常用食品农药残留快速检测样品前处理技术

在食品农药残留快速检测样品前处理方法中,常用的有固相萃取和微萃取、微波辅助萃取、超临界流体萃取和凝胶渗透色谱技术等。在实际工作中,应根据各种方法的适用范围和优缺点以及待测样品的种类和基质、检测仪器和对结果的要求等,合理选择相应的样品前处理方法,保证检测结果的准确性。     

中药材中残留农药的检测方法

综述了近年来中药材中残留农药的常用检测方法,以及固相微萃取、超临界流体萃取、基质固相分散技术、免疫亲和技术及分子烙印聚合物技术等新的提取净化方法,以及色谱、质谱、免疫技术在中药材残留农药检测中的应用。     

水环境中药物污染分析的研究进展

目的为我国开展水环境中残留药物污染的分析研究和环境生态风险评价提供参考依据。方法以近年来所发表的24篇文献为依据,对当前国内外水环境中残留药物的污染现状、危害和分析检测技术进行综述。结果世界范围内存在严重的水环境残留药物污染问题,对人和动物的健康造成了危害;水环境中残留药物的分析检测方法主要运用固相萃取技术进行样品前处理,并结合液质联用技术进行分析检测。结论水环境中的残留药物作为一种新的环境污染物,已经受到了全世界范围内的关注,我国也应尽快开展这方面的研究。     

农药残留分析的前处理方法

农药残留分析是在复杂的基质中对目标化合物进行鉴别和定量.在农药残留分析中,样品的净化要尽可能的除去与目标物同时存在的杂质,以减少色谱图中的干扰峰,同时避免杂质对色谱柱和检测器的污染,尤其是含杂质较多的样品前处理技术,一直是分析领域中最为活跃的前沿课题之一,现综述几种农残分析的前处理方法,供广大分析 工作者参考.     

中药中农药残留分析前处理技术及其应用

近年来,中药饮片、中成药含有的有害元素和农药残留量引起人们的广泛关注,出口的中药饮片及中成药首先被检测的就是此类成分[1],成为中药出口的瓶颈,尤其是农药残留严重影响了中药的有效性和安全性。目前我国使用的各种农药多达几百种,常用农药至少也有几十种,中药材成分复杂,农药品种繁多[2],农药残留量检测难度大,而前处理技术是其关键,很大程度上决定了分析结果的准确与否[3]。前处理技术主要包括提取和净化两个过程,其目的是将样品中痕量农药从其他干扰物质中分离提取并进行富集,除去干     

中药材中农药残留分析的研究进展

目前中药材的种植和农药的使用是密切相关的,而且大部分农药是很难降解的,由此带来的中药材的农药残留和对环境的污染是亟待解决的问题。建立高效快速的农药残留检测方法是近年来研究的热点,本文综述了目前中药材中农药残留的现状,中药材中农药残留检测方法的研究进展,详细介绍了色谱法,联用技术,以及免疫分析法在农药残留分析中的应用领域以及未来的发展方向。     

中药中农药残留检测方法研究

目的 探讨中药中农药残留的检测方法.方法 分析当前中药中农药残留现状,对中药中农药残留检测前处理技术及检测方法进行阐述分析.结果 色谱法、免疫分析法、联用法在中药中农药残留检测方面均具有不同的优缺点.结论 不同的检测方法给中药中农药残留的快速检测提供了有力的参考.     

液相微萃取技术在生物样品药物检测中的应用

本文详细介绍了一种新型的样品前处理技术——液相微萃取(liquid phase micmextraction,LPME)技术的发展概况和当前国内外所采用的主要萃取模型及其基本原理,讨论了可能影响其萃取效果的实验参数及其优化方法。综述了这种新型样品前处理技术在生物样品药物检测中的应用状况。     

液相微萃取技术及其在生物样品预处理中的应用进展

液相微萃取是在液相萃取技术基础上发展起来的新型生物样品前处理技术,具有简便、快速、经济、环保等特点,已在血液、尿液、唾液等生物基质样品分析中广泛应用。本文通过查阅近5年文献,对液相微萃取技术的主要模式,即单液滴微萃取、分散液-液微萃取和中空纤维液相微萃取的基本原理,以及其在生物样品预处理中的应用进展进行综述,以期为体内药物分析、药代动力学研究以及新药研发等领域样品前处理提供技术支撑和参考。     

中空纤维液相微萃取技术的应用研究

近年来,随着人们对食品和环境安全的重视度不断提高,单纯的检测分析不能对复杂样品中痕量组分进行定量分析,也使传统的样品前处理面临新的挑战,因此,寻求一种高富集、绿色环保、快速净化的样品前处理新技术,已成为目前检测分析研究的热点之一.基于这一问题,提出了中空纤维的液相微萃取(HF-LPME),其具有高浓缩、快速友好的样品前处理功能.本文重点对HF-LPME的模式及原理、仪器装置、影响因素、应用领域以及发展前景作了综述.     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.