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991.
An amperometric artemisinin (ARN) sensor based on the supramolecular recognition of glycosylated metalloporphyrin, which is included in the Au-nanoparticles-chitosan film coated on the glass carbon electrodes, was developed. For the improvement of the selectivity of artemisinin detection, 5,10,15,20-tetrakis[2-(2,3,4,6-tetraacetyl-β-d-glucopyranosyl)-1-O-phenyl]porphyrin (T(o-glu)PPH) metal complex [FeT(o-glu)PPCl] was synthesized and employed as a ARN-sensitive and -selective material in the amperometric sensors. The proposed [FeT(o-glu)PPCl]/Au-nanoparticles modified electrodes showed excellent selectivity and sensitivity toward ARN with respect to a number of interferents and exhibited stable current response, which can be attributed to the coordination of ARN with the [FeT(o-glu)PPCl] in the electrodes. The calibration graph obtained with the proposed sensor was linear over the range of 1.8 × 10−7-1.7 × 10−9 mol l−1, with a detection limit of 1.7 × 10−9 mol l−1 for ARN. Significant advantages of the proposed procedure over the conventional reductive electrochemical methods are the selective detection and the relatively low applied potential requirement of the ARN-sensor. The prepared sensor is applied for the determination of ARN in plant samples and the results agreed with the values obtained by the pharmacopoeia method. 相似文献
992.
Tingbing Cao Jinyu Chen Chaohui Yang Weixiao Cao 《Macromolecular rapid communications》2001,22(3):181-184
Using the self assembly technique, a stable multilayer films was successfully fabricated from diazoresin (DR) and poly(styrene‐co‐(N‐(p‐hydroxyphenyl)maleimide)) (P(S‐co‐HPMI)) followed by UV irradiation. The driving force of the self‐assembly was confirmed to be H‐bonding attraction between the diazonium group (—N2+) of DR and the phenolic hydroxy group (—Ph—OH) of P(S‐co‐HPMI). A linkage conversion from H‐bond to covalent bond takes place after decomposition of the —N2+ group using UV irradiation. As a result, the stability of the film towards polar solvents increases dramatically. 相似文献
993.
Yanyan Kong Xingqin Zhou Guoxian Cao Xijie Xu Meifen Zou Xiaofeng Qin Rongjun Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):93-101
Pyrroloquinoline quinone (PQQ), an essential nutrient, antioxidant, redox modulator and nerve growth factor found in a class
of enzymes called quinoproteins, was labeled with 99mTc by using stannous fluoride (SnF2) method. Radiolabeling qualification, quality control and characterization of 99mTc-PQQ and its biodistribution studies in mice were performed and discussed. Effects of pH values, temperature, time and reducing
agents concentration on the radiolabeling yield were investigated. The quality control procedure of 99mTc-PQQ was determined by thin layer chromatography (TLC), radio high-performance liquid chromatography (RHPLC) and paper electrophoresis
methods. The average radiolabeling yield was 94 ± 1% under optimum conditions of 0.99 mg of PQQ, 30 μg of SnF2, 0.5 mg of ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) and 18.5 MBq of Na99mTcO4 at pH 6 and 25 °C with a response volume of 1 ± 0.1 mL. 99mTc-PQQ was stable and anionic. Lipid–water partition coefficient of 99mTc-PQQ was −1.49 ± 0.16. The pharmacokinetics parameters of 99mTc-PQQ were t
1/2α = 18.16 min, t
1/2β = 100.45 min, K
12 = 0.013 min−1, K
21 = 0.017 min−1, K
e = 0.016 min−1, AUC (area under the curve) = 1040.78 ID% g−1 min and CL (plasma clearance) = 0.096 mL min−1. The dual-exponential equation was Y = 10.88e−0.038t
+ 5.21e−0.0069t
. The biodistribution of 99mTc-PQQ was studied in ICR (Institute for Cancer Research 7701 Burhelme Are., Fox Chase, Philadelphia, PA 1911 USA) mice. In
vitro autoradiographic studies clearly showed that the 99mTc-PQQ radioactivity accumulated predominantly in the hippocampus and cortex, which had a high density of N-methyl-d-aspartate Receptor (NMDAR). The enrichment can be blocked by NMDAR redox modulatory site antagonists-ebselen (EB) and 99mTc-PQQ is therefore a promising candidate for the molecular imaging of NMDAR. To date, however, there have been no studies
characterizing 99mTc-PQQ. 相似文献
994.
995.
996.
室温下,通过双核配合物[Cu(dppm)(NO3)]2(dppm=双二苯基膦甲烷)与四苯基硼钠在甲醇和二氯甲烷混合溶剂中反应制备了三核铜(I)配合物[Cu3(dppm)3(NO3)(OH)](NO3),经过红外光谱、热重分析、核磁和ES-MS等现代分析手段表征了配合物的物理化学性质,并进一步研究了配合物在室温下的荧光光谱特征。 相似文献
997.
2-羟基-5-磺酸基苯基重氮氨基偶氮苯分光光度法测定痕量汞(Ⅱ) 总被引:16,自引:0,他引:16
研究了 2 羟基 5 磺酸基苯基重氮氨基偶氮苯 (HSDAA)与汞 (Ⅱ )的显色反应。在TritonX 10 0存在下 ,于pH 10 30的硼砂 氢氧化钠缓冲溶液中 ,汞 (Ⅱ )与试剂形成 1∶2的稳定橙红色配合物 ,其最大吸收波长位于 5 19nm处 ,表观摩尔吸光系数为 1 6 7× 10 5L·mol- 1 ·cm- 1 。汞 (Ⅱ )在 0~ 6 0 0 μg·L- 1 之间符合朗伯 比尔定律。该法直接应用于水样中痕量汞的测定。 相似文献
998.
The paper advanced the theoretical procedures for quantitative design on selective stacking of zwitterions in full capillary sample matrix by a cathodic-direction moving reaction boundary (MRB) in capillary electrophoresis (CE) under control of electroosmotic flow (EOF). With the procedures, we conducted the theoretical computations on the selective stacking of two test analytes of L-histidine (His) and L-tryptophan (Trp) by the MRB created with 30 mM pH 3.0 formic acid-NaOH buffer and 2-80 mM sodium formate. The results revealed the following three predictions. At first, the MRB cannot stack His and Trp plugs if less than 12.5 mM sodium formate is used to form the MRB and prepare the sample matrix. Second, the MRB can stack His and/or Trp sample plugs completely if higher than 50 mM sodium formate is chosen to form the MRB. Third, the MRB can only focus His plug completely, but stack Trp plug partially if 20-50 mM sodium formate is used; this implied the complete MRB-induced selective stacking to His rather than Trp. All the three predictions were quantitatively proved by the experiments. With great dilution of sample matrix and control of EOF, controllable, simultaneous and MRB-induced selective stacking and separation of zwitterions were achieved. The theoretical results hold evident significances to the quantitative design of selective stacking conditions and the increase of detection sensitivity of zwitterions in CE. In addition, the control of EOF by cetyltrimethylammonium bromide (CTAB) can evidently improve the stacking efficiency to both His and Trp. 相似文献
999.
Bingzhi Li Min Chen Yang Li Xiaolin Cao Yongxin She Jungang Yin Shuang Cong Ziping Zhang 《Journal of separation science》2022,45(3):752-759
In this paper, a flower-like molybdenum disulfide material was prepared by hydrothermal method and was first used as adsorbents in the solid-phase extraction process for enriching N-nitrosoamines. Molybdenum disulfide exhibited three-dimensional petal-like microspheres with about 500 nm in diameter. The relevant analyte extraction and elution parameters (sample volumes, solution pH, washing solvents, elution solvents, and elution volumes) were optimized to improve the solid-phase extraction efficiency. The solid-phase extraction process coupled with high-performance liquid chromatography-tandem mass spectrometry for determining N-nitrosoamines in environmental water samples was established. The limits of detection were in the range of 0.01–0.05 ng/mL. The satisfactory recoveries (68.9–106.1%) were obtained at three different spiked concentrations (2, 5, and 8 ng/mL) in water samples, and the relative standard deviations were between 1.96 and 8.38%. This proposed method not only showed high sensitivity and good reusability but also provided a new adsorbent for enriching trace N-nitrosoamines in environmental water samples. 相似文献
1000.
Wenbin Shu Yitai Xiao Lizhu Wang Mingzhu Liang Zhihong Li Xiangwen Wu Qingdong Cao 《Molecules (Basel, Switzerland)》2022,27(21)
Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies globally. Peptide-based tumor-targeted imaging is critical for ESCC imaging. In this study, we aim to identify a peptide-targeting IGF2BP2 that specifically binds to human ESCC for near-infrared imaging of esophageal cancer. Applying phage display techniques, we identified a peptide target for IGF2BP2 which was confirmed to be highly expressed in ESCC cell lines or tumor tissue and may serve as an imaging target for ESCC. We conjugated the peptide to the NIRF group, Cy5, and further evaluated the targeting efficacy of the probe at a cellular level and in animal tumor models. The Cy5 conjugated peptide (P12-Cy5) showed a high binding affinity to human ESCC cells in vitro. In vivo, optical imaging also validated the tumor-targeting ability of P12-Cy5 in KYSE-30-bearing subcutaneous ESCC tumor models. Furthermore, the results of biodistribution showed a significantly higher fluorescence intensity in tumors compared to scrambled peptide, which is consistent with in vivo observations. In summary, an IGF2BP2-targeted peptide was successfully identified. In vitro and in vivo experiments confirmed that P12-Cy5 has high affinity, specificity and tumor-targeting properties. Thus, P12-Cy5 is a prospective NIR probe for the imaging of ESCC. 相似文献