Key Conditions in Capillary Electrophoresis of Amino Acids with Indirect Ultraviolet Detection

Key factors for capillary electrophoresis of amino acids with indirect ultraviolet detection were illustrated. Buffer compositions and additives were found to be influential as expected, while buffer pH was shown to be particularly critical to the separation and detection. The effect of pH also depended on the electrophoretic mode used. Ways to obtain recurring and selective were suggested.

Determination of toluene diisocyanate in synthetic-rubber track by ion chromatography with ultraviolet detection after alkaline suppressor

In the present work, a novel analytical method was proposed for the determination of toluene diisocyanate （TDI） in syntheticrubber track by ion chromatography （IC） coupled with an ultraviolet detector setting at 212 nm. TDI can be hydrolyzed to toluene diamine （TDA） which can be separated by cation-exchange IC easily. The optimum IC separation was performed on an IonPac CS12A column （150 mm ×4.0 mm） using 20 mmol L^-1 sodium sulfate, 10 mmol L^-1 sulfuric acid and 10% acetonitrile as eluent. It was found that a higher signal response of TDA could be obtained under alkaline condition. A suppressor was used to change the acidic eluent into alkaline one. 0.8 mol L^-1 potassium hydroxide was chosen as the optimum regeneration eluent. With the added suppressor and regenerant, signal response was magnified by about 16 times and lower limit of detection （LOD, 0.13 μg L^-1） was obtained. Within-day relative standard deviation （R.S.D.） was less than 3.6%. The recoveries of TDI spiked in synthetic-rubber track samoles were 96.4-110.6%.

DNA Separation by Capillary Electrophoresis with Ultraviolet Detection using Mixed Synthetic Polymers

The mixtures of two polymers, poly (N,N-dimethylacrylamide) (PDMA) and polyvinylpyrrolidone (PVP) were synthesized and used as the separation medium for double-stranded and single-stranded DNA fragments by capillary electrophoresis with UV detector. On optimal conditions, 2%w/v PDMA + 2%w/v PVP can be used to separate the doublet 123/124bp in pBR322/Hae III Markers.

Trace Determination of Tamoxifen in Biological Fluids Using Hollow Fiber Liquid-Phase Microextraction Followed by High-Performance Liquid Chromatography-Ultraviolet Detection

The applicability of hollow fiber liquid-phase microextraction (HF-LPME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was evaluated for the extraction and determination of tamoxifen (TAM) in biological fluids including human urine and plasma. The drug was extracted from a 15 mL aqueous sample (source phase;SP) into an organic phase impregnated in the pores of the hollow fiber (membrane phase;MP) followed by the back-extraction into a second aqueous solution (receiving phase;RP) located in the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, compositions of SP and RP solutions, extraction time, ionic strength and stirring rate on the extraction efficiency were examined and optimized. An enrichment factor of 360 along with substantial sample clean up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 1 - 500 ng?mL–1 and the limit of detection was found to be 0.5 ng?mL–1 in aqueous medium. A reasonable relative recovery (≥89%) and satisfactory intra-assay (3.7% - 4.2%, n = 3) and inter-assay (7.5% - 7.8%, n = 3) precision illustrated good performance of the analytical procedure in spiked human urine and plasma samples.

Determination of tetraethyl ammonium by ion-pair chromatography with indirect ultraviolet detection using 4-aminophenol hydrochloride as background ultraviolet absorbing reagent

A method was developed for the determination of tetraethyl ammonium （TEA） by reversed-phase ion- pair chromatography with indirect ultraviolet detection, Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 mmol/L 4-aminophenol hydrochloride and 0.15 mmol/L 1-heptanesulfonic acid sodium mixed with 20% （v/v） methanol as mobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit （S/N = 3） for TEA was 0.06 mg/L. The relative standard deviations （n = 5） for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.

Imidazolium ionic liquid as the background ultraviolet absorption reagent for determination of morpholinium cations by high performance liquid chromatography-indirect ultraviolet detection

A novel analytical method was developed for determining morpholinium cations lacking ultraviolet absorption groups.This determination was carried out by high performance liquid chromatographyindirect ultraviolet（HPLC-1UV） detection using imidazolium ionic liquid as background absorption reagents,and imidazolium ionic liquid aq.soln.-organic solvent as mobile phase by a reversed-phase C18 column.The background ultraviolet absorption reagents,imidazolium ionic liquids and organic solvents were investigated.The imidazolium ionic liquid in the mobile phase is not only the background ultraviolet absorption reagent for IUV,but also an active component to improve the separation of morpholinium cations.It was found that morpholinium cations could be adequately determined when0.5 mmol/L 1-ethyl-3-methylimidazolium tetrafluoroborate aq.soln./methanol（80：20,v/v） was used as mobile phase with an IUV detection wavelength of 210 nm.In this study,the baseline separation of Nmethyl,ethylmorpholinium cations（MEMo） and N-methyl.propylmorpholinium cations（MPMo） was successfully achieved in 8.5 min.The detection limits（S/N = 3） for MEMo and MPMo were 0.15 and0.29 mg/L,respectively.This simple and practical method has been successfully applied to the determination of two morpholinium ionic liquids synthesized by the chemistry laboratory.

Olefin-linked covalent organic frameworks with twisted tertiary amine knots for enhanced ultraviolet detection

Though Olefin-linked covalent organic frameworks(oCOFs)possess excellentπ-electron delocalization,the barely reversible olefin linkage brings challenges for oCOFs’synthesis and functionalization.Here,we synthesize new oCOFs with tertiary amine knots which have twisted configuration and electron-donating nature.Investigation into the structural variation and photoelectric performance shows that the twisted configuration of oCOF-TFPA could favor to the intramolecular charge transfer process and reduce the pos-sibility of aggregation-caused quenching.Photoelectrical measurements and electric band structure cal-culation both verify the superiority of this oCOFs’structure in photoelectric sensing.

Separation and identification of moxifloxacin impurities in drug substance by high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform ion cyclotron resonance mass spectrometry

在这份报纸，高效的液体层析结合了紫外察觉， Fourier 变换离子回旋加速器回声团 spectrometry (HPLCUV/FTICRMS ) 方法在 moxifloxacin (MOX ) 为杂质侧面的调查被描述药物质和化学参考书物质。十杂质被 HPLCUV 检测，当八杂质被使用与多重阶段的集体度谱的数据和破碎规则相结合的高精确的分子的团识别时。到我们的知识，另外，五杂质在 MOX 药物质第一次被成立。

Amplified ultraviolet detection of natural DNA based on Mo_6S_(9-x)I_x nanowires

We demonstrate that Mo6S9-xIx nanowires （MoSI NWs） can serve as an excellent signal-intensifying nanomaterial for highly sensitive and label-free detection of DNA by ultraviolet （UV） spectrophotometry. The DNA extinction at 260 nm was greatly enhanced after addition of MoSI NWs solute, and the extinction value was linear with DNA concentration in the range of 0.0289-11.68 μg/mL with the real determination limit of 28.9 ng/mL. The association of DNA with the nanowires was characterized by transmission electronmicroscopy and circular dichroic spectroscopy. The results illustrate that the UV response amplification of DNA in the presence of MoSI NWs is attributed to the greater DNA coverage on the MoSI NW surface and the conformational transformation of DNA due to interaction of DNA with MoSI NWs. MoSI NWs are a promising nano-structured material for developing ultrasensitive sensors for detection of DNA.

高效液相色谱-紫外检测法同时测定类鼻疽患者血浆中亚胺培南、美罗培南和头孢他啶的浓度

目的建立一种快速、经济的高效液相色谱-紫外检测法(HPLC-UV),用于同时测定人血浆中亚胺培南、美罗培南和头孢他啶的药物浓度。方法采用Millipore 10KD超滤离心去蛋白,使用互为内标法,色谱柱为SunFire-C18柱(4.6 mm×250 mm,5µm);预柱为C18柱(4.0 mm×2.1 mm,5µm),流动相为0.1 mol·L^(-1)的3-(N-吗啡啉)丙磺酸(pH=7.0)和乙腈,梯度洗脱,检测波长299nm,流速1.0mL·min^(-1),运行时间30min,进样体积30µL。结果亚胺培南、美罗培南和头孢他啶的保留时间分别为6.699 min、10.795 min和8.722 min。血浆内源性物质对样品的测定无干扰,峰形良好。该方法具有良好的线性、准确度和精密度。不同浓度的样品在–20℃反复冻融、–20℃长期冷冻和4℃(48 h)下均表现出了较高的稳定性。结论该方法操作成本低、专属性强、分离效果好,可用于类鼻疽患者血浆中亚胺培南、美罗培南和头孢他啶治疗药物浓度的测定。

星载紫外相机空间目标探测能力研究

卫星在发生由太阳翼导致的季节性闪烁时反射光谱会向短波偏移,波长更短的紫外段在空间目标太阳翼探测中具有潜在优势。针对空间目标探测,建立了空间目标探测信噪比和探测距离模型。针对模型中影响最大的材料特性,测量了典型卫星材料、太阳翼电池材料等紫外和可见光段的光谱反射率,也分析了模型中探测器和深空背景等其它影响因素。以“实践五号”和“天网5D”卫星为例,验证了紫外在太阳翼探测上的确存在显著优势。结果表明,相对于卫星主体可见光探测,太阳翼紫外探测信噪比增强1.3~1.6倍,由紫外和可见光复合探测距离可提升1.5~1.8倍。并且紫外在临边、掩星模式下,以及卫星变轨中发动机尾焰的探测中较可见光具有明显技术优势,因而紫外探测在空间目标探测中具有明显的费效比和探测能力优势。

Ag/Bi_(2)O_(3)纳米块自供能紫外探测器的制备及性能

为了实现在无外部供能下对紫外光的有效探测,基于Ag修饰的Bi_(2)O_(3)纳米块(Ag/Bi_(2)O_(3))纳米块制备了自供能紫外探测器。通过煅烧法制备Bi_(2)O_(3)纳米块,随后采用室温溶液法在其表面沉积Ag纳米粒子,进而成功制备了Ag/Bi_(2)O_(3)纳米块,且对所制备样品的晶体结构和微观形貌等进行了表征。结果表明,Ag/Bi_(2)O_(3)纳米块的平均尺寸约为1μm,且Ag纳米粒子随机分布在Bi_(2)O_(3)纳米块表面。将涂覆Ag/Bi_(2)O_(3)纳米块的FTO作为工作电极,并进一步构建了自供能紫外探测器。在365 nm的紫外光照射下,Ag/Bi_(2)O_(3)纳米块紫外探测器能在零偏压下实现对紫外光的快速检测,这证实其具有自供能特性。相比于Bi_(2)O_(3)纳米块紫外探测器,Ag/Bi_(2)O_(3)纳米块紫外探测器的光电流得到明显提升,上升和下降时间分别缩短至29.1 ms和40.2 ms,并具有良好的循环稳定性。

感光层厚度对a-GaO_(x)基日盲紫外光电探测器的性能影响研究

为制备高性能日盲紫外光电探测器,采用低温金属有机物化学气相沉积方法制备了非晶氧化镓薄膜。通过对薄膜结构特性测试证明了薄膜的非晶特性,并且薄膜表面较为平坦,光学吸收边位于深紫外波段范围内。在此基础上,研制了日盲紫外光电探测器。随非晶氧化镓感光层厚度由33.2 nm增至133.6 nm,探测器的光电流和暗电流均提升了2个数量级,并且响应度和外量子效率均随感光层厚度提升而增大,探测器的响应度和外量子效率的最大值分别达到2.91 A/W和1419.12%。探测器的厚度依赖特性可归因于界面高缺陷层、光吸收强度以及探测器的几何参数。此外,探测器展现出良好的波长选择性以及时间分辨响应稳定性。

Au修饰ZnO纳米棒的制备及紫外探测性能研究

采用磁控溅射技术和水热法制备金(Au)纳米颗粒修饰的氧化锌(ZnO)纳米棒材料。利用场发射扫描电子显微镜、透射电子显微镜、X射线衍射仪和荧光光谱仪等测试设备对不同溅射功率下的Au纳米颗粒修饰的ZnO纳米棒进行了表征分析。实验结果表明,不同溅射功率下的ZnO纳米棒均呈六方纤锌矿结构,沿晶面(002)择优生长,具有较高的结晶度;修饰后ZnO纳米棒表面附着Au纳米颗粒,能有效增强其紫外光激发强度;当射频溅射功率为80 W时,ZnO纳米棒表现出最佳的紫外探测性能,相比于未修饰的ZnO纳米棒,Au纳米颗粒能抑制ZnO纳米棒的持续光电导(PPC)效应,其紫外探测的响应/恢复时间分别降低了6.05和4.54 s,光暗电流比由9.31提升至32.40,光响应度达到1.94A/W,显著增强了ZnO纳米棒紫外探测的能力。

药用辅料乳糖中痕量亚硝酸盐和硝酸盐的离子色谱-电导/紫外检测研究

目的:建立药用辅料乳糖中痕量亚硝酸盐、硝酸盐的离子色谱-抑制电导(IC-CD)检测法和高效液相色谱-紫外(HPLC-UV)检测法。搭建在线膜抑制系统,结合LC-MS/MS技术进行结构确证,为药用辅料乳糖的前置风险控制提供新的策略。方法:IC-CD检测法和HPLC-UV检测法均采用高容量阴离子交换柱Dionex IonPacTM AS11-HC RFICTM(4.0 mm×250 mm)和保护柱Dionex IonPacTM AS11-HC RFICTM(4.0 mm×50 mm)。IC-CD检测法流动相为氢氧化钾溶液,梯度洗脱,抑制型电导检测器的电导池温度为30℃;HPLC-UV检测法流动相为5 mmol·L^(-1)氢氧化钠溶液,检测波长为210 nm;两种方法的流速均为1.0 mL·min^(-1),柱温均为30℃,进样量均为25μL。结果:两种方法测定亚硝酸根在0.03~10μg·mL^(-1)范围内、硝酸根在0.02~200μg·mL^(-1)范围内线性关系均为良好(r>0.999);亚硝酸根检测限和定量限分别为0.25 ng和0.75 ng,硝酸根检测限和定量限分别为0.25 ng和0.50 ng;回收率在84.00%~100.70%之间;进样精密度RSD(n=6)在0.27%~1.33%之间;均满足检验需求。结论:两种方法均具有灵敏度高、专属性强、分离度好、前处理简单的优势,可表征药用辅料乳糖中痕量亚硝酸盐、硝酸盐的含量,也为其他药用辅料前置风险研究提供新的思路和参考。

高效液相色谱-紫外检测法测定化妆品中咖啡因的含量

建立了高效液相色谱法测定化妆品中咖啡因的含量。试样经甲醇提取稀释后或正己烷分散再用甲醇水溶液反萃提取净化后,采用Waters Atlantis T3色谱柱(4.6 mm×150 mm,5μm)分离,以甲醇和水为流动相梯度洗脱,流速为1.0 mL/min,检测波长为273 nm,柱温为40℃。结果表明,咖啡因在0.2~10 mg/kg的质量浓度范围内呈现良好线性关系,相关系数为0.9999,七种基质三个浓度水平的平均回收率在105.5%~110%之间,RSD在0.7%~4.5%之间,方法的定量限为10 mg/kg。建立的方法具有提取效率高、分析时间短、测试结果准确可靠、重复性好等优点,可适用于化妆品中咖啡因的含量测定。

Organometallic perovskite single crystals grown on lattice-matched substrate for photodetection

In this work,we demonstrate that an organometallic perovskite(OP)single crystal for effective photodetection can be grown on a gold(Au)-decorated substrate using liquid phase epitaxy.The covered gold could both control the shape of the epitaxial layer and act as its electrodes.An MAPbCl3 single crystal and an MAPbBr1.5Cl1.5 single crystal were used as the substrate and the epitaxial layer,respectively.The device,with an Au-perovskite-Au structure,can be fully characterized.Due to the high-quality epitaxial layer,the maximum external quantum efficiency(EQE)value is over 60%under the voltage of
20 V.In addition,the response speed can reach 200 and 500 ns(ns)rise and fall,respectively.Our work provides an effective and promising method to fabricate efficient perovskite-based photodetectors.

紫外可见分光光度计在食品检测中的应用研究

随着社会的发展和科技的进步,食品安全问题已经成为人们关注的焦点。为了确保食品的安全性,需要采取一系列的检测措施,以保障公众的健康。紫外可见分光光度计作为一种高效的分析工具,近年来在食品检测中得到了广泛的应用。基于此,本文阐述紫外可见分光光度计的组成及其特点、紫外可见分光光度计在食品检测中的作用及其在食品检测中的应用。

便携式紫外测油法在突发水环境事件石油类应急监测中的应用

现场快速监测方法在突发环境事件应急监测中发挥着越来越重要的支撑作用。利用便携式紫外测油仪测定了突发环境事件地表水中的石油类。将方法的检出限、精密度和准确度的测定结果与实验室标准方法进行比对,结果表明,方法检出限为0.008mg/L,精密度介于0.40%~4.76%,标准样品测定结果准确,样品加标回收率介于90%~104%,与实验室标准分析方法的相对偏差为6.7%。此方法更加便捷、快速、节省时间、数据时效性强,可及时为突发水环境事件处置提供技术支撑。

低浓度聚丙烯酰胺含量的检测及溶液离子的影响

处理后选矿废水中残余的聚丙烯酰胺(PAM)影响回水水质及其回用,本文为建立一种低检出限的低浓度PAM快速检测方法,在190~300 nm波长范围内建立了4种类型及分子量不同PAM的紫外吸收光谱,研究了不同浓度K^(+)和Ca^(2+)对PAM浓度检测的影响,并通过原子力显微镜(AFM)分析了PAM分子构象的变化.结果表明,4种类型的PAM峰值吸光度均在波长194 nm处测得,PAM浓度与吸光度之间具有强线性关系(R^(2)>0.98),检出限均低于0.1 mg·L^(-1),但PAM类型影响其浓度与吸光度的线性关系.随着K^(+)和Ca^(2+)浓度的增加,PAM溶液吸光度特征峰的强度逐渐降低并降速减缓,最大吸收波长不断红移,分别沉积在二氧化硅和金基底的APAM-3与CPAM-12的表面形貌粗糙度分别随K^(+)和Ca^(2+)浓度的增加而增大,说明PAM分子链在溶液中的构象逐渐变卷曲,使紫外光谱特征吸收峰的峰值降低,10、100 mmol·L^(-1) K^(+)与1、10 mmol·L^(-1) Ca^(2+)对PAM构象变化的影响程度基本相同.本研究实现聚丙烯酰胺的快速定量检测,对开展选矿水处理中聚丙烯酰胺的迁移规律研究具有重要意义.