大气中SO2顺序注射光度测定方法的初步研究

基于SO2在微碱性条件下使孔雀绿褪色的反应原理, 结合顺序注射进样技术建立了光度分析测定大气中SO2的方法. 对试剂加入顺序、各种试剂的浓度、注入体积、反应系统流速等实验参数进行了优化. 采用顺序注射进样, 极大地节省了试剂和试样的用量, 显著地提高了分析速度, 可达到60样·h-1. 方法的线性响应范围0.25～4.0 μg·mL-1, 检出限为0.15 μg·mL-1, 11次重复测定的相对标准偏差为1.5%. 对实际样品的回收率为94%～108%.     

流动注射在线分离富集-火焰原子吸收光谱法测定环境水样中Cr(Ⅲ)和Cr(Ⅵ)的形态

采用单阀阴离子和阳离子交换树脂微柱并联 ,两柱交替采样逆向洗脱流动注射在线分离富集环境水样中Cr(Ⅲ )和Cr(Ⅵ ) ,分别用 15 %HNO3和 8%NH4 NO3洗脱 ,火焰原子吸收光谱法直接检测。富集 1min时Cr(Ⅲ )和Cr(Ⅵ )的特征浓度分别为 :1 5 0 μg·L- 1 和 1 39μg·L- 1 ,Cr(Ⅲ )和Cr(Ⅵ )检出限 (3σ)分别为 1 0 3μg·L- 1 和 0 5 4 μg·L- 1 ;相对标准偏差 (10 μg·L- 1 )分别为 :3 4 1%和 1 80 % ,分析样品加标回收率在 93 5 %～ 10 7 5 %之间。     

反射式流通池顺序注射光度检测系统的研制

提出一种反射式流通池用于过程分析光度检测系统 ,可以明显地抑制折光指数效应产生的干扰。以发光二极管为光源 ,采用多股光纤分别与流通池 ,光源 ,检测器耦合 ,实现对透射后反射回的光谱检测。以Cl- Hg(SCN) 2 Fe(Ⅲ )反应显色体系为模型对系统的实验参数进行了优化。讨论了试剂注入量、进样量、载流流速、试剂注入次序等参数对检测结果的影响。方法的线性范围为 0～ 10 0mg·L-1(相关系数r =0 998) ;分析精度 (RSD ,n =11)为 1 5 % ;检出限为 1 2mg·L-1;分析速度为 30个样·h-1;对自来水和海水的回收率分别为 95 %和 10 4 %。     

酪氨酸-钼(Ⅵ)的荧光猝灭法测定酪氨酸

本文基于钼 (Ⅵ )对酪氨酸的荧光具有猝灭的特性 ,拟订了一种测定酪氨酸的方法 ,该方法激发波长为 2 78nm ,发射波长为 30 5nm。线性范围为 0 0 1～ 14 4μg·mL-1,检测限为 6ng·mL-1,对于 0 18μg·mL-1的酪氨酸测定 10次的相对标准偏差为 1 13%。用该方法测定了啤酒及葡萄酒中酪氨酸的含量     

甲氧氯普胺和盐酸普鲁卡因顺序注射光谱研究和测定

在酸性介质中,铈(Ⅳ)与甲氧氯普胺和盐酸普鲁卡因反应生成不稳定的红色产物,研究了不同条件下的光谱吸收曲线,初步探讨了反应机理,并据此建立了顺序注射光度法测定甲氧氯普胺和盐酸普鲁卡因的新方法。测定甲氧氯普胺方法的线性范围9.71～116.6 μg·mL-1,检出限6.5 μg·mL-1,进样频率45 h-1。测定盐酸普鲁卡因的方法的线性范围10.0～130.0 μg·mL-1,检出限7.4 μg·mL-1,进样频率45 h-1。用于针剂和胃复安药片中甲氧氯普胺的含量以及针剂中盐酸普鲁卡因含量的测定,并与标准测定方法对照,经统计学处理无显著性差异,结果满意。     

流动注射蒸气发生原子吸收光谱测定痕量铜

建立了流动注射蒸气发生原子吸收光谱测定铜的新方法。使含有微量邻菲咯啉的样品溶液与硼氢化钠溶液汇合并反应生成蒸气态物质。在Ar载气下随反应液进入气液分离器分离 ,并进入石英管原子化器在 1 0 0 0℃下检测。在 5 0 0 μL进样体积下 ,铜的检出限为 1 8μg·L- 1 ,相对标准偏差为 2 6%(n =1 1 ,c=1 0 0 μg·L- 1 )。采样频率为 1 4 4样·h- 1 。分析标准参考物质大米粉和头发样品中的铜 ,结果与标准值一致     

流动注射-导数火焰原子吸收光谱测定植物油中的铜、锌

提出了流动注射 导数火焰原子吸收光谱测定植物油中的微量铜和锌的新方法。流动注射进样技术克服了常规火焰原子吸收法耗样量大和基体干扰严重的缺点。导数技术应用于火焰原子吸收可提高方法的灵敏度和信号的选择性。流动注射与导数技术相结合应用于火焰原子吸收成功地测定了植物油中的微量铜和锌。铜和锌的特征浓度分别为 0 0 0 4 0 ,0 0 0 12 μg·mL-1,相对标准偏差在 1 1%～ 5 1%的范围内。     

流动注射在线螯合树脂双柱预富集火焰原子吸收法测定痕量铜、铅、镉和锰

本文采用流动注射在线阳离子螯合树脂双柱预富集 火焰原子吸收法 ,测定了痕量的铜、铅、镉和锰 ,灵敏度分别提高 33、5 0、37和 2 9倍 ,分析速度为 6 0次·h-1;对于 0 0 5 μg·mL-1Cu2 +、0 2 5 μg·mL-1Pb2 +、0 0 2 5 μg·mL-1Cd2 +和 0 0 5 μg·mL-1Mn2 +溶液 ,测定的相对标准偏差分别为 2 2 1%、3 2 4%、1 93%和3 6 6 % (n =11) ;对标准物质 (人发、小麦及猪肝 )进行了测定 ,结果与标准值相符。此法应用于饮用水和环境水样中铜、铅、镉和锰的测定 ,获得了满意的结果。     

流动注射荧光分光光度法测定DNA的研究

本文研究了中药有效成分盐酸小蘖碱与DNA的荧光光谱性质 ,并应用流动注射技术测定DNA的浓度 ,该法线性范围 0～ 12 μg·mL-1 ,检出限为 ( 3σ) 7 3ng·mL-1 ,相对标准偏差≤ 3 1% ,应用于合成样品的测定 ,取得满意的结果     

芯片式微型流通池顺序注射化学发光法测定水中的亚硝酸根

设计了一种芯片式流通池和顺序注射技术联用,基于在酸性介质中NO-₂与H₂O₂反应生成不稳定的过氧亚硝酸, 在碱性环境中猝灭为过氧亚硝酸盐迅速分解产生化学发光的原理,测定了环境水中痕量的亚硝酸根离子浓度;和常规的顺序注射进样方式不同,将流通池作为储存管的一部分,在顺序注射进样条件下可以迅速跟踪捕捉化学发光反应信号;采用阳离子交换树脂进行水样前处理,消除了阳离子的干扰。NO-₂浓度在1×10-6～1×10-4 mol·L-1范围内和发光强度呈线性关系。方法的检测限为6.8×10-7 mol·L-1。对浓度为1×10-5 mol·L-1 的试液,11次重复测量的相对标准偏差为2.7% ,回收率在90%～99% 之间,分析频率为80 h-1。     

Evanescent-wave optical Cr VI sensor with a flexible fused-silica capillary as a transducer

A light-guiding, flexible fused-silica (FFS) capillary has been used in designing an optical fiber Cr VI sensor for monitoring Cr VI ions in water samples. The FFS capillary is similar to a conventional silica optical fiber in that it can guide light in the wavelength region from the UV to the near IR but different from a conventional optical fiber in that it is a tubular waveguide. The inner surface of the FFS capillary is fused silica, which one can modify to design an optical fiber chemical sensor. The FFS capillary has a cladding layer plus a protective polymer coating on its outside surface. The cladding layer ensures the ability of the FFS capillary to guide light. The protective coating increases the FFS capillary's mechanical strength and makes it robust for practical applications. Compared with conventional silica optical fibers, it is much easier and more feasible to use this FFS capillary to fabricate long-path (tens of meters to thousands of meters) evanescent-wave based chemical sensors. We describe a Cr VI sensor based on the intrinsic evanescent-wave absorption by Cr VI ions in a water sample filled inside the capillary as an example of use of a FFS capillary in chemical sensor design. This simple sensor, using a 30 m light-guiding FFS capillary as a transducer, has the capability of detecting as little as 31 parts in 10(9) of Cr VI in a water sample, which is close to the detection limit of some sophisticated, expensive analytical instruments.     

磁免疫和荧光免疫传感器的构建及其在检测甲胎蛋白中的应用

甲胎蛋白(AFP)是常见的肝癌肿瘤标志物,在早期诊断方面起到重要作用。分别设计构建了磁免疫和荧光免疫传感器并将其应用于AFP的定量检测。在磁免疫传感器中,采用免疫磁珠代替传统固相载体,实现了目标物的快速分离;利用标记抗体上的辣根过氧化物酶(HRP)催化底物显色,根据底物吸光度值的大小进行定量检测。构建的AFP检测方法的检出限为3.6 ng·mL-1,线性范围为10~80 ng·mL-1。在荧光免疫传感器中,将碲化镉量子点(CdTe QDs)的荧光作为信号输出,并通过同时将多个CdTe QDs连接在纳米硅球表面实现信号放大,通过测量量子点荧光强度实现定量检测。该方法AFP检出限为4.2 ng·mL-1,线性范围为5~150 ng·mL-1。所设计的两种传感器均具有特异性强、灵敏度高的特点,为AFP的检测提供了新的思路和方法。     

在监测固相反应过程中显微红外和漫反射红外光谱方法的比较

文中利用傅里叶红外显微镜和漫反射红外光谱监测聚苯乙烯磺酰氯树脂与乙醇胺在不同温度下的反应程度,对两种方法进行了比较。结果证明漫反射红外光谱是简单有效的方法,而显微红外光谱是研究单个树脂小球之间差异的有效手段。     

New calibration method for position detector for simultaneous measurements of force constants and local viscosity in optical tweezers

We present a new method to calibrate a quadrant photodiode used as position detector to monitor latex beads trapped in optical tweezers. The method combines the dragging Stoke’s force with the thermal noise analysis (power spectral density (PSD)) of the Brownian motion of the trapped bead. Position detector calibrations used in other similar methods normally utilise a bead attached to the coverslip: the voltage-position calibration factor is found by translating the bead across the waist of a laser beam. The so determined calibration factor is then assumed to be the same when beads are investigated in the optical trap. This procedure presents some drawbacks since attached beads can be affected by proximity effects due to the coverslip glass surface which alter the position sensor response itself. On the contrary, our method is able to provide, simultaneously, the calibration factor, the trap stiffness, and the local viscosity of the medium making use of a single trapped bead.     

黄铁矿处理重金属废水的光谱表征

将反射光谱和吸收光谱用于黄铁矿处理酸性重金属废水的研究,探讨了黄铁矿的表面反应以及黄铁矿与重金属的相互作用。漫反射红外光谱分析证实,在处理废水过程中,黄铁矿中表面羟基与重金属离子发生反应;并通过考察黄铁矿中碳酸盐,合理解释了黄铁矿处理酸性重金属废水后的溶液自然均趋于中性(pH 7)的现象。可见区的反射光谱用于表征处理过程中的黄铁矿的颗粒及比表面变化,解释了黄铁矿在重复使用时其活性反而增强的原因。吸收光谱及XPS表征表明,黄铁矿处理含Cr(Ⅵ)废水,是一个由Cr(Ⅵ)到Cr3+再到Cr(OH)₃的吸附沉淀过程。     

在线捕集分离联用技术对食品调料中砷形态分析方法研究

成功建立了冷捕集-气相色谱-氢化物发生-原子荧光光谱分析测定食品调料(酱油和醋)中砷形态的方法。以脱脂棉为分离介质,用液氮对样品中生成的气态砷化合物进行冷捕集,常温下不同砷形态化合物即可以实现基线分离,随后被原子荧光光谱检测。实验考查了酸介质的种类和酸度、KBH₄溶液的浓度、反应时间以及载气(He)的流量等实验条件对测定结果的影响。结果表明,在优化后的实验条件下,方法对As(Ⅲ),As(Ⅴ),MMA(Ⅴ)和DMA(Ⅴ)的检出限分别为0.2,0.2,0.3,0.8 ng·mL-1,对酱油和醋As(Ⅲ),As(Ⅴ),MMA(Ⅴ)和DMA(Ⅴ)的回收率为93.07%～103.54%。与传统的液相色谱分离方法相比,该方法不用对样品进行特殊前处理,分析速度快,灵敏度高,适合于对食品调料中砷形态尤其是无机砷形态的准确、快速分析测定。     

荧光免疫及磁免疫层析法检测莱克多巴胺的研究

分别将量子点和超顺纳米磁珠作为荧光探针和磁信号探针应用于免疫反应中,构建了检测莱克多巴胺的荧光免疫和磁免疫层析的分析方法,并成功应用于尿液中莱克多巴胺的检测。两种方法均基于免疫竞争模式,在荧光免疫分析方法中,量子点偶联上识别莱克多巴胺的抗体,样品中莱克多巴胺和包被在ELISA板上莱克多巴胺的完全抗原竞争结合量子点,样品中莱克多巴胺的浓度越高,ELISA板上吸附的量子点越少,所测荧光强度值越低,该方法的检出限为1 ng·mL-1,检测时间为4 h。在磁免疫层析方法中,检测线上特异性捕获的纳米磁珠颜色的深浅和尿液中莱克多巴胺浓度成反比例关系,即莱克多巴胺的浓度越高,检测线的颜色越浅,该方法的定性检出限为10 ng·mL-1,检测时间为15 min。两种方法各有优缺点,基于量子点的荧光免疫分析法在痕量检测和定量分析方面具有优势,而磁免疫层析法更适合于现场快速检测。     

流动注射化学发光法测定山奈酚

采用流动注射技术,研究了高锰酸钾-山奈酚-过氧化氢体系的化学发光行为,对影响化学发光强度的因素进行了试验,建立了流动注射化学发光法测定山奈酚的新方法.方法检出限为1×10-10g·mL-1,线性范围为1.0×10-7-1.0×10-4g·mL-1.对1.0×10-6g·mL-1的山奈酚平行测定11次,其RSD为2.1%...     

A particle trapping chip using the wide and uniform slit formed by a deformable membrane with air bubble plugs

We present a high-efficient particle trapping chip, where a wide and uniform slit is formed by a deformable membrane barrier with air bubble plugs. The previous particle trapping methods based on membrane barriers resulted in low trapping efficiency due to the non-uniform slit gap between the membrane and the substrate, especially at the side walls of rectangular channel. In the present method, the air bubble plugs remained in the extended microchannel during sample filling process, block the particle passage at the both side ends of the membrane, thus all particles flow through the uniform slit gap. Therefore, high-efficient particle trapping without particle loss can be achieved. The present particle trapping chip was composed of three layers: pneumatic (top), membrane and channel (bottom) layers. The membrane was deformed by the pneumatic pressure applied from the top layer. In the experimental study using 10.3 μm-diameter polystyrene beads, the membrane barrier with the air bubble plugs successfully trapped the injected beads with the trapping efficiency of 100% at the flow rate of 10 μl/min, while the barrier without the air bubble plugs showed low efficiency of 20%. At the increased flow rate of 20 μl/min, beads were still trapped with trapping efficiency over 98% in the present device. By using a mixture of 5.7 and 10.3 μm-diameter beads, we also verified the present method was capable to trap and release the beads selectively according to their size with the release efficiency of 95.1%. The present simple and effective particle trapping device is applicable for the high-efficient bioparticle isolation and recovery in the micro total analysis system.     

Acoustic transmission across a roughened fluid-fluid interface

A set of tank experiments was performed to investigate acoustic transmission across a roughened fluid-fluid interface with the intention to test heuristic Bragg scattering predictions used to explain observations of anomalous transmission in field experiments. In the tank experiments, two immiscible fluids (vegetable oil floating on glycerin) formed the layers. Small polystyrene beads were floated at the interface to simulate roughness. An array of hydrophones placed in the bottom layer (glycerin) was used to measure the acoustic levels transmitted across the interface. This array was also employed as a beamformer to determine the apparent angle and sound speed of the scattered signals. Data were acquired at subcritical grazing angles in the frequency range of 100-200 kHz for three different bead diameters and for various configurations in which the locations of the beads floating on the interface were varied. Results of these measurements demonstrated that a significant amount of acoustic energy can be scattered into the bottom layer by beads floating at the interface. The scattered levels increased with increasing bead diameter. However, discrepancies occurred between observed propagation properties and the Bragg predictions. By comparing the processed tank data to a computer simulation of the same it was determined that these discrepancies are a consequence of near-field reception of the scattering by the bead array and ignoring the directionality of the scattering by the beads. Consequences to observations made in field experiments are discussed.