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排序方式: 共有164条查询结果,搜索用时 15 毫秒
81.
Junhui Chen Liyuan Gao Zhaoyong Li Shuai Wang Jingxi Li Wei Cao Chengjun Sun Li Zheng Xiaoru Wang 《Analytica chimica acta》2016
The presence of toxins in harmful algal blooms (HABs) poses considerable concerns because of their potential adverse effects on ecological environments and human health. When marine HABs occur, efficient screening and identification of toxins in different kinds of HAB algae remains a challenge. In this study, the applicability of serial coupling of reversed-phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC) combined with high resolution mass spectrometry (HR-MS) for the simultaneous screening and identification of various kinds of known lipophilic and hydrophilic toxins in HAB algae was investigated for the first time. Ultrasound-assisted extraction (UAE) was explored to extract both lipophilic and hydrophilic toxins in algae simultaneously. As in most cases, toxin standards were not available; therefore, an identification procedure based on accurate mass data and chromatographic behavior was proposed. According to this procedure, eight known lipophilic toxins and 11 hydrophilic toxins were successfully detected in a single injection, and the proposed method was validated. Satisfactory sensitivity, repeatability (RSD <14.87%) and recovery (89.4–105.8%) of the method were achieved. A major advantage of the proposed method is that it can almost detect members of all eight groups of marine algal toxins in a single run. Using this method, several known toxins in different marine toxigenic algae including Alexandrium tamarense, Alexandrium minutum and Prorocentrum lima were successfully observed and identified. This work demonstrates that RPLC/HILIC-HR-MS combined with an accurate mass list of known marine algal toxins may be used as a powerful tool for screening of different classes of known toxins in marine harmful algae. 相似文献
82.
糖簇分子和糖树状分子及其生物学活性 总被引:2,自引:0,他引:2
糖簇分子和糖树状分子是近年来发展起来的一类新型糖缀合物,其目的是模拟天然存在的“多元效应”。本文主要综述了目前已知糖簇分子和糖树状分子所具有的生物活性及其潜在的应用领域。 相似文献
83.
84.
Yang B Gu K Sun X Huang H Ding Y Wang F Zhou G Huang LL 《Chemical communications (Cambridge, England)》2010,46(43):8288-8290
A general method is described to analyze pathogen DNAs in homogenous solution by a novel Bio-MassCode probe, using a small organic (namely disulfide) "reporter mass" that self-assembled in oligonucleotide-modified gold nanoparticles. With conventional MALDI TOF MS, the assay simultaneously detected DNAs for HIV, HBV, HCV, and TP with extraordinarily high sensitivity in the low attomolar (10(-18) M) range without any other amplification. 相似文献
85.
86.
Junhui Chen Mingyong Xie Zhihong Fu Frank Sen-Chun Lee Xiaoru Wang 《Microchemical Journal》2007,85(2):201-208
A HPLC fingerprinting method based on the distribution and contents of seven major ginsenosides has been developed for the quality evaluation of Panax quinquefolium. L roots cultivated in China, Singapore and Canada. The method is ideally suited for the fingerprinting of P. quinquefolium. L samples or its derived products for sample authentication or quality control, e.g. pharmaceutical stability studies. Different extraction methods have been evaluated and a protocol established to maximize the gensinosides yields in routine operations. Hierarchical clustering analysis of the fingerprints demonstrates that the distribution and contents of ginsenosides in P. quinquefolium. L root vary depending on geographic location; and the quality of Jilin-cultivated P. quinquefolium. L roots is similar in composition to Canada-cultivated ones, which are generally considered among the best quality in P. quinquefolium. L. 相似文献
87.
ICP-AES初级专家系统中的谱线模拟 总被引:2,自引:0,他引:2
本文阐述了ICP-AES初级专家系统中谱线模拟的理论基础,模拟了Ca、Mg和Al在LTE和non-LTE情况下的离子线与原子线,证明在non-LTE条件下,离子线与原子线的强度比增强了,比LTE条件下的结果更接近实际扫描谱图。本研究模拟计算了Ca和Mg离子线的跃迁上能级能量对离子线强度的影响。 相似文献
88.
ICP-AES初级专家系统中的谱线干扰校正的研究 总被引:3,自引:1,他引:2
本工作建立了ICP-AES初级专家系统中的谱线干扰校正模块,并运用于实际光谱干扰校正问题,获得较好的结果 相似文献
89.
90.
Zhao H Chen J Shi Q Li X Zhou W Zhang D Zheng L Cao W Wang X Lee FS 《Journal of separation science》2011,34(19):2594-2601
A new method has been developed based on ultrasound-assisted extraction (UAE) followed by hydrophilic interaction chromatography (HILIC) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) for the simultaneous determination of 16 nucleosides and nucleobases in medicinal extracts of various marine organisms. The separation was achieved on a Venusil HILIC column (250×4.6 mm id, 5 μm) and gradient elution using a solution of acetonitrile and buffer (0.20% formic acid and 20 mmol/L ammonium acetate) as the mobile phase. Identification of the 16 target nucleosides and nucleobases was based on the retention time, UV spectra, and mass measurements of the protonated molecules ([M+H](+)) and main fragment ions (ESI-TOF/MS). In addition, non-target compounds of 2'-deoxyinosine and four other amino acids were also tentatively identified by ESI-TOF/MS. The 16 target compounds were quantified by HILIC-ESI-TOF/MS under optimized mass conditions. All calibration curves showed good linearity (r(2)>0.9951). The recoveries were 84.72-124.10%, and the limits of detection of the 16 target compounds were 0.6-130.0 ng/mL. The developed method was applied to quantify the target compounds in 15 batches of various marine organisms. The method has potential applicability for the identification and determination of highly polar and low-concentration active compounds in marine organisms. 相似文献