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991.
QING XiangDong WU HaiLong NIE ChongChong LI Yong YAN XiuFang ZHANG XiHua YIN XiaoLi YU RuQin 《中国科学:化学(英文版)》2013,56(11):1641-1650
This work presents a novel application of second-order calibration based on self-weighted alternating trilinear decomposition(SWATLD)algorithm for analyzing the HPLC-DAD data.The proposed method makes it possible to simultaneously determine teflubenzuron,hexaflumuron,flufenoxuron,chlorfluazuron,diflubenzuron and benzoylurea in different fruit samples,i.e.pear,apple and banana,in the selected time region of chromatogram.The concentration,elution time and spectral information of these benzoylurea insecticides are selectively extracted from complex matrices even in the presence of unknown interferences.The root-mean-square error of prediction(RMSEP)and figures of merit,including sensitivity(SEN),selectivity(SEL)and limit of detection(LOD)are employed to access the performance of the method.The LODs obtained for these insecticides are within the range 0.017–0.26 ppm in pears,0.039–0.33 ppm in apples,0.041–0.44 ppm in bananas,respectively.Such a chemometrics-based protocol holds great potential to be extended as a promising alternative for more practical applications in food safety and quality monitoring. 相似文献
992.
Xiang Ting Zhang ZuLei Liu HaiQing Yin ZhengZhi Li Lei Liu XiaoMing 《中国科学:化学(英文版)》2013,56(5):567-575
Science China Chemistry - Nanofiber membranes from the composite of cellulose acetate/polyvinylpyrrolidone were prepared using electrospinning technique. After treated with water and alcoholic KOH... 相似文献
993.
A novel series of diaryl urea derivatives bearing sulfonamide moiety have been designed and synthesized.Their in vitro antitumor effect against human cancer cell lines MX-1,A375,HepG2,Ketr3 and HT-29 was screened and evaluated by the standard MTT assay with sorafenib as the positive control.Some of the compounds showed significant inhibitory activity against multiple cell lines compared to sorafenib.In particular,2,6-dimethyl-4-{6-[3-(4-chloro-3-(trifluoromethyl)phenyl)urea]naphthalen-2-yl}sulfonyl morpholine(10d)was found to be the most potent against A375,HepG2 and Ketr3 with IC50values of 0.65–0.97mol/L,which were 5–20-fold more potent than sorafenib.Compound 10d emerged as a valuable lead for further optimization. 相似文献
994.
The methyl pheophorbide-a and methyl pheophorbide-b were used as starting materials and converted to purpurin-18 ester by ring-opening and rearrangement reaction in their exocyclic ring. N-Substituted purpurin-18 imides were obtained from purpurin-18 ester through amidation reaction of six-membered cyclic anhydride. Further chemical modifications along their peripheries were carried out by a variety of common reactions, including electrophilic substitution, Wittig reaction, allomerization and Vilsmeier reaction, to afford the title compounds with long-wavelength absorption. The structures of all new chlorins were characterized by elemental analysis, IR, UV–vis and 1H NMR spectra. 相似文献
995.
Yu‐Long Wang Meng Feng Xian Tao Qing‐Yun Tang Ying‐Zhong Shen 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(1):25-28
The lanthanum(III) complexes tris(3,5‐diphenylpyrazolato‐κ2N,N′)tris(tetrahydrofuran‐κO)lanthanum(III) tetrahydrofuran monosolvate, [La(C15H11N2)3(C4H8O)3]·C4H8O, (I), and tris(3,5‐diphenyl‐1,2,4‐triazolato‐κ2N1,N2)tris(tetrahydrofuran‐κO)lanthanum(III), [La(C14H10N3)3(C4H8O)3], (II), both contain LaIII atoms coordinated by three heterocyclic ligands and three tetrahydrofuran ligands, but their coordination geometries differ. Complex (I) has a mer‐distorted octahedral geometry, while complex (II) has a fac‐distorted configuration. The difference in the coordination geometries and the existence of asymmetric La—N bonding in the two complexes is associated with intramolecular C—H...N/O interactions between the ligands. 相似文献
996.
Ying Fu Yin‐Xia He Hong‐Xia Hou Wen‐Bo Zhu Hu‐Lin Li Chao Wu Fang‐Yan Xian 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(3):282-284
2,2′‐Anhydro‐1‐(3′,5′‐di‐O‐acetyl‐β‐D‐arabinofuranosyl)uracil, C13H14N2O7, was obtained by refluxing 2′,3′‐O‐(methoxymethylene)uridine in acetic anhydride. The structure exhibits a nearly perfect C4′‐endo (4E) conformation. The best four‐atom plane of the five‐membered furanose ring is O—C—C—C, involving the C atoms of the fused five‐membered oxazolidine ring, and the torsion angle is only −0.4 (2)°. The oxazolidine ring is essentially coplanar with the six‐membered uracil ring [r.m.s. deviation = 0.012 (5) Å and dihedral angle = −3.2 (3)°]. The conformation at the exocyclic C—C bond is gauche–trans which is stabilized by various C—H...π and C—O...π interactions. 相似文献
997.
Chunmei Zhang Zhijia Liu Yongming Li Qi Li Chaojun Song Zhuwei Xu Yun Zhang Yusi Zhang Ying Ma Yuanjie Sun Lihua Chen Liang Fang Angang Yang Kun Yang Boquan Jin 《Analytica chimica acta》2013
In this study, detection of staphylococcal enterotoxin A (SEA) in multi-matrices using a highly sensitive and specific microplate chemiluminescence enzyme immunoassay (CLEIA) has been established. A pair of monoclonal antibodies (mAbs) was selected from 37 anti-SEA mAbs by pairwise analysis, and the experimental conditions of the CLEIA were optimized. This CLEIA exhibited high performance with a wide dynamic range from 6.4 pg mL−1 to 1600 pg mL−1, and the measured low limit of detection (LOD) was 3.2 pg mL−1. No cross-reactivity was observed when this method was applied to test SEB, SEC1, and SED. It has also been successfully applied for analyzing SEA in a variety of environmental, biological, and clinical matrices, such as sewage, tap water, river water, roast beef, peanut butter, cured ham, 10% nonfat dry milk, milk, orange juice, human urine, and serum. Thus, the highly sensitive and SEA-specific CLEIA should make it attractive for quantifying SEA in public health and diagnosis in near future. 相似文献
998.
Zhihong Yan Jinbin Yuan Genhua Zhu Ying Zou Chunyan Chen Shaolei Yang Shouzhuo Yao 《Analytica chimica acta》2013
This study reported for the first time the use of cholesterol-functionalized magnetic nanoparticles (Fe3O4@SiO2@Chol) for the determination of polycyclic aromatic hydrocarbons (PAHs) in traditional Chinese medicine samples (TCMs) by high performance liquid chromatography (HPLC) coupled with fluorescence detection. The method was efficient, environmentally friendly, and fast. The solvent consumption of the proposed column is only half of the conventional column but with higher efficiency. Influencing factors, including sorbent amount, desorption solvent, sample volume and extraction time, were investigated in detail. Under the optimum conditions, good linearity (R2 > 0.991) was obtained over the range of 5–400 ng g−1, with limits of detection (LOD) 0.75, 0.50, 1.0, 0.56, 0.60, 0.84 and 0.80 ng g−1 for anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene, respectively. 相似文献
999.
1000.