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排序方式: 共有265条查询结果,搜索用时 15 毫秒
1.
Anham Zafar Dr. Imtiaz-ud-Din Dr. Robert G. Palgrave Dr. Haji Muhammad Dr. Sammer Yousuf Tim Evans 《ChemistryOpen》2023,12(1):e202200229
A series of imidazolium-based symmetrical and asymmetrical dicationic ionic liquids (DcILs) with alkyl spacers of different length and with [FeCl3Br]− as counter ion have been synthesized. The synthesized DcILs are characterized by using FTIR and Raman spectroscopy as well as mass spectrometry, along with single-crystal XRD analysis. Physicochemical properties such as solubility, thermal stability and magnetic susceptibility are also measured. These compounds show low melting points, good solubility in water and organic solvents, thermal stability, and paramagnetism. The products of molar susceptibility and temperature (χmol⋅T) for the synthesized DcILs have been found between 4.05 to 4.79 emu mol−1 K Oe−1 and effective magnetic moment values have also been determined to be compared to that expected from the spin-only approximation. 相似文献
2.
Reversed‐phase vortex‐assisted liquid–liquid microextraction: A new sample preparation method for the determination of amygdalin in oil and kernel samples 下载免费PDF全文
Mohammad Hosseini Rouhollah Heydari Mohammad Alimoradi 《Journal of separation science》2015,38(4):663-669
A novel, simple, and rapid reversed‐phase vortex‐assisted liquid–liquid microextraction coupled with high‐performance liquid chromatography has been introduced for the extraction, clean‐up, and preconcentration of amygdalin in oil and kernel samples. In this technique, deionized water was used as the extracting solvent. Unlike the reversed‐phase dispersive liquid–liquid microextraction, dispersive solvent was eliminated in the proposed method. Various parameters that affected the extraction efficiency, such as extracting solvent volume and its pH, vortex, and centrifuging times were evaluated and optimized. The calibration curve shows good linearity (r2 = 0.9955) and precision (RSD < 5.2%) in the range of 0.07–20 μg/mL. The limit of detection and limit of quantitation were 0.02 and 0.07 μg/mL, respectively. The recoveries were in the range of 96.0–102.0% with relative standard deviation values ranging from 4.0 to 5.1%. Unlike the conventional extraction methods for plant extracts, no evaporative and re‐solubilizing operations were needed in the proposed technique. 相似文献
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Sharifkhani Samira M. Yaftian Mohammad Reza Hosseini Majid Haji Zolfonoun Ehsan 《Journal of Analytical Chemistry》2022,77(4):505-512
Journal of Analytical Chemistry - In this study, for the first time, the organic gas steam-liquid extraction by a special hand-made cell was used as a simple and inexpensive preconcentration... 相似文献
5.
Yahui Yan Rahima Abdulla Xiaoyan Liu Shuping Li Haji Akber Aisa 《Journal of separation science》2022,45(13):2148-2160
6.
Two new 24-methyl lanostane triterpenoids,hispindic acids A and B(1 and 2),and a new phenolic compound,hispinine(7),along with nine known compounds(3-6,and 8-12),were isolated from the fruiting bodies of Inonotus hispidus.Their structures were elucidated based on the extensive analysis of spectroscopic data(NMR and HRMS).Hispindic acid A(1) possesses an unusual formyl group at C-30.Compounds 1,3-4,and 8 showed stronger activate abilities of melanogenesis and tyrosinase in B16 melanoma cells than those of positive control,8-methoxypsoralen,at 50 μmol/L 相似文献
7.
Elahe Kazemi Shayessteh Dadfarnia Ali Mohammad Haji Shabani 《Journal of the Iranian Chemical Society》2017,14(9):1935-1944
A novel and efficient sulfadiazine imprinted polymer was synthesized via co-precipitation method and successfully grafted on magnetic multi-walled carbon nanotubes. The synthesized magnetic imprinted polymer was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, thermal analysis and applied as a sorbent for selective magnetic solid-phase extraction of sulfadiazine. The retained sulfadiazine was eluted by 150.0 µL methanol/acetic acid (6:4) solution and quantified by fiber optic linear array spectrophotometry via formation of a detectable azo dye. All parameters affecting the extraction of sulfadiazine were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 2.0–50.0 µg L?1 with a detection limit of 0.56 µg L?1 and enrichment factor of 300.0. The relative standard deviation at 30.0 µg L?1 of sulfadiazine (N = 6) was 2.8 and 4.6% for intra-day and inter-day, respectively. The method was successfully applied to determine sulfadiazine in human urine, honey, milk and environmental water samples. 相似文献
8.
Rouhollah Heydari Mohammad Hosseini Reza Rezaeepour 《Journal of the Iranian Chemical Society》2017,14(8):1691-1698
In this study, a new device for semi-automated salt-assisted liquid–liquid extraction was designed and coupled with high-performance liquid chromatography (HPLC) to determine three aromatic hydrocarbons in aqueous samples. In order to evaluate the performance of the designed device, three aromatic hydrocarbons including 2-naphthol, naphthalene and anthracene were selected as model analytes. Sample solution, extraction solvent and salt solution using separate channels were transferred to a sample holder, respectively. These three components were mixed using a magnetic stirrer. After stirrer stopping, the aqueous and organic phases were separated and organic layer transferred to the injection loop of HPLC system. Optimization process was achieved using response surface methodology by Design-Expert software. A central composite design was used to optimize the main parameters including pH (A), stirrer time (B), organic solvent volume (C) and salt concentration (D). The limit of quantitation for 2-naphthol, naphthalene and anthracene was 15.0, 25.0 and 1.0 ng mL?1, respectively. Under the optimum conditions, obtained recoveries for three analytes were in the range of 76.0–96.2% with relative standard deviation less than 8.2%. The salt-assisted liquid–liquid extraction method using the proposed device has been successfully used for the analysis of real samples containing studied analytes in various matrices. 相似文献
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Majid Haji Hosseini Peyman Asaadi Mohammad Rezaee Mohammad Reza Rezaei Mohammad Reza Pourjavid Masoud Arabieh Ahmad Amrollah Abhari 《Chromatographia》2013,76(23-24):1779-1784
This work proposes a new, rapid and simple homogeneous liquid–liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography–mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4–7 ng mL?1, while the precisions were found to be in the range of 11.08–14.87 (RSD, n = 3). The linearity of the method lay in the range of 10–150 ng mL?1 with the coefficients of correlation (r 2 ) ranging from 0.998 to 0.999. 相似文献