Analytical Methods
·
2020
·Vol. 13
·期 5
·636-641
·
IF 2.596
Beiqi Wu,Zhengyan Guo,Xiuting Li,Xin Huang,Chao Teng,Zhenjia Chen,Xu Jing,Wenting Zhao
This work presents a novel and green analytical procedure involving a deep eutectic solvent-based dispersive liquid–liquid microextraction with solidification of floating organic droplets (DES-DLLME-SFOD) followed by HPLC to measure three pyrethroids (bifenthrin, β-cypermethrin, and deltamethrin) in cereal samples. Firstly, a low-density hydrophobic DES was synthesized from thymol and octanoic acid in the molar ratio of 1/4 and this was applied as a green extraction solvent in the DLLME procedure to avoid the use of a toxic extractant. After centrifugation and placing it on an ice bath, it is transformed into a solid phase on the top of the sample solution to reduce the loss of extractant, conducive to convenient collection thereafter. This procedure required the optimal conditions (including the type, proportion, and amount of DES as the extractant, the volume of the dispersant acetonitrile, the amount of salt, and the pH value) to be evaluated. Under optimized variates, the proposed method provided good linearity with a correlation coefficient greater than 0.997 and limits of quantification within the range of 6.6–8.9 μg kg−1. The recoveries of pyrethroids in corn, wheat, barley, and oats were 75.6–87.2%, and the relative standard deviation was less than 3.6%. The method, therefore, offers a green, efficient, and convenient approach for the determination of pesticides in cereals.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Xu Jing,Huihui Wang,Xin Huang,Zhenjia Chen,Junling Zhu,Xiaowen Wang
This research used a digital image colorimetry (DIC) method to detect carbaryl in food samples using effervescence-assisted liquid phase microextraction based on solidification of switchable hydrophilicity solvent combined with a microfluidic thread-based analytical device (EA-LPME-SSHS-μTAD). 1-naphthol, the hydrolysate of carbaryl, was extracted into octanoic acid by the adjustment of pH values of the sample solution and separated through solidification in an ice bath. Then 1-naphthol contained in the extracted solution was coupled with 4-methoxybenzenediazonlum tetrafluoroborate (MBDF) fixed on the μTAD to produce tangerine compounds. The inherent colour variation was captured by a smartphone and processed to calculate the intensity ( I ). Under the optimal conditions, the limit of quantification was within 0.020–0.027 mg kg −1 . The recovery was varied in the range from 92.3% to 105.9% with a relative standard deviation (RSD) below 5%. The developed method provides an alternative strategy to extract and detect pesticides for food samples.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Liyan Jia,Xin Huang,Wenfei Zhao,Huihui Wang,Xu Jing
In this study, a simple, efficient, and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent (ETA-ME-SDES) was developed to determine picoxystrobin, pyraclostrobin, and trifloxystrobin in water, juice, wine, and vinegar samples by HPLC. An eco-friendly, hydrophobic, deep eutectic solvent (DES, acting as the extraction solvent) was synthesized by thymol and octanoic acid in the molar ratio of 1:5. The extraction solvent dispersed in sample solutions with the assistance of pH adjustment and effervescence reaction, and was collected after solidification in an ice bath. Several essential conditions, including the type and the volume of DESs, the amount of ammonia hydroxide, and the components of effervescence tablets were optimized. The limits of detection ranged from 0.15 to 0.38 μg L −1 . Extraction recovery ranged from 77.4 to 106.9%. The proposed method was successful in determining the amount of strobilurin fungicides in water, juice, wine, and vinegar samples.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Kaige Zhang,Shuangying Li,Yunhe Wang,Jing Fan,Guifen Zhu
For this work, a novel air-assisted liquid-liquid microextraction based on solidification of floating deep eutectic solvent (AA-LLME-SFDES), coupled with a high performance liquid chromatography (HPLC) method was developed for the detection of benzophenone and salicylate ultraviolet filters in water samples. Three types of fatty acid-based hydrophobic deep eutectic solvents (DESs) with low viscosity, low-density, and melting point close to room temperature were prepared and employed as extraction solvents. This air-assisted liquid-liquid microextraction was carried out in a glass centrifuge tube. Subsequently, the glass tube was introduced into ice-water bath and held for 3 min, during which the upper DES phase was solidified. The water phase was easily extracted using a syringe equipped with a long needle, and later, the glass tube was removed from ice-water bath. The solidified DES phase was immediately melted at room temperature and used for HPLC analysis. The response surface methodology was employed to optimize some influencing parameters such as the volume of the extraction solvent, the pH value of sample solution, the number of extraction cycles, and the addition of salt. A quadratic model, namely a central composite design, was used to replace the conventional single factor analysis. It was found that under optimal conditions, the limits of determination and quantification were 0.045–0.54 µg L −1 and 0.15–2.0 µg L −1 , respectively. The relative standard deviations for inter-day ( n = 5) and intra-day ( n = 5) precision were ≤ 4.2%, whereas the enrichment factors for the ultraviolet filters were obtained from 41 to 50. Furthermore, this novel method was successfully employed for the detection of benzophenone and salicylate ultraviolet filters from real water samples. The recoveries ranged from 87.5% to 105.8%, whereas the RSDs were lower than 3.6%.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2019
·
IF 4.527
Dezhi Yang,Yingdong Wang,Jianbo Peng,Chun Xun,Yaling Yang
A simple, effective and convenient method for determination of phenolic compounds by acid-base induced deep eutectic solvents (DESs) microextraction was developed. The binary and ternary DESs were prepared by a range of fatty acids (C 8 -C 12 ), which can act as hydrogen bond donors and hydrogen bond acceptors simultaneously. The gas-assisted mixing customization provides excellent mixing performance and concentration efficiency through the bubble adsorption mechanism for the handling of large-volume aqueous sample. In extraction process, NH 3 ·H 2 O can act as the emulsifier agent and reacted with DESs to form salts with a cloudy solution, which can obviously improve the extraction efficiency. HCl can act as the phase separation agent, and there is no need to centrifuge, which increases the efficiency of analysis procedure. The factors affected on extraction efficiency were carefully optimized. At optimum conditions and molar ratio of C 8 :C 9 :C 12 (3:2:1), the limit of detections (LODs), the preconcentration factor, the repeatability (RSDs%) were in the range of 0.22–0.53 μg L −1 , 235–244, and 2.6–6.7%, respectively. Finally, the proposed method was applied to analyze four phenolic compounds in real water samples and the recoveries were between 87.4% and 106.6%.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Jiaqi Wen,Yunguang Lu,Longyan Shi,Yaling Yang
A fatty acid deep eutectic solvent (DES) based cloud point extraction (DES-CPE) coupled with high-performance liquid chromatography (HPLC) to determine ultraviolet absorbent (UV) in food packaging bags was presented. In this DES-CPE method, DESs prepared from medium-chain saturated fatty acids (C 8 -C 12 ) and menthol are pH-dependent phase, and acid-base reactions can be carried out solely by adjusting the pH of the solution. The reaction conditions and extraction conditions, such as pH value, speed and time of vortex, selection and dosage of the extraction solvent, reaction time and temperature, effects of salt addition and centrifugation time were investigated in detail. Under optimal condition, the proposed method showed good linear range from 1 to 100μgmL −1 , with good assuming regression coefficients ( R 2 ) ≥ 0.997. The limit of detection (LODs), the quantitation (LOQs), the repeatability (RSDs%) were in the range of 0.05–0.17 μgmL −1 , 0.18–0.52 μgmL −1 , 0.93–2.65%, respectively. The enrichment factor was 10 and the recoveries of three Ultraviolet absorbents were between 82.2% and 103.4%.
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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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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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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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JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Wenhua Ji,Xiuli Ma,Jinghua Zhang,Hongkai Xie,Feng Liu,Xiao Wang
In this work, a dummy molecularly imprinted polymers (MIPs) were developed as the selective sorbents for preparation of the high purity gingerols from ginger for the first time. The dummy template molecule with similar structural skeleton to gingerols, N-vanillylnonanamide, has been designed and synthesized. The performance of the MIPs and non-imprinted polymers (NIPs) were evaluated including selective recognition capacity, adsorption isotherm, and adsorption kinetics. Optimization of various parameters affecting dummy molecular imprinted solid phase extraction (MISPE), such as the type and flow rate of the loading solvent, the composition and volume of the eluting solvent, and the composition and volume of the washing solvent were investigated. Gingerols with the percent recovery of 80 and the percent purity of 99.1 were obtained from the extracts of ginger by MISPE. Besides, gingerols obtained by MISPE had more powerful activity of eliminating free radical compared with extracts before extraction with the MISPE column. Application of MIPs with a high affinity toward three gingerols provides a novel method for obtaining a group of compounds which have likely active groups from natural products.
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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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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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