), and accelerated thermal cycle test for 100 melt/freeze cycles, respectively. The results showed that the CA-NA/EG had a good thermal stability and an excellent thermal reliability. Moreover, the thermal conductivity of CA-NA/EG had an improvement of 25% than that of the CA-NA. On the other hand, the accelerated thermal cycle test also indicated that the CA-NA/EG had no supercooling during all melt/freeze cycles. Therefore, the prepared composite PCM, CA-NA/EG, can be applied for low-temperature thermal energy storage owing to its proper melting temperature, acceptable latent heat and thermal conductivity, excellent thermal stability and reliability.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 3.7
Qian Mao,Changliu He,Biqiang Chen,Xu Zhang
Biolubricants produced by chemically modifying vegetable oils are promising to replace mineral-based lubricants. However, the performances of biolubricants synthesized through traditional chemical modification routes, such as transesterification/esterification, epoxidation with further ring opening, and estolide formation, cannot satisfy the demands of extreme conditions. Meanwhile, complicated multi-step reactions cause expensive costs, which hinders their large-scale application. In this study, pelargonic acid (PA) derived from the cleavage of oleic acid was esterified with trimethylolpropane (TMP) to produce branched-chain esters (tri-TMP esters) catalyzed by the lipase ( Candida sp. 99–125 ), focusing on batch stability of the lipase, thermal-oxidation stability and lubrication performance of the product. The lipase maintained high activity for 4 continuous batches in 5 L enzyme reactor with the conversion of PA > 96% and the accumulation of tri-TMP esters > 84% in each batch. The obtained tri-TMP esters had a pour point of − 56 °C, a viscosity index of 137, and a flash point of 276 °C. Anti-oxidation stability test and thermogravimetric behaviors showed that the biolubricant had favorable thermal-oxidative stability. Friction tests verified that the product displayed excellent lubrication performance with a minimum coefficient of friction (COF) of 0.099 and an average wear spot diameter (WSD) of 221.5 µm. The green and high-selective synthetic pathway fills the defect of existing routes for the preparation of biolubricants from chemically modified vegetable oils.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Qiaowen Zheng,Yanmei Zhou,Jiarong Huang,Heng Lu,Shaoru Wu,Junying Zhang,Yishan Li,Wenping Hong,Xiaohong Tan,Jinming Lin,Qiang Chen,Feiming Li,Zhixiong Cai,Maosheng Zhang
Cu-based perovskite nanocrystals (NCs) have received great interest as alternatives to lead-based perovskite NCs due to their unique advantages of resource abundance and being environmentally friendly. However, the issue of their inherent low luminous efficiency has limited the application of fluorescence sensing fields. In this work, a highly sensitive fluorescence sensor based on Cu-based perovskite NCs has been constructed by embedding Cs 3 Cu 2 I 5 NCs in room temperature curable deep eutectic solvents (Cs 3 Cu 2 I 5 -DES) for the detection of NH 3 gas in the atmosphere. In this strategy, Lauric acid-based DES with room temperature curable property were successfully synthesized and used as the supporting materials of Cs 3 Cu 2 I 5 -DES sensing film. When NH 3 gas exists, NH 3 can be adsorbed and enriched on the surface of Cs 3 Cu 2 I 5 -DES film, and react with the carboxyl group on the DES, which leads to a significant decrease in the fluorescence intensity of Cs 3 Cu 2 I 5 -DES film. Under optimized experimental conditions, the as-prepared sensing film demonstrated a good linear relationship between the decreased intensity of the fluorescence and the NH 3 concentration, and a low limit-of-detection (LOD) of 0.0642 ppm for NH 3 . Furthermore, the sensor also exhibited excellent selectivity and good stability.
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