简单低温水浴法合成鳞片状氧化铜/四针状氧化锌晶须复合光催化剂(英文)

以硝酸铜为原料,聚乙二醇(PEG,Mw=400)为稳定剂和模板剂,采用简单的低温水浴合成法成功合成了四针状氧化锌晶须(T-ZnOw)表面负载鳞片状CuO的纳米复合光催化剂,系统研究了复合催化剂样品的晶体结构和形貌,通过荧光发光光谱(PL)和紫外光照射的条件下样品对阳离子污染物(亚甲蓝,MB)和阴离子污染物(甲基橙,MO)的光催化降解效率表征了样品的光催化性能,同时采用ICP-AES详细分析了PEG 400浓度对T-ZnOw表面负载CuO纳米颗粒数量的影响.结果表明,T-ZnOw表面有序地沉积了大量鳞片状CuO纳米颗粒,随着PEG 400浓度增加,T-ZnOw表面沉积的CuO纳米片数量逐渐增多,且CuO纳米片在T-ZnOw表面的排列更加有序.同时,PEG 400浓度的变化对合成样品特征发光峰的强度也有一定影响,当PEG 400浓度小于0.60 mol/L时,合成样品特征发光峰强度随着PEG 400浓度增大而减小;当PEG 400浓度大于0.60 mol/L时,样品的特征发光峰强度随之有所增加.在紫外光照射条件下,CuO/T-ZnOw纳米复合催化剂样品对MB和MO水溶液的降解均表现出优异的光催化活性,当PEG 400浓度≤0.60 mol/L时,样品的光催化活性随着PEG 400浓度的增大而增加;而当PEG 400浓度大于0.60 mol/L时,样品的光催化活性反而有所降低.此外,在相同条件下,所有样品对MB水溶液的降解效率明显高于对MO水溶液的降解效率.     

Er3+/Yb3+共掺杂SrF2纳米晶的合成及上转换发光特性

利用水热法以聚乙二醇作为分散剂合成了Er3+和Yb3+共掺的SrF2纳米晶.在980 nm半导体激光器激发下.研究了不同Er3+离子掺杂浓度对发光性能的影响,确定了最佳掺杂浓度比,讨论了退火温度对样品发光的影响及样品的协作敏化和声子辅助共振能量传递的上转换发光机制.用X射线衍射和透射电镜对样品的结构和粒度进行了分析.研究结果表明:用水热法在180℃保温13 h下,合成的样品粒径约为50 nm;当CYb3+CEr3+=4:1,而对Er3+掺杂浓度为1.3mol%时,样品上转换发光强度达到最强.     

用高场非对称波形离子迁移谱技术快速检测二乙醇胺

采用高场非对称波形离子迁移谱(FAIMS)对二乙醇胺(DEA)进行快速检测分析, 以热解析法进样, 确定了二乙醇胺的离子特征信号, 并与气相色谱-质谱联用仪的检测结果进行了比较. 用聚四氟乙烯(PTFE)扩散管进样, 控制二乙醇胺样品气(DEA与空气的混合气)浓度, 利用FAIMS对不同浓度的二乙醇胺样品气进行检测. 通过对离子特征信号进行量化和重复性分析, 确定了二乙醇胺样品气的检出限为0.02 μg/L, 并建立了FAIMS检测二乙醇胺样品气的离子电流强度积分面积与样品气浓度关系曲线. 为FAIMS应用于现场快速检测二乙醇胺提供了一定的依据.     

纳米Eu0.10Y1.90-xNdxO3-δ的光致发光特性及浓度猝灭研究

使用超声波作用下的均匀沉淀法,制备了Eu0.10Y1.90-xNdxO3-δ纳米晶荧光粉,用X射线粉末衍射、荧光光谱等对其进行表征.研究了掺杂Nd3 离子对Y2O3∶Eu3 晶格常数、晶粒尺寸及室温光致发光特性的影响.由不同掺杂浓度x=0~0.18下样品的发射光谱强度变化曲线得到猝灭浓度值,探讨了掺杂Nd3 的样品荧光浓度猝灭的机理.发光强度与浓度的关系表明,掺杂离子之间存在的Eu3 -Nd3 或Nd3 -Nd3 间交换相互作用,是导致掺杂样品浓度猝灭的主要原因.     

标准加入-原子荧光光谱法测定罐头中的痕量锡

用微波消解处理样品,采用标准加入-原子荧光光谱法测定罐头中的锡.通过实验探讨了样品预处理条件、仪器条件、微波消解程序、还原剂浓度等对锡测定的影响.锡浓度(X)在1～100 μg/L范围内与荧光强度(Y)呈线性关系,线性方程为Y=50.15X+12.13,相关系数r=0.9995.用该法对水果和蔬菜罐头样品进行了测定,并...     

氢化物原子荧光法测定化妆品中的汞

采用微波消解技术对化妆品样品进行消解,用氢化物原子荧光法测定样品中的汞.改变仪器条件及溶液浓度进行试验,确定最佳试验参数.汞浓度在0～20μg/L范围内与原子荧光强度呈良好的线性关系,相关系数为0.9997,方法检出限为0.0005μg/L.对眼影和润肤露样品进行加标回收试验,回收率为95%～100%.与浸提法相比,微波消解法提取出的汞完全且损失少.     

T形微反应器共沉淀法制备Mg-Al层状双金属氢氧化物及其粒径可控性

采用T形微反应器通过共沉淀法制备了Mg-Al层状双金属氢氧化物(LDHs)纳米颗粒, 考察了流速、混合盐溶液浓度和温度等对产物粒径及其分布的影响. 实验结果表明, 所制备的LDHs样品的形貌和晶体结构与传统共沉淀法结果一致, 但本方法制备的样品粒径小、分布窄. 随着流速增大, 温度升高, 所合成的LDHs样品平均粒径减小, 分布变窄; 而随着混合盐溶液浓度的增大, 所得LDHs样品粒径增大, 分布变宽.     

ESI-MS测定牛血清白蛋白分子量过程中的pH影响

在电喷雾质谱测定牛血清白蛋白分子量的过程中,适当调整样品溶液的酸度,可提高分析测试的灵敏度.在选定最佳样品浓度的基础上,通过适当加入冰醋酸来调整测试样品的pH值,准确测定了标准蛋白质——牛血清白蛋白的分子量.     

利用凝胶渗透色谱示差-紫外检测器联用测定丁苯共聚物的组成分布

将凝胶渗透色谱(GPC)中的示差与紫外检测器联用,测定了无规共聚丁苯橡胶和SBS三元嵌段共聚物中各级分的组成变化.实验方法选择中对比了两种浓度参数的确定方法,发现通过改变注射量来实现浓度变化的方法优于使用系列浓度样品的方法.分别测定标准样品在紫外和示差检测器上信号产生的时间间隔可以确定两个检测器上信号的时间差.根据紫外-示差检测器联用可以看到SBR无规共聚物和三嵌段SBS共聚物样品中每一个级分中随着相对分子质量的变化,苯乙烯含量的变化.     

琼脂糖珠富集β-actin蛋白实验条件的优化

研究不同反应条件(样品初始浓度、温度、时间)下,protein A+G agarose对小鼠脑组织中β-actin蛋白富集的影响.结果在样品初始浓度为0.5g/L,4℃条件下偶联反应2h,Protein A+G agarose对小鼠脑组织中β-actin蛋白的富集效果最好、并且稳定性与重现性良好.     

Dual-light source excitation for mode-filtered light detection

The sensitivity of a multi-channel mode-filtered light detection system has been enhanced by using a dual-light source irradiation technique. The detection system was constructed from an annular column consisting of a bare optical fibre inserted into a capillary. Sample was introduced through the gap between the fibre and the capillary. A multi-channel charge-coupled device was set on the side of the capillary at which four detection windows could be simultaneously monitored. The changes in the intensities of the mode-filtered light on exposure to various concentrations of ethanol samples from each detection window were monitored. The theoretical studies on the sensitivity of detection of the detection system using dual-light source irradiation have been described. The sensitivity of detection was enhanced when a dual-light source instead of a single-light source was employed. The working concentration range for ethanol was 0-80% (v/v) ethanol. The limit of detection was determined to be 1% (v/v) ethanol. The proposed method has been successfully applied to the determination of ethanol contents of some wine samples. The results were satisfactory compared with values obtained from a standard reference method.     

基于智能手机定量测定蛋白质的方法研究

利用智能手机完成了蛋白质浓度的检测,确定了用于图像比色的参数,方法适用于有颜色反应的分析物浓度检测。利用该法检测的相关系数大于0. 99,检出限为0. 21 g/L。考察了不同品牌手机的检测效果,结果表明,检测效果与手机硬件的配置无明显关联。考察了该方法的重复性,对单个样本检测时,3种质量浓度样本的相对标准偏差(RSD)分别为2. 0%、4. 6%、11. 9%;对4个样本进行同时检测,RSD分别为2. 2%、3. 8%、3. 5%、11. 5%。考察了亮度、色温、拍摄距离的影响,结果显示,亮度与色温对检测结果无影响,而拍摄距离有影响。手机APP与分光光度计对样本检测结果的相关系数(r2)为0. 969。该方法准确、重复性高、便携、操作方便,可实现多种分析物实时现场的快速检测。     

Integrated pulsed amperometry for the analysis of organic compounds

Integrated pulsed amperometric detection (IPAD) was applied for the detection of organic compounds for flow injection analysis. The pulse waveform used in the integrated pulsed amperometry consisted of three steps: detection potential, oxidation potential, and adsorption potential. The pulse waveform was applied to the working electrode as the analyte flowed through the electrochemical cell. Unlike ordinary pulsed amperometry, a faradaic current was integrated over the duration period of the detection potential in the IPAD. Therefore, the total charge was measured by integrating the current after the detection potential was applied. The current for the initial 10 ms, after applying the detection potential, was excluded from the integration due to a large charging current at the initial period. Compared with pulsed amperometry, integrated pulsed amperometry provides a better signal-to-noise ratio and a lower detection limit. This method was applied to the quantitative analysis of thiourea as a representative analyte of organosulfur compounds in a flow injection analysis.     

Aptamers-based sandwich assay for silver-enhanced fluorescence multiplex detection

In this work, aptamers-modified silver nanoparticles (AgNPs) were prepared as capture substrate, and fluorescent dyes-modified aptamers were synthesized as detection probes. The sandwich assay was based on dual aptamers, which was aimed to accomplish the highly sensitive detection of single protein and multiplex detection of proteins on one-spot. We found that aptamers-modified AgNPs based microarray was much superior to the aptamer based microarray in fluorescence detection of proteins. The result shows that the detection limit of the sandwich assay using AgNPs probes for thrombin or platelet-derived growth factor-BB (PDGF-BB) is 80 or 8 times lower than that of aptamers used directly. For multiplex detection of proteins, the detection limit was 625 pM for PDGF-BB and 21 pM for thrombin respectively. The sandwich assay based on dual aptamers and AgNPs was sensitive and specific.     

Separation of metalloporphyrins by capillary electrophoresis with UV detection and inductively coupled plasma mass spectrometric detection

Vitamin B12, cobalt protoporphyrin, manganese protoporphyrin, and zinc protoporphyrin were separated using capillary electrophoresis, and a comparison was made between detection with inductively coupled plasma mass spectrometry (ICP-MS) and UV detection. Absolute limits of detection were slightly better with ICP-MS detection than with UV detection, but for both methods absolute detection limits were in the picogram range. The migration times of the analytes decreased by several minutes when ICP MS detection was employed, and this phenomenon was believed to be a result of a "suction effect" that developed when the CE capillary was interfaced to the ICP-MS nebulizer. However, the resolution between species containing the same metal atom was not altered significantly, and the separation was completed in much less time relative to separations performed with UV detection.     

外星推进剂质量检测标准分析

对比分析了国内外卫星推进剂在取样方法、质量检测方法、检测指标等方面所依据标准的差异,分析了我国推进剂检测实验室依据国际标准对外星推进剂进行质量分析的能力,为推进剂检测实验室具备和提高外星推进剂质量分析的能力提出了具体的措施。     

Study of the peak broadening due to detection in the electrophoretic separation of DNA by CE and microchip CE and the application of image sensor for ultra‐small detection cell length

Narrow peaks are important to high‐resolution and high‐speed separation of DNA fragments by capillary electrophoresis and microchip capillary electrophoresis. Detection cell length is one of the broadening factors, which is often ignored in experiments. However, is it always safe to neglect detection cell length under any condition? To answer this question, we investigated the influence of detection cell length by simulation and experiments. A parameter named as detection cell length ratio was proposed to directly compare the detection cell length and the spatial length of sample band. Electrophoretic peaks generated by various detection cell length ratios were analyzed. A simple rule to evaluate the peak broadening due to detection cell length was obtained. The current states of the detection cell length of detection system and their reliabilities in capillary electrophoresis and microchip capillary electrophoresis were analyzed. Microchip capillary electrophoresis detection with an ultra‐small detection cell length of 0.36 μm was easily achieved by using an image sensor.     

Determination of phenolic antioxidants in pharmaceutical formulations by liquid chromatography and migration study on HDPE packagings

Summary The performance of UV diode-array, spectrometric and electrochemical detectors was compared in the chromatographic analysis of trace amounts of six phenolic antioxidants. Quantitative validation was undertaken; the linearity range was wider using UV detection although the limits of detection were lower with electrochemical detection. UV detection was applied both to identification of an antioxidant in a hydrophilic suspension and to a migration study.     

A simple microfluidic chlorine gas sensor based on gas-liquid chemiluminescence of luminol-chlorine system

In this work, a microfluidic chlorine gas sensor based on gas-liquid interface absorption and chemiluminescence detection was described. The liquid chemiluminescence reagent-alkaline luminol solution can be stably sandwiched between two convex halves of a microchannel by surface tension. When chlorine gas was introduced into the micro device, it was dissolved into the interfacial luminol solution and transferred to ClO(-), and simultaneously luminol was excited and chemiluminescence emitted. The emitted chemiluminescence light was perpendicularly detected by a photomultiplier tube on a certain detection region. The remarkable advantage of the detection system is that both adsorption and detection were carried out at the gas-liquid interface, which avoids the appearance of bubbles. The whole analytical cycle including filling CL reagent, sample injection, CL detection and emptying the device was as short as 30 s. The linear concentration range of chlorine gas detection with direct introduction of sample method is from 0.5 to 478 ppm. The detection limit of this method is 0.2 ppm for standard chlorine gas and the relative standard deviation of five determinations of 3.19 ppm spiked chlorine sample was 5.2%.     

Separation of perfluorocarboxylic acids using capillary electrophoresis with UV detection

A capillary electrophoretic method with UV detection for separation and quantitation of perfluorocarboxylic acids (PFCAs) from C6-PFCA to C12-PFCA has been developed. The optimization of measurement conditions included the choice of the most appropriate type and concentration of buffer in the background electrolyte (BGE), as well as the type and the content of an organic modifier. The optimal separation of investigated PFCAs was achieved with 50 mM phosphate buffer and 40% isopropanol in the BGE using direct UV detection. The optimum wavelength for direct UV detection was optimized at 190 nm. For indirect detection, several chromophores were studied. Five mM 3,5-Dinitrobenzoic acid (3,5-DNBA) in 20 mM phosphate buffer BGE and indirect UV detection at 280 nm gave the optimal detection and separation performance for the investigated PFCAs. The possibility of on-line preconcentration of solutes by stacking has been examined for indirect detection. The detection limits (LODs) determined for direct UV detection ranged from 2 microg/mL for C6-PFCA to 33 microg/mL for C12-PFCA. The LODs obtained for indirect UV detection were comparable to those obtained for direct UV detection.