基于核酸适配体信号置换结合循环扩增的液相色谱法检测4种生物胺

生物胺的含量是衡量食品卫生状况和药物纯度的重要标志之一,建立食品药品中生物胺的精准、灵敏检测具有重要的实际意义。该文基于核酸适配体置换生物胺信号源并结合荧光信号循环扩增的策略,建立了一种新型的同时检测鱼肉、猪肉和抗生素中4种生物胺的高效液相色谱法(HPLC)。首先通过两步信号置换,将无荧光信号的目标物转换为有荧光信号的核酸探针;再结合双链特异性核酸酶辅助信号扩增策略,获取大量不同长度和碱基序列的核酸探针;最后借助HPLC平台实现实际样品中多种生物胺信号的精确识别。文章研究了核酸探针的碱基序列和长度对出峰时间和前后顺序的影响,以提高荧光信号的区分度。通过正交实验探讨了柱温、流速和梯度洗脱过程、反应温度、孵化时间等对信号分离的影响,确定最优条件,提高信号的分离效率。该方法对目标物酪胺、组胺、精胺和色胺的检出限分别为0.25、0.21、0.27和0.19 pmol/L,线性范围为1 pmol/L~1 μmol/L。通过对硫酸大庆霉素、鱼肉和猪肉样品中生物胺含量进行检测,研究了该方法检测实际样品的可行性。该方法可精准识别、捕获和分离复杂基质样品中的生物胺组分,能有效提高对目标分析物的选择性,并降低实际样品中的基质干扰,有望为食品药品分析领域提供一种新的思路。     

高效液相色谱在生物医药研究中的应用第七讲生物胺的分离和测定（下）：多胺及有关化合物的分离和测定

§7-6 多胺及有关化合物的分离 多胺是具有两个以上氨基的脂肪族化合物,四种重要的多胺及有关化合物的名称和结构见表1。此类化合物无紫外吸收,又无荧光和电化学活性,检测困难,必须衍生后才能检测,因此多胺的分离方法与其衍生有关。     

基于层层自组装技术构建灵敏度可调的电化学发光传感器检测FLT3EI北大核心CSCD

选择急性髓系白血病的标志性基因FLT3作为目标物,构建了灵敏度可调的双信号放大电化学发光传感体系。采用层层自组装法将预处理的多壁碳纳米管有序组装到电极表面,利用无酶目标催化发夹反应放大传感器的灵敏度,实现FLT3基因的高灵敏、快速、准确检测。通过电化学交流阻抗谱(EIS)对传感器的构建进行跟踪表征,采用电化学发光法(ECL)对不同浓度的FLT3基因进行检测。结果表明,该传感器可通过控制多壁碳纳米管的组装层数调节灵敏度与检出限。当多壁碳纳米管组装层数为6层时,检测FLT3的线性范围为0.5~50 pmol/L,检出限为0.3 pmol/L。更高灵敏度的传感器有望通过组装更多层数的多壁碳纳米管实现。     

多肽抗体免疫富集-质谱法检测肝癌患者血清多肽标志物

血清多肽是癌症诊断信息的重要来源.近年来针对其复杂多样、丰度低、易降解的特点,多种多肽组技术得到快速发展.建立并优化了检测多肽标志物的免疫质谱方法,用于检测血清中的肿瘤多肽标志物.方法的线性范围为1-40 pmol;检出限为0.5 pmol;对5 pmol合成肽 5标准品平行检测3次的相对标准偏差(RSD)为9.5%....     

薄层色谱法检测黄酒生物胺的研究

在传统薄层色谱检测技术的基础上,建立了一种改良的生物胺测定薄层色谱检测方法,并将该方法应用于不同发酵阶段及不同年份黄酒的生物胺检测。结果表明,该方法可以成功定性、定量检测黄酒中的生物胺,酒中主要是酪胺、组胺、亚精胺、尸胺和腐胺,其中组胺含量未超过50 mg/kg,生物胺总量未超过1 000 mg/kg,符合食品中生物胺限量标准。从生物胺的角度,说明黄酒是安全性食品。另外,与高效液相色谱法相比,本方法不但实现了黄酒生物胺的定性、定量分析,且操作简便、费用低,可同时检测多个样品。     

GC-MS法测定头发中多胺的含量

多胺(polyamines)广泛存在于生物体内,主要包括腐胺(putrescine),精脒(spermidine)和精胺(spermine).多胺与细胞增长和癌症密切相关[1].近年来有文献报道,头发中多胺浓度的增加与恶性子宫癌、卵巢癌[2]、老年痴呆症[3]有关.因此,检测头发中的多胺在临床疾病的诊断方面有一定的意义.     

反相高效液相色谱分析生理性多胺

精胺(SP),精(?)(SPD)、尸胺(CA)、腐胺(PU)等生理性多胺,广泛存在于动植物和细菌体内,是某些氨基酸脱羧产生的一类含有两个或两个以上氨基的脂族化合物,具有一定的生理功能。1971年,Russell首次提出尿多胺含量的变化可作为诊断癌瘤和监测癌瘤的指标。此后,不少研究对体液和癌瘤组织中多胺的分析得到类似结果,陆续报道了进行多胺痕量检测的柱层析高压电泳法、薄层层析法、气液色谱/质谱法、高效液相色谱法,多胺自动分析法、自动氨基酸分析法及放射免疫法。     

大环多胺型荧光探针的研究进展

大环多胺作为含有多个氮原子和闭合环状结构的一类电子供体,在构筑荧光探针方面具有独特的优势。代表性的大环多胺如四氮环(cyclen、cyclam和pyclen)和三氮环(tacn)等,它们被广泛用于金属离子、阴离子、生物活性小分子和生物大分子探针的识别基团或功能基团。本文依据检测对象的不同,综述近年来大环多胺在荧光探针的设计、制备及应用方面的优秀成果,并对未来其在荧光检测分析领域的进一步发展进行了展望。     

基于聚苯乙烯微球放大的凝血酶化学发光检测新技术

本文以羧基96孔板为分离载体,核酸适配体作为分子特异性识别元件,聚苯乙烯微球作为放大载体,辣根过氧化物酶为标记物,构建了化学发光（CL）高灵敏度凝血酶检测新技术.实验结果表明：该放大技术不但灵敏度高,且抗干扰能力强,其他蛋白质如IgG、IgM、IgA、IgE、IFN均无明显干扰.聚苯乙烯微球放大体系中凝血酶的线性范围为7.8～250pmol/L,最低检测浓度可达3.9pmol/L;而不放大检测技术的线性范围为0.94～30nmol/L,最低检测浓度为0.46nmol/L,放大体系将检测灵敏度提高100多倍.综合而言,基于适配体识别和聚苯乙烯微球放大的凝血酶CL检测新技术具有通量大、简单快速和灵敏度高的特点,有望在凝血酶高通量检测领域获得应用.     

构建电化学适配体传感器快速检测中药材中的赭曲霉毒素A

利用壳聚糖（CS）、还原氧化石墨烯（rGO）与氮掺杂多壁碳纳米管（N-MWCNTs）合成N-MWCNTs-rGO-CS复合材料,制备修饰电极,结合赭曲霉毒素A(OTA)的特异性适配体,构建高灵敏度电化学生物传感器,并用于中药中OTA的含量测定。在最优条件下,峰电流变化值与OTA浓度对数值的线性响应范围为2.3 pmol/L～2.3 nmol/L,检测限为0.53 pmol/L。应用该方法对中药饮片中OTA的含量进行加标回收实验,回收率在97.6%～103.2%之间。该方法有望用于中药材中OTA污染的快速检测。     

Zeta potentials of polydimethylsiloxane surfaces modified by polybrene of different concentrations

Zeta potential is an important parameter for characterizing the electrokinetic properties of a solid–liquid interface. In this paper, zeta potentials of polydimethylsiloxane surfaces modified by polybrene (PB) solutions of different concentrations in Phosphate buffer solution and pure water were reported. The zeta potentials were measured by an induction current method. The measurements were validated both by a calibration curve based on the data reported in the published papers and by comparing the zeta potential determined by using the Smoluchowski equation and the measured velocity of the electrokinetic motion of particles in a microchannel.     

Optimization of Extraction Conditions for Flavonoid Composition and Antioxidant Activity of Radix Scutellariae

Microwave, ultrasonic, and reflux extraction were compared to provide an optimized method for flavonoids from Radix Scutellariae including the antioxidant activity of the extracts. The antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays. Baicalin, wogonoside, baicalein, wogonin, and oroxylin A were quantified using ultra-high performance liquid chromatography. For microwave extraction, with a ten minutes treatment, the extraction efficiencies of the analytes were higher than treatments by refluxing for 180 minutes and sonication for sixty minutes. In addition, the antioxidant activity of the microwave extracts was slightly higher than the extracts obtained by the other methods. Microwave extraction conditions were further optimized by a single-factor experiment and the optimum conditions were 50 percent ethanol–water (volume by volume), an extraction temperature of 100 degrees celsius, an extraction time of ten minutes, and a sample to solvent ratio of 1:50. This study combines extraction, phytochemistry, and bioactivity to screen the most efficient extraction procedure for flavonoids from Radix Scutellariae.     

Research on aminomethylene derivatives of azoles XV. Synthesis and structure of aminoethylidene and aminomethylene derivatives of 5-imidazolone

Aminomethylene and aminoethylidene derivatives of 5-imidazolone, the structures of which were studied by means of their UV, IR, and PMR spectra, were synthesized. It is shown that they exist in an enamine structure, primarily in the cis form stabilized by an intramolecularhydrogen bond.     

Determination of artemisinin and artemisinic acid by capillary and packed supercritical fluid chromatography

Artemisinin (an antimalarial compound) and its bioprecursor artemisinic acid, present in the plant Atemisia annua L., were analyzed by supercritical fluid chromatography (SFS) using capillary and packed columns, coupled respectively with a flame ionization detector (FID) and an evaporative light scattering detector (ELSD). Both methods were optimized and validated with columns of different polarity in order to separate artemisinin and artemisinic acid. Analytical results were comparable, but the paced SFC-ELSD method was faster. Indeed, artemisinin and artemisinic acid were separated with an aminopropyl silica column in less than 8 minutes instead of about 25 minutes by capillary SFS. Contrary to conventional gas and liquid chromatography coupled to an UV-visible detector, SFS methods determined both compounds directly, without degradation and/or derivatization in the concentration range expected in the plant material. Results obtained on plant extracts by capillary SFS-FID and packed SFS-ELSD were confirmed by GC-MS.     

大长径比有序多孔阳极氧化铝模板的制备及用于镍纳米线阵列

报道一种恒电流二次氧化制备大长径比(>1000)阳极氧化铝(AAO)模板的方法,研究氧化时间和氧化电流密度分别对制备的AAO模板的表面形貌、孔径大小、厚度等的影响.结果表明,AAO模板的表面形貌及厚度n受m氧、厚化度电约流为密2度00及μ氧m、化长时径间比的为影10响0;-当13氧00化的电高流质密量度A为AO8模m板A·.c采m用-2电时化,氧学化沉1积8方h能法在制制备备出的孔A径A为O模15板0-的20孔0中成功制备了Ni纳米线阵列,分别用扫描电镜(SEM)、高分辨透射电镜(HRTEM)、X射线衍射(XRD)和X射线能量散射光谱(EDS)对其进行了表征;结果显示,制备的Ni纳米线排列整齐有序,每根Ni纳米线直径几乎相同,约150nm,长度约为180-200μm,长径比为1200-1300,与AAO模板的参数一致.研究了Ni纳米线阵列的长径比对其磁性能的影响,发现大长径比的Ni纳米线阵列具有明显的磁各向异性,而长径比约为200的Ni纳米线阵列未表现出明显的磁各向异性.本文结果表明,恒电流二次氧化方法能制备大长径比的AAO模板,并能用于制备大长径比的一维纳米材料阵列,可望在制备具有特殊光学、磁学等性能材料方面得到应用.     

绿豆环氧水解酶催化对硝基苯乙烯氧化物的对映归一性水解

利用绿豆环氧水解酶催化(R,S)-对硝基苯乙烯氧化物水解,产物(R)-对硝基苯乙二醇的产率超过常规酶促拆分的极限产率(50%), 表明发生了对映体会聚. 采用绿豆粉剂和粗酶制剂考察了不同条件下的生物催化反应,结果表明,添加吐温-80 作为分散剂对反应有促进作用. 对该酶的固定化进行了初步研究,发现酶经硅藻土吸附固定化后稳定性显著增加. 在克级规模制备实验中,产物的总产率达73.3%;产物经一步重结晶,得到了光学纯度大于99%的(R)-对硝基苯乙二醇.     

Synthesis of Antitumor Lycorines by Intramolecular Diels-Alder Reaction

Pharmacologically interesting lycorines were obtained by a short, efficient method based on an intramolecular Diels-Alder reaction between an alpha-pyrone and an alkyne, followed by loss of CO(2) in a retro Diels-Alder reaction. The cyclization precursors (pyrones 9) were obtained in good yields in two or three steps from the corresponding homophthalic acid or anhydride.     

Preparation and characterization of rosin glycerin ester and its bromide

Rosin glycerin ester and its bromide were prepared from natural renewable rosin, glycerin and liquid bromine which were first subjected to an esterification reaction, followed by an addition reaction. Their structures were characterized by an infrared (IR) spectrum and their thermal resistance was conducted with thermal gravity (TG) and differential scanning calorimetry (DSC). It showed that the bromide in the rosin glycerin ester decomposed faster than the ester; hence it may be used as fire-resistant material.     

Effect of polyborazine additive on thermolysis of polyphenylsilane and polyvinylsilane

To improve the ceramic residue yields and processabilities of polyphenylsilane (PPS) and polyvinylsilane (PVS), polyborazine (PBN) was employed as an additive. The ceramic residue yield of PPS increased from an original 39wt% to 65wt%, and of PVS from an original 26wt% to 64wt% by simply heating with 1wt% PBN at 70 °C. Furthermore, low viscous PPS and PVS were transformed into highly viscous polymers, which were found to be suitable for hand drawing into green fibers. The enhanced properties were attributed to an increased molecular weight, as analyzed by GPC. ¹H-NMR and ²⁹Si-NMR spectra suggested that dehydrocoupling of SiH₃ in PVS and SiH in PPS by PBN was responsible for the improved ceramic yields.     

Electrochemical synthesis of gallium nanowires and macroporous structures in an ionic liquid

The electrochemical synthesis of gallium nanostructures in an ionic liquid is presented. Gallium nanowires and macroporous structures were synthesized by the template-assisted electrodeposition in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py(1,4)]TFSA) containing GaCl(3) as the precursor. Track-etched polycarbonate membranes with an average pore diameter of 90 nm and a thickness of 21 μm were used as templates for the nanowire synthesis. Ga nanowires with a length of more than 4 μm and an average diameter corresponding to that of the template's pores were easily obtained by this method. Macroporous structures with an average pore diameter of 600 nm were obtained by the electrochemical deposition of Ga inside polystyrene colloidal crystal templates and the subsequent removal of the template by THF. The macroporous deposit showed a granular morphology with smallest grain sizes of about 40 nm and light reflections. The nanostructures of Ga were characterized by HR-SEM and EDX analysis.