Food Analytical Methods
·
2015
·Vol. 9
·期 7
·2026-2035
·
IF 1.956
Du Jiaojiao,Gao Ruixia,Mu Hui
Phthalates represent a potential risk for humans, since they are ubiquitous environmental contaminants. Efficient extraction and purification procedures are demanded for the detection of low concentration levels of phthalates. In this work, a novel type of molecularly imprinted polymers coated onto the surface of vinyl functionalized multi-walled carbon nanotubes was synthesized and coupled with gas chromatography–mass spectrometry (GC/MS) for the selective separation and determination of dioctyl phthalate (DOP) in beverage samples. The morphology, structure property, and thermostability of the resultant polymers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The adsorption properties of the prepared polymers were investigated by equilibrium rebinding and competitive experiments. The resultant imprinted nanomaterials exhibited high capacity and favorable selectivity. In addition, the feasibility of the developed method using the obtained imprinted polymers as a solid-phase sorbent coupled with GC/MS for the selective isolation and determination of DOP in different beverage samples was demonstrated. Under optimal conditions, the limit of detection of the proposed method for DOP was 2.3 ng L −1 . DOP spiked at three levels of concentration in beverage samples was extracted and determined through the application of the present method, with recoveries ranging from 88.6 to 93.0 % with relative standard deviations less than 5.6 %.
研究领域:
分析化学
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环境毒理学
·
食品安全
·
分子识别
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材料科学
·
色谱分析
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
·
2019
·
IF 1.267
Yue Yang,Zihui Liu,Hao Chen,Shengqing Li
A simple and fast method of low-density solvent based dispersive liquid-liquid microextraction (LDS-DLLME) followed by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been developed for the speciation analysis of organoarsenic and inorganic arsenic in water samples. The low-density solvent (octanol) was given as the organic phase and injected into the aqueous sample (donor phase) with methanol as the disperser. With As (V), As (III), p-APAA, 4-HPAA, ROX and PAA as target species, factors of LDS-DLLME including pH value, anionic carriers, elution conditions and extractant, were studied in detail. Besides, volumes of solvents were further optimised by response surface methodology. Under the optimal conditions, the limits of detection for four phenylarsenics and arsenate were in the range of 0.001–0.039 μg L−1. The relative standard deviations (RSDs) were 3.6–9.4% and the enrichment factors varied from 6.2 to 70.8. The proposed method of LDS-DLLME-HPLC-ICP-MS was satisfactorily applied to the determination of six arsenic compounds in water samples with recoveries of 81.8–111.7% for the spiked lake water samples.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Zhi-Hao Jin,Jin-Tao Chen,Wang Li,Shu-Bao Song,Jiu-Zhong Yang,Zhen-Yu Tian
Owing to significant advantages over traditional biofuels, 2-methylfuran (MF) has arisen extensive interest as next generation biofuels . Atmospheric pressure pyrolysis of a 1:1 blend of MF with a three-component (3C) surrogate jet fuel was conducted in a flow tube using synchrotronphotoionization and molecular beam mass spectrometry techniques within a temperature range of 898–1223 K. Therein, the 3C surrogate fuel consists of 66.2% n-dodecane (NC 12 H 26 ), 18.0% 1,3,5-trimethylcyclohexane (T135MCH) and 15.8% n-propylbenzene (NPB, A1C 3 H 7 ). The detailed kinetic model including 579 species and 3474 reactions was developed via validating against both measured and literature data with reasonable agreement. MF exhibits no obvious influence on the 3C components pyrolysis . However, 3C mixtures play an important roles in MF decomposition: lower initial temperature and different decomposition pathways. In the meantime, n-propylbenzene (NPB) pyrolysis curve in 3C and 3C+MF significantly transfers to low temperature zone after 1000 K in contrast to pure NPB, while smaller change was found in the decomposition curve of n-dodecane. Compared with 3C pyrolysis, 3C+MF blends have less formation of aromatic species and light hydrocarbons except for vinylacetylene (C 4 H 4 ) and acetylene (C 2 H 2 ). Allyl radical (C 3 H 3 ) has significant roles in benzene ring formation. The combination of allyl radical with propargyl radical producing benzene and H radical (aC 3 H 5 + C 3 H 3 = A1 + 2H) has the highest contribution to the benzene formation in both 3C and 3C+MF. Moreover, most of naphthalene (A2) formation is also related to C 3 H 3 radical via reaction: A1CH 2 + C 3 H 3 = A2 + H, rather than via HACA (hydrogen abstraction carbon addition) reaction. Interaction of fuel blends was mainly presented through the common and important sensitive reactions which are much to do with CH 3 and H radicals. The overview of product distribution was investigated by providing comparisons of carbon conversion rates during the pyrolysis of 3C and 3C+MF. These results will be helpful to better understand the pyrolysis properties of MF/jet fuel surrogate blends and could contribute to developing new generation biofuels for aviation.
研究领域:
燃料化学
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燃烧动力学
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生物燃料
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能源化学
·
反应机理
·
质谱分析
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2018
·Vol. 37
·期 1
·565-573
·
IF 5.336
Xiaoyuan Zhang,Yuyang Li,Chuangchuang Cao,Jiabiao Zou,Yan Zhang,Wei Li,Tianyu Li,Jiuzhong Yang,Philippe Dagaut
The kinetics of propanal oxidation was studied in a jet-stirred reactor (JSR) at atmospheric pressure. The investigated temperature range is from 450 to 800 K at two different equivalence ratios (0.35 and 4.0). Thanks to the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), critical intermediates were identified, including methylperoxy, methyl hydroperoxide , ethylperoxy, ethyl hydroperoxide, α-lactone, β-propiolactone and ketohydroperoxides. A kinetic model for propanal oxidation was also developed and validated against the present experimental results, as well as those available from the literature. Main chain-branching pathways under the investigated conditions were analyzed based on present experimental data and kinetic model . The O 2 addition reaction to the propanoyl radical and subsequent oxidation reactions play an important role in determining the oxidation rate of propanal under fuel-lean conditions, especially in the low-temperature oxidation region. Under fuel-rich conditions, the decomposition of the propanoyl radical is predominant and C 2 H 5 relevant reactions consequently determine the kinetics of oxidation of propanal.
研究领域:
物理化学
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燃烧化学
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反应动力学
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分析化学
·
能源化学
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DOI
高影响因子
CHROMATOGRAPHIA
·
2018
·Vol. 82
·期 3
·683-693
·
IF 1.401
Shen Chen,Wu Tong,Zang Xiaohuan
In this work, a zeolitic imidazolate framework-based graphene oxide composite (ZIF-8@GO) was prepared and used as the adsorbent in hollow fiber stir bar sorptive extraction. The stir bar was constructed of a small section of hollow fiber filled with 5 mg ZIF-8@GO and a thin stainless wire of 1.5 cm long in its lumen, and used to extract the trace levels of phthalate esters from children’s food samples prior to gas chromatography–mass spectrometric detection. The ZIF-8@GO showed a high adsorption efficiency for the compounds containing aromatic rings. The main experimental parameters that can impact the extraction efficiency including extraction temperature, extraction time, stirring rate, sample salinity, and desorption conditions were investigated. Under the optimized conditions, the limits of detection (LODs) for the five phthalate esters (diethyl phthalate, dipropyl phthalate, diisobutyl phthalate, butylbenzyl phthalate, and di(2-ethylhexyl) phthalate) were 0.15–0.6 µg L −1 for CiCi beverage and pear juice samples, and 0.75–2.2 µg kg −1 for jam samples. The limits of quantitation (LOQs) were 0.5–2.0 µg L −1 for CiCi beverage and pear juice samples, and 2.5–7.5 µg kg −1 for jam samples. Wide linear ranges of 0.5–500.0 µg L −1 and 2.5–2000 µg kg −1 were obtained for CiCi beverage, pear juice samples and jam samples, respectively, with good repeatability (RSD < 11%) and high method recoveries (72%–100%). The lifetime test results showed that the ZIF-8@GO-based hollow fiber stir bar can be reused for 120 extraction cycles without a significant loss of extraction efficiency, indicating its high durability and stability. The established method was applied successfully for the determination of the phthalate esters (PAEs) in children’s food samples. Graphical abstract
研究领域:
分析化学
·
食品安全
·
环境毒理学
·
暴露科学
·
食品化学
·
污染物检测
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）