紫外双波长法

维生素B族是一组水溶性维生素，包括多种不同的维生素，如B1、B2、B3、B5、B6、B9等。它们参与人体生长发育、新陈代谢及生命活动等过程，包括维持皮肤和肌肉的健康，增进免疫系统和神经系统功能，促进细胞生长和分裂等，是所有人体组织必不可少的营养素。福立仪器采用LC5090Plus高效液相色谱仪，使用双波长法高效准确测定上述6种维生素B。 分析检测方法 方法提要试样经反相液相色谱分离，紫外检测器检测,根据色谱峰的保留时间定性仪器配置 福立LC5090Plus高效液相色谱仪:配备LC5090Plus在线脱气机+LC5090Plus四元低压输液泵+LC5090Plus自动进样器+LC5090Plus柱温箱+紫外检测器色谱柱PolyPak C18 AQ，柱长250mm，内径4.6mm，粒径5μm 分析检测数据 6种维生素B混合对照品溶液色谱图（285nm)6种维生素B混合对照品溶液色谱图（210nm)福立液相色谱紫外检测器具备双波长功能，能够同时在两个不同的紫外波长下监测和记录化合物的信号，在复杂样品分析中表现出更高的选择性和准确性&zwnj 。 双波长检测的优势高选择性：通过在特定波长下检测特定化合物，可以减少样品中其他组分的干扰。灵敏度提高：对于某些化合物，选择其最大吸收波长进行检测可以提高检测灵敏度。数据验证，准确度提高：通过比较两个波长下的检测结果，可以更可靠地分析检测化合物。 多组分同时分析，实现高效率：当样品中含有多种需要检测的组分时，双波长检测可以在一次运行中同时获得各组分数据，提高实验效率。

中国科学院深圳先进技术研究院生物医学与健康工程研究所研发团队研发了首款短波长激发时间与光谱分辨新型双光子显微镜，该显微镜创新性地采用中心波长为520 纳米的锁模飞秒光纤激光器作为双光子激发光源，可以有效地激发短波长波段荧光团，利用连接光谱仪的时间相关单光子计数模块，可实现荧光光谱和荧光寿命的同时检测。该技术可以实现紫外波段自体荧光的有效激发与探测，极大地拓展了双光子成像技术的应用范围，为无创观测生物样品及生命过程提供了一种新的研究工具。该成果于近日发表于生物医学光学领域知名期刊《生物医学光学快报》上。生物体中，普遍存在着具有内源性荧光团的生物分子，内源性荧光团的三维成像可以在不干扰生物环境的情况下对重要生物过程进行无创体内检查，如代谢变化、形态改变和疾病进展，是组织成像和跟踪细胞代谢过程的有力工具。双光子显微镜具有天然的光学切片能力，无需物理切割就可以实现生物组织的三维高分辨成像。双光子显微镜跟内源性荧光团的结合可以实现活体生物组织无标记成像，对很多生命活动的研究具有非常重要的意义。然而，传统的双光子显微镜是以钛宝石激光器作为光源，只能对可见光波段的内源性荧光团进行探测，很难探测到信息更丰富的短波长荧光团。 深圳先进院郑炜团队首次研制出采用520纳米超快激发源搭建光谱分辨的双光子荧光寿命成像系统，可以有效激发和探测传统双光子显微系统无法成像的一系列短波长荧光团。为了验证该系统的实用性，研究团队首先系统地评估了生物组织中典型的短波内源性荧光团纯化学样品在520纳米激发下的荧光寿命和光谱特性，包括荧光分子酪氨酸、色氨酸、血清素、烟酸、吡哆醇和NADH，以及角蛋白、弹性蛋白和血红蛋白。 随后，研究团队对不同的生物组织进行了成像，包括离体大鼠食管组织和离体大鼠口腔面颊组织。结果表明，该系统可以在不需要任何外加造影剂的情况下，为生物系统提供高分辨率的三维形态信息和物理化学信息。此外，研究人员探索了短波长的内源性荧光团在食管壁中的分布，结果表明，该系统可以很清晰展示食管的不同分层结构。结合寿命和光谱信息，系统可以明确识别食管内部多层结构的不同信号来源，定量区分不同组织成分在食管壁的位置和数量，区分食管分层结构。 最后，研究团队进一步对小鼠皮肤进行了活体三维扫描成像，并基于短波内源荧光团在体内捕获了小鼠耳廓内白细胞的迁移，实现了典型免疫反应微环境中白细胞募集和变形运动的动力学过程的可视化，以及随时间的荧光寿命测量。“紫外荧光强度图像可以显示生物组织的精细结构，紫外荧光寿命信息可以区分红细胞和白细胞，两者结合可以无标记追踪免疫细胞在伤口和正常组织的运动情况，这些结果验证了我们开发的系统在天然组织环境中监测免疫反应的能力。”郑炜介绍。深圳先进院医工所助理研究员吴婷为文章第一作者，深圳先进院医工所郑炜研究员、李慧副研究员，北京大学物理学院施可彬研究员为共同通讯作者

近日，来自中国科学院安徽光学精密机械研究所、先进激光技术安徽省实验室、中国科学技术大学、法国滨海大学大气物理化学实验室联合研究团队发表了《基于钕铁硼环形磁体阵列的双中红外波长法拉第旋转光谱NOx传感器》论文。Recently, the joint research team from Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Advanced Laser Technology Laboratory of Anhui Province, University of Science and Technology of China, Laboratoire de Physicochimie de l′ Atmosph`ere, Universit´ e du Littoral C&circ ote d′ Opale, published an academic papers Dual mid-infrared wavelength Faraday rotation spectroscopy NOx sensor based on NdFeB ring magnet array.氮氧化物（NOx，包括二氧化氮（NO2）和一氧化氮（NO））是对流层臭氧的重要前体，同时也影响羟基和过氧基自由基的浓度。大多数气态化合物在被氧化和从空气中去除或转化成其他化学物质时，都会直接或间接接触到NOx。在典型的羟基自由基水平下，NOx的寿命取决于季节和光化学反应速率，通常为几小时。根据IPCC第六次评估报告，NOx的排放导致净正向变暖，因为它既形成短期臭氧（变暖），又破坏环境甲烷（冷却）。此外，NOx还导致酸沉降以及化学烟雾和气溶胶的形成。NO和NO2在大气光化学反应中起着核心作用，针对它们的检测有助于理解这两种气体的来源和去向，以及研究陆地生态系统与大气之间的NOx交换通量。Nitrogen oxides (NOx, the sum of nitrogen dioxide (NO2) and nitric oxide (NO)) are important precursors of tropospheric ozone, and they also influence the concentration of hydroxyl and peroxyl radicals. Most of the compounds that are oxidized and removed from the air or converted to other chemical species are in direct or indirect contact with NOx. At typical hydroxyl radical levels, the life time of NOx depends on the season and the photochemical reaction rate, which is typically a few hours. According to the IPCC sixth assessment report, the emissions of NOx result in net-positive warming from the formation of short-term ozone (warming) and the destruction of ambient methane (cooling). Additionally, NOx contributes to acid deposition and the formation of chemical smog and aerosols. Since NO and NO2 play a central role in atmospheric photochemical reactions, their simultaneous detection helps to understand the sources and sinks of these two gases, in addition to studying the NOx exchange fluxes between terrestrial ecosystems and the atmosphere.化学发光检测（NO + O3 → NO2 + O2 + hν）是测量NOx的传统方法。在通过化学发光反应（Mo + 3NO2 → MoO3 + 3NO）测量之前，NO2首先需要在高温（~325°C）下转化为NO。虽然这种方法被广泛使用，但其他氧化氮化合物，如过乙酰亚硝酸酯（PAN）和硝酸（HNO3），可能会在测量NOx浓度时引起交叉干扰。同时，这种方法不能区分NO和NO2。红外吸收法也可用于测量NO和NO2。在这种方法中，通常需要通过转化器将NO2还原为NO。由于NO和NO2是顺磁分子，法拉第旋转光谱（FRS）可以用作实现其高度敏感和选择性检测的潜在方法。FRS通过检测气态介质在纵向磁场中引起的光偏振状态的变化，实现对物种浓度的高灵敏度检测。该方法通过测量光学色散实现气体浓度的检测，因此其动态测量范围比基于比尔-兰伯定律的吸收光谱（动态范围上限≤10%）更大。FRS的另一个重要优势是它对于抗磁性分子（如水和二氧化碳）具有较强的抗干扰能力，从而使其具有高样品特异性。Chemiluminescence detection (NO+O3→NO2+O2+hν) is the conventional method for measuring NOx. NO2 first needs to be converted to NO at high temperature (~325 ◦ C) before it can be measured by chemiluminescence reaction (Mo+3NO2→MoO3+3NO). Although this method is more widely used, other oxidized nitrogen compounds, such as peroxyacetyl nitrate (PAN) and nitric acid (HNO3), can cause cross-interference in the measurement of NOx concentrations. Simultaneously, this method is non-selective in discriminating between NO and NO2. The infrared absorption method can also be used for NO and NO2 measurements. In this method, NO2 usually needs to be reduced to NO by the converter. As NO and NO2 are paramagnetic molecules, Faraday rotation spectroscopy (FRS) can be used as a potential method to achieve their highly sensitive and selective detection. FRS enables highly sensitive detection of species concentrations by detecting changes in the polarization state of light induced by a gaseous medium immersed in a longitudinal magnetic field. This method realizes the detection of gas concentration by measuring optical dispersion, so it has a higher dynamic measurement range than absorption spectroscopy (dynamic range upper limit ≤10%) based on Beer-Lambert law. Another significant advantage of FRS is that it is reasonably immune to diamagnetic species (e.g., water and carbon dioxide), which allows it to exhibit high sample specificity. 大多数这些报道的FRS传感器使用螺线管提供外部纵向磁场，从而导致能耗高和产生过多焦耳热。同时产生目标磁场所需的高电流交流电路会产生不受控制的电磁干扰（EMI），通常会降低FRS传感器的长期稳定性。此外，当前报道的FRS传感器只能在吸收池中进行单组分测量，不能满足复杂环境中同时进行多组分测量的需求。Most of these reported FRS sensors use solenoid coils to provide an external longitudinal magnetic field, which makes them suffer from high power consumption and excessive Joule heat generation. The high-current alternating current circuit required to generate the target magnetic field produces uncontrolled electromagnetic interference (EMI), which usually deteriorates the long-term stability of the FRS sensors. In addition, the currently reported FRS sensors are only capable of single-component measurements in the absorption cell and cannot meet the demand for simultaneous multi-component measurements in complex environments.在本研究中，提出了一种新型的低能耗FRS传感器，基于钕铁硼（NdFeB）环形磁体阵列，实现在单个吸收池中同时检测NO和NO2。分析了同轴双波长赫里奥特池（DWHC）的环形磁体阵列的磁场分布特性。使用两台室温连续波中红外量子级联激光器（QCL），波长分别为5.33 µ m（1875.81 cm&minus 1）和6.2 µ m（1613.25 cm&minus 1），同时探测DWHC内的磁光效应。通过对激光波长进行高频调制，有效抑制了1/f噪声。优化了双波长FRS NOx传感器的性能，包括调制幅度、调制频率、样品气压和分析器偏置角。本研究提出的FRS传感器为现场可部署的微量气体检测设备提供了理想解决方案。宁波海尔欣光电科技有限公司为此研究提供了HPPD-M-B 前置放大制冷一体型碲镉汞（MCT）光电探测器，用以分别检测2个激光束。In the present work, a novel low-power FRS sensor based on a neodymium-iron-boron (NdFeB) ring magnet array was proposed to achieve simultaneous detection of NO and NO2 in a single absorption cell. The magnetic field distribution characteristics of a ring magnet array coaxial to a dual-wavelength Herriott cell (DWHC) were analyzed. Two room-temperature continuous wave mid-infrared quantum cascade lasers (QCL) with wavelengths of 5.33 µ m (1875.81 cm&minus 1) and 6.2 µ m (1613.25 cm&minus 1), respectively, were used simultaneously to probe magneto-optical effects within the DWHC. The 1/f noise was effectively suppressed by high-frequency modulation of the laser wavelength. The performance of the dual-wavelength FRS NOx sensor was optimized with respect to modulation amplitude, modulation frequency, sample gas pressure, and analyzer offset angle. The FRS sensor proposed in this work provides a preferable solution for field deployable trace gas detection equipment. The laser detected by two TEC-cooled mid-infrared thermoelectrically cooled mercury-cadmium- telluride (MCT) photodetectors (Healthy Photon, model HPPD-B- 10–150 K).(a) Schematic diagram of the dual mid-infrared wavelength FRS NOx sensor based on a NdFeB ring magnet array (b) Optical layout of the FRS NOx sensor.thermoelectrically cooled mercury-cadmium- telluride (MCT) photodetectors (Healthy Photon, model HPPD-B- 10–150 K),结论本研究开发了一种基于NdFeB环形磁铁阵列的双中红外波长FRS传感器，用于同时检测NO2和NO。在光学路径长度为23.7米，积分时间为100秒的条件下，NO2和NO的检测限分别为0.58 ppb和0.95 ppb。高频激光波长调制与外部静态磁场相结合，最大程度地减小了低频噪声对FRS信号的影响。基于有限元方法分析了使用的永磁体阵列的磁场分布特性，帮助确定与其耦合的吸收池长度。采用双波长赫里奥特池放大两种不同偏振光波长与氮氧化物分子之间的相互作用，从而实现了在单个吸收池内对两种顺磁分子的高灵敏度检测。本文提出的FRS NOx传感器在大气环境监测或生态系统NOx通量观测等领域，具有进一步发展成为便携式、可在实地使用的仪器的巨大潜力。Conclusion In this work, a dual mid-infrared wavelength FRS sensor based on a NdFeB ring magnet array was developed for the simultaneous detection of NO2 and NO. The detection limits for NO2 and NO were 0.58 ppb and 0.95 ppb, respectively, at an optical path length of 23.7 m and an integration time of 100 s. High frequency laser wavelength modulation was combined with an external static magnetic field to minimize the effect of low frequency noise on the FRS signal. The magnetic field distribution characteristics of the used permanent magnet array were analyzed based on the finite element method, which helped to determine the length of the absorption cell coupled to it. A dual-wavelength Herriott cell was used to amplify the interaction between two different wavelengths of linearly polarized light and nitrogen oxide molecules, thus achieving highly sensitive detection of two paramagnetic molecules within a single absorption cell. The FRS NOx sensor presented in this work shows great potential for further development into a portable, field-deployable instrument with applications in atmospheric environmental monitoring or ecosystem NOx flux observation. (a) Schematic diagram of a dual-wavelength Herriott cell (DWHC) with a NdFeB ring magnet array (b) Characteristics of the magnetic inductance line distribution around a NdFeB ring magnet array (c) Ray tracing results in a DWHC (d) Spot distribution on a concave mirror.Optimization of laser modulation frequency for the dual mid-infrared wavelength FRS NOx sensor.Optimization of laser modulation amplitude for the dual mid-infrared wavelength FRS NOx sensor.(a), (b) Measured FRS NOx signal as a function of analyzer angle (c), (d) Calculated FRS NOx noise as a function of analyzer angle (e), (f) Calculated SNR as a function of analyzer angle.Measured FRS NOx signal amplitude as a function of sample pressure.(a) , (b) FRS signals for different concentrations of NOx (c), (d) Linear dependence of FRS signal amplitude as a function of NOx concentration.Allan deviation plot of the dual mid-infrared wavelength FRS NOx sensor.Reference:Yuan Cao, Kun Liu, Ruifeng Wang, Guishi Wang, xiaoming Gao, Weidong Chen，Dual mid-infrared wavelength Faraday rotation spectroscopy NOx sensor based on NdFeB ring magnet array, Sensors & Actuators: B. Chemical 388 (2023) 133805https://doi.org/10.1016/j.snb.2023.133805