Optical Oxygen Sensor Research Articles

Analysis of long-term optical performance of phosphorescent oxygen sensing polymeric nanofibers

Photostability assessments of polymeric optical oxygen sensors are typically of limited duration (orders of magnitude lower than real application durations), involve irreproducible setups, ignore sensitivity changes and evaluate a limited number of samples. Using custom LED aging bays, continuous photobleaching (>1 month) was used to assess oxygen-sensitive polysulfone-polycaprolactone core-shell electrospun nanofibers with incorporated platinum (II)- or palladium (II)-based porphyrins. Increased [porphyrin] corresponded to greater initial brightness and more rapid photobleaching. Nevertheless, the rapid solvent evaporation characteristic of electrospinning allowed for linear Stern-Volmer plots for solids loading as high as 10 wt%. UV excitation resulted in a greater initial photobleaching rate for both brightness and sensitivity, but these decreases ended after ~1 week; green-aged samples continued to photobleach out to 1000 h. Via straightforward monitoring of brightness, oxygen sensitivity and Stern-Volmer linearity, this long-term photobleaching assessment protocol can be used to screen dozens of polymer sensors for real-life applications.

Self‐degassing SARA ATRP mediated by Na2S2O4 with no external additives

ABSTRACTThe supplemental activator and reducing agent (SARA) atom transfer radical polymerization (ATRP) mediated by Na2S2O4 in the presence of air, without external deoxygenation or additional oxygen scavengers, is reported for several vinyl monomers: methyl acrylate (MA), n‐butyl acrylate (n‐BA), methyl methacrylate (MMA), 2‐(dimethylamino)ethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether acrylate (OEOA), and styrene (Sty). The polymerizations can be conducted in aqueous medium or using organic/water mixtures as solvent, with low concentration of copper, near room temperature. In the absence of any external deoxygenation, several well‐defined homopolymers and block copolymers were obtained (Ð < 1.3). The evolution of the oxygen concentration during the polymerizations was monitored with an optical oxygen sensor. The consumption of oxygen prior polymerization in ethanol/water mixtures was attributed to the combined presence of Na2S2O4 and alkyl halide initiator, which led to a lower initiation efficiency (Ieff). This could be overcome by decreasing the headspace volume of the reaction. The system reported exhibited the potential to be scalable, which is very relevant from an industrial standpoint. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 145–153

Investigation of Gas Transport Properties of PEMFC Catalyst Layers by Using a Microfluidic Device

Gas transport properties of catalyst layers (CLs) used in proton exchange membrane fuel cells (PEMFCs) are one of the important factors which affects cell performance. The gas transport properties are strongly affected by the porous structure of the CLs. In this study, a measurement system of gas diffusion flux through the CLs by using a microfluidic device was developed. Parallel channels were made on a Si chip by microfabrication techniques. Air and nitrogen were supplied to the two parallel channels in the device, respectively. Oxygen was transferred to a nitrogen flow channel through the CL under a rib between the two channels. Oxygen partial pressure in the nitrogen flow channel was measured at the outlet of the channel by using an optical oxygen sensor. The porous structure of the measured CLs was characterized. Effective gas diffusivity and tortuosity factor of the CLs can be calculated based on the measured gas transfer and porous structure properties. Several types of CLs were fabricated and characterized. The thickness and overall porosity of the CLs were evaluated from scanning electron microscopy and weight measurement. Pore size distribution and effective porosity were evaluated by using nitrogen physisorption measurement. Then effective diffusivity of CLs can be calculated by measuring oxygen partial pressure at the inlet and outlet of the flow channel. The CL, which has 1.0 of ionomer to carbon ratio, was evaluated. Oxygen partial pressure at the outlet of the nitrogen flow channel decreases with flow rate as shown in Figure 1. Effective gas diffusivities obtained from each flow rate showed almost constant value. Tortuosity factor was calculated from the effective diffusivity and measured structural properties and indicated around 3. This evaluation method was applied to the CLs containing a different type of carbon materials, which show different porous structure. Adding multi-walled carbon nanotube in the CL(1) instead of carbon black resulted in an increase of effective gas diffusivity, while geometrical porosity was decreased. Acknowledgments A part of this work was financially supported by JSPS KAKENHI Grant Number 16K18028. This study was supported by Osaka University Nanofabrication Platform [F-18-OS-0006] in Nanotechnology Platform Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. References T. Suzuki, R. Hashizume and M. Hayase, J. Power Sources, 286, 109 (2015). Figure 1

The Effect of Modified Nanodiamonds on the Wettability of the Surface of an Optical Oxygen Sensor and Biological Fouling During Long-Term in Situ Measurements

A method is proposed for controlling the wettability of the surface of a fluorinated material and for controlling its biofouling by introducing modified nanodiamonds into the structure. The optimal modification conditions were determined by means of a set of methods based on the example of a molecular oxygen sensor. They do not lead to a change in other functional properties of the material, such as the calibration curve and response time. In vitro tests have shown that a small amount of aminated nanodiamonds gives the surface bactericidal properties, but with a high content, improved adhesion of the biomaterial is observed due to a decrease in hydrophobicity. Long-term in situ tests under conditions simulating a bioreactor with actively growing biomass showed an almost complete absence of biological fouling of the modified material and revealed a significant fouling of the sensor from traditionally used polystyrene.

Hypoxia‐induced depolarization of pulmonary arterial smooth muscle cells relies on simultaneous inhibition of K+‐currents and redox state alterations

Hypoxic pulmonary vasoconstriction (HPV) is a physiological response to localized alveolar hypoxia that is intrinsic to the pulmonary circulation. By hypoxia‐induced contraction of pulmonary arterial smooth muscle cells (PASMCs), pulmonary capillary blood flow is redirected to alveolar areas of high oxygen partial pressure (pO2), thus maintaining the ventilation‐perfusion ratio. Although the principle of HPV was recognized decades ago the underlying pathway still remains elusive.Voltage gated K+‐channels (Kv‐channels) are known to be redox‐sensitive and crucial for mediating membrane potential in PASMCs ‐ thereby controlling Ca2+‐entry and subsequently vascular tone. Here, we investigated whether acute hypoxia alters the redox state of isolated PASMCs from mice and if this impacts Kv‐channel activity, membrane potential and intracellular Ca2+‐ level.Kv‐currents and membrane potential in response to hypoxia or the oxidizing agent H2O2 were investigated by whole cell patch clamp experiments (voltage and current clamp, resp.) on freshly isolated murine PASMCs. Simultaneously, pO2 was recorded using an optical oxygen sensor and intracellular Ca2+ was measured by ratiometric FURA‐2 imaging. The redox state was monitored by Raman spectroscopy using an excitation wavelength that was in resonance with the hemeproteins (532 nm).Raman‐spectra values for reduced myoglobin (1607 cm−1) and cytochrome c (1622 cm−1) both increased upon exposure of PASMCs to hypoxia (4 % O2) and returned to the initial value upon reverting to normoxia (21 % O2), thus indicating a shift in the cells' redox state. In accordance, Kv‐currents were dose‐dependently inhibited by hypoxia and H2O2, resulting in a depolarization from −37,5 ± 2 mV (before) to −28.09 ± 2 mV after exposure to hypoxia (Mean ± SEM; n = 23; p = < 0,001; paired t‐test). The oxidizing agent H2O2 (124 nM) mimicked this effect under normoxic conditions by elevating the membrane potential of the PASMCs from −37.4 ± 3 mV (before) to −25,2 ± 4 mV upon application of 124 nM H2O2 (Mean ± SEM; n = 5, p = 0,005, paired t‐test) ‐ thereby triggering a rise in intracellular Ca2+.In conclusion, hypoxia induced a shift in redox state in PASMCs, thereby mediating the inhibition of KV‐channels. The resulting depolarization and Ca2+‐entry may account for the contraction of PASMCs – thus initiating HPV.Support or Funding InformationThis study was funded by the German Research Foundation (DFG, CRC 1213) and the Swedish Research Council (Grant 2016‐04220).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Luminescent oxygen probes based on TbIII complexes chemically bonded to polydimethylsiloxane

In this work, the functionalization degree of siloxane crosslinkers by allyldiphenylphosphine oxide (adppo) and its effect on the performance of a lanthanide-based optical oxygen sensor were evaluated. Linear poly(dimethyl-co-hydromethylsiloxane) (PMS) and cyclic tetramethylcyclotetrasiloxane (D4i) crosslinkers were functionalized with different concentrations of adppo to chemically bond the [Tb(dcba)3]·1/2H2O (dcba = dichlorobenzoate) complex. Mechanically stable luminescent silicone membranes were obtained after the curing of the poly(dimethylsiloxane)-vinyl terminated siloxane backbone with the pre-functionalized crosslinkers. Sensing materials exhibit green emission upon 350 nm excitation, and their luminescent properties are dependent of functionalization degree of the crosslinkers. The luminescent sensor materials show fully reversible response and non-linear Stern-Volmer plots, which are fitted by two quenching parameter model, with highest KSV of 0.08930%−1 when using functionalized D4i as crosslinker and complex concentration of 0.75%.

Benzo[ghi]perylene & coronene as ratiometric reversible optical oxygen nano-sensors

The development of novel single molecular probe based optical ratiometric oxygen sensor with simple fabrication, high sensitivity, and linear response is highly desirable. Herein, benzo[ghi]perylene (BzP) and coronene (Cron) were explored as dual-emissive ratiometric oxygen nano-sensors that displayed linear plots at a low probe concentration (6 μM). The sensor fabrication was simple, and the probes exhibited efficient fluorescence quenching of monomer emission by molecular oxygen. However, the excimer emission of probe remained unaffected. Thus a ratiometric method is developed based on the dual emitting luminophore. The method can be used to estimate dissolved oxygen in liquids and 5–100% of oxygen concentration in gaseous mixtures.

Experimental research on fiber optic oxygen sensor based on fluorescence quenching principle

基于荧光淬灭原理的光纤氧传感器一直是许多研究工作的重点。介绍了一种制作简单、成本低的光纤氧传感器制造方法。该方法基于荧光淬灭原理，在光纤末端涂覆荧光材料铂八乙基卟啉(PtOEP)实现的。传感器中荧光材料被395nm的紫光激发，并由Y形光纤引导，使用广州犀谱光电USB2000+光谱仪记录荧光的发光强度时序图。最后得到的PtOEP的(<i>I</i>₀/<i>I</i>₁₀₀)-1的值为0.78，即光纤氧传感器的灵敏度为0.78，而且，斯特恩-沃尔默(Stern-Volmer)图显示出很好的线性特性。从氧气到空气环境的响应时间为24 s，从空气环境到氧气的响应时间是5 s。结果表明，基于荧光淬灭原理的光纤氧传感器具有较高的灵敏度和更快的响应时间。

Development of a fibre optic oxygen sensor for respiratory monitoring in the intensive care unit

Arterial oxygen tension is commonly measured by means of intermittent arterial gas sampling. This technique is unable to detect within-breath oxygen tension changes that may be observed in mechanically ventilated patients, especially in the presence of lung injury. Moreover, it may not afford sufficient time resolution to detect potentially injurious settings of the mechanical ventilation itself. Continuous and rapid arterial oxygen tension measurement could detect within-breath changes in pulmonary gas exchange and offer clinically important feedback for the management of mechanical ventilation therapy in real time. We developed a novel fibre optic intravascular oxygen tension sensor, measured its fast response time in vitro, tested its blood clotting resistance over a period of 24 hours, and its capacity to measure arterial oxygen tension in vivo in a pig model of uninjured lung. This short communication will review the main steps of this collaborative project’s progress to date, highlighting the technology’s strengths, together with future potential for translation to a clinical scenario.

Optical oxygen sensors based on microfibers formed from fluorinated copolymers

Polymeric microfibers, particularly the fluorinated copolymers’ fibers, are promising functional materials for photoelectric devices, sensing, and energy storage due to their various surface characteristics. However, to obtain the high fluorine content copolymer-based fibers with considerable uniformity is likely to be especially challenging, which seriously debilitates their applications in sensor devices. Herein, for the first time, we presented a high fluorine content platinum porphyrin-grafted poly(isobutyl methacrylate-co-dodecafluoroheptyl methacrylate) copolymers (PtTFPP-p(IBM-co-DFHMA)) microfibrous thin-films used as optical oxygen sensors. The porous thin-film frameworks were formed of uniform microfibers, which afforded an exceptional improvement in sensitivity and exhibited 584% higher sensitivity than the solid sensing film owing to the large specific surface area, porous structures and oxygen diffusion enhancement by fluorine elements. Additionally, the remarkable emission intensity-changing characteristic of the microfiber sensing film under various air pressures facilitates convenient visualization of pressure distributions on film surface. The characteristics are particularly important for the computational fluid dynamics simulations in various sensing fields such as unsteady flow visualization and unsteady pressure measurements, etc. Owing to its attractive advantages and versatile performance, fluorine-containing copolymers fibers are expected to provide a new strategy for the rational design of high performance gas sensor devices.

Highly flexible and solution-processed organic photodiodes and their application to optical luminescent oxygen sensors

Abstract We present a solution-processed flexible organic photodiode (f-OPD) with a bulk heterojunction (BHJ) structure based on a blend of poly (3-hexylthiophene-2,5-diyl) and 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61 (P3HT:PCBM). We used Cs2CO3-doped polyethyleneimine ethoxylated (d-PEIE) as the electron transport layer (ETL) material, which significantly improved the electron injection properties of the f-OPD. Compared with f-OPDs with conventional ETL materials such as Cs2CO3, the external quantum efficiency (EQE) of the d-PEIE-based f-OPD was highly improved. Analytical results showed that the d-PEIE reduced the work function of the cathode, thereby facilitating the efficiency of electron injection from the active layer (AL) to the cathode of the f-OPD. In addition, after 10,000 cycles of tensile bending at a bending radius of 5 mm, the normalized ID variation (ID/ID0) in the d-PEIE-based f-OPD remained above 90%, indicating an excellent device bending stability. Finally, f-OPD-based luminescent oxygen (O2) sensors were successfully fabricated consisting of a photoluminescent O2 sensing film, a light source, and an f-OPD. The O2 sensors based on d-PEIE-based f-OPDs showed the highest photocurrent and O2 sensitivity in relation to the O2 concentration compared with O2 sensors based on f-OPDs with conventional ETL materials.

Tuning photophysical properties of phosphorescent benzoporphyrin complexes via 1-step π-extension

Complexes of benzoporphyrins are highly promising for application in optical oxygen sensors, as triplet sensitizers for generation of singlet oxygen and upconversion based on triplet-triplet annihilation (TTA). Particularly, they benefit from efficient absorption in red part of the spectrum and strong NIR phosphorescence. In this contribution, we investigate different strategies of tuning the photophysical properties of these readily available complexes via 1-step modification. The new π-extended derivatives are obtained via Friedel-Crafts acylation of tetraphenyltetrabenzoporphyrin (TPTBP) complexes and by Suzuki or Sonogashira cross-coupling reaction of the tetrabromo-substituted benzoporphyrins. The Soret and Q absorption bands of the tetra-substituted dyes shift bathochromically by about 15 nm compared to the parent TPTBP compounds. The modified dyes retain their NIR phosphorescent properties and feature slight improvement of the quantum yield. Application in optical oxygen sensing materials and triplet-triplet annihilation-based upconversion systems is demonstrated.

Experimental investigation on detonation dynamics through a reactivity sink

This article reports on an experimental investigation into dynamical behaviours of detonation in non-uniform mixtures, generated from stoichiometric propane–oxygen, oxygen and ethane, with initial temperature and pressure 290 K and 20 kPa, respectively. Composition gradients are parallel to the direction of detonation propagation, with an equivalence ratio (ER) that first decreases from lean values and then increases to rich ones. Composition distributions are characterized according to the depth of the ER sink. Gradients are generated in a 50 × 50-mm2-square cross-section and a 665-mm total length chamber. The mixture components are injected separately in the pre-evacuated chamber in their order of decreasing density through porous plates at the chamber top-end to ensure planar filling of the chamber. Non-uniform distributions are then precisely controlled as a function of time by means of optical oxygen sensors. A Chapman–Jouguet (CJ) detonation is transmitted at the chamber bottom-end from a 3.6-m-long driver tube. Fast pressure transducers, sooted plates and Schlieren visualizations coupled with high-speed cameras are used to characterize the longitudinal velocity, cellular structure and transmission, failure and re-initiation mechanisms of the detonation front. Shallowest ER sinks produce the supercritical transmission mode of the CJ detonation with continuous adaptation of velocity and multicellular structure to local composition. Deepest sinks lead to the subcritical behaviour characterized by sudden detonation failure from shock-flame decoupling when ER decreases, and without detonation re-initiation when ER increases again. Intermediate sink depths generate critical behaviour with detonation re-initiat ion at chamber walls from expanding combustion kernels and reflected transverse Mach waves and then from SWACER retro-active mechanism. An elaboration of the failure criterion used in a previous study is found to well predict conditions for shock-flame decoupling.

Photochromic Porous and Nonporous Viologen-Based Metal–Organic Frameworks for Visually Detecting Oxygen

The detection of the oxygen molecule is of particular interest due to various applications in chemical, biological, and environmental areas, and the typical materials of detecting O2 such as Clark-type electodes and optical oxygen sensors suffer from disadvantages such as insensitivity or usage of expensive instrument. In this paper, we present a nonporous two-dimensional viologen-based metal–organic frameworks consisting of pseudo-left- and right-handed helical chains [Cd(CPBPY)(o-BDC)(H2O)]·H2O (CPBPY = N-(3-carboxyphenyl)-4,4′-bipyridinium, o-BDC = o-benzenedicarboxylate) (1) that exhibits a slow photochromism under a vacuum, inert atmosphere, and even exposure to oxygen, and a three-dimensional porous 6-connected pcu topological metal–organic framework [Cd3(CPBPY)2(BDC)3]·DMF·H2O (BDC = 1,4-benzenedicarboxylate) (2), which displays rapid photochromism only under a vacuum or inert atmosphere. The photochromic product 2′ can quickly and conveniently detect O2 by naked eye recognition of color change. Th...

Silver Nanowire-Induced Sensitivity Enhancement of Optical Oxygen Sensors Based on AgNWs–Palladium Octaethylporphine–Poly(methyl methacrylate) Microfiber Mats Prepared by Electrospinning

Sensitivity enhancement of optical oxygen sensors is crucial for the characterization of nearly anoxic systems and oxygen quantification in trace amounts. In this work, for the first time we presented the introduction of silver nanowires (AgNWs) as a sensitivity booster for optical oxygen sensors based on AgNWs–palladium octaethylporphine–poly(methyl methacrylate) (AgNWs@PdOEP–PMMA) microfiber mats prepared by electrospinning. Herein, a series of sensing microfiber mats with different loading ratios of high aspect ratio AgNWs were fabricated, and the corresponding sensitivity enhancement was systematically investigated. With increasing incorporated ratios, the AgNWs@PdOEP–PMMA-sensing microfiber mats exhibited a swift response (approx. 1.8 s) and a dramatic sensitivity enhancement (by 243% for the range of oxygen concentration 0−10% and 235% for the range of oxygen concentration 0–100%) when compared to the pure PdOEP–PMMA microfiber mat. Additionally, the as-prepared sensing films were experimentally confirmed to be highly photostable and reproducible. The advantages of AgNW-induced sensitivity enhancement could be useful for the rational design and realization of revolutionary highly sensitive sensors and expected to be readily applicable to many other high-performance gas sensor devices.

Optical oxygen sensing with quantum dot conjugates

Abstract The ability to track and quantify changes in oxygen concentration as a function of disease progression or therapy is crucial to advance targeted chemotherapeutics. New non-invasive sensors must be developed that are small enough to penetrate into tissue and monitor dynamic changes with high resolution in real time. One way to address this challenge is with the use of nanoparticle-based sensors. This review details the design, synthesis, and characterization of optical oxygen sensors that combine a fluorescent semiconductor quantum dot (QD) with an oxygen-responsive phosphorescent molecule. The QD may have multifaceted roles in these constructs, serving as an internal standard for ratiometric sensing, as an antenna for multiphoton absorption, and as an energy transfer donor for the attendant phosphorescent molecule. Solid-state devices may be prepared by embedding the two components in a polymer matrix. Alternatively, solution-phase sensors can be synthesized by covalent conjugation, self-assembly in organic solvents, or micelle encapsulation in aqueous media. Several sensors have been used for biological imaging and oxygen sensing, demonstrating that these constructs can quantify oxygen in biological systems.

Oxygen Optode Sensors: Principle, Characterization, Calibration, and Application in the Ocean

Recently, measurements of oxygen concentration in the ocean – one of the most classical parameters in chemical oceanography – are experiencing a revival. This is not surprising, given the key role of oxygen for assessing the status of the marine carbon cycle and feeling the pulse of the biological pump. The revival, however, has to a large extent been driven by the availability of robust optical oxygen sensors and their painstakingly thorough characterization. For autonomous observations, oxygen optodes are the sensors of choice: They are used abundantly on Biogeochemical-Argo floats, gliders and other autonomous oceanographic observation platforms. Still, data quality and accuracy are often suboptimal, in some part because sensor and data treatment are not always straightforward and/or sensor characteristics are not adequately taken into account. Here, we want to summarize the current knowledge about oxygen optodes, their working principle as well as their behaviour with respect to oxygen, temperature, hydrostatic pressure, and response time. The focus will lie on the most widely used and accepted optodes made by Aanderaa and Sea-Bird. We revisit the essentials and caveats of in-situ in air calibration as well as of time response correction for profiling applications, and provide requirements for a successful field deployment. In addition, all required steps to post-correct oxygen optode data will be discussed. We hope this summary will serve as a comprehensive, yet concise reference to help people get started with oxygen observations, ensure successful sensor deployments and acquisition of highest quality data, and facilitate post-treatment of oxygen data. In the end, we hope that this will lead to more and higher-quality oxygen observations and help to advance our understanding of ocean biogeochemistry in a changing ocean.

Phosphorescence Tuning through Heavy Atom Placement in Unsymmetrical Difluoroboron β-Diketonate Materials.

Difluoroboron β-diketonates (BF2 bdks) show both fluorescence (F) and room-temperature phosphorescence (RTP) when confined to a rigid matrix, such as poly(lactic acid). These materials have been utilized as optical oxygen sensors (e.g., in tumors, wounds, and cells). Spectral features include charge transfer (CT) from the major aromatic donor to the dioxaborine acceptor. A series of naphthyl-phenyl dyes (BF2 nbm) (1-6) were prepared to test heavy-atom placement effects. The BF2 nbm dye (1) was substituted with Br on naphthyl (2), phenyl (3), or both rings (4) to tailor the fluorescence/phosphorescence ratio and RTP lifetime-important features for designing O2 sensing dyes by means of the heavy atom effect. Computational studies identify the naphthyl ring as the major donor. Thus, Br substitution on the naphthyl ring produced greater effects on the optical properties, such as increased RTP intensity and decreased RTP lifetime compared to phenyl substitution. However, for electron-donating piperidyl-phenyl dyes (5), the phenyl aromatic is the major donor. As a result, Br substitution on the naphthyl ring (6) did not alter the optical properties significantly. Experimental data and computational modeling show the importance of Br position. The S1 and T1 states are described by two singly occupied MOs (SOMOs). When both of these SOMOs have substantial amplitude on the heavy atom, passage from S1 to T1 and emission from T1 to S0 are both favored. This shortens the excited-state lifetimes and enhances phosphorescence.

A background-subtraction strategy leads to ratiometric sensing of oxygen without recalibration.

Luminescence-quenching based optical oxygen sensors have wide applications in many fields, which have already replaced almost 40% of the commercial market share dominated previously by the Clark oxygen electrode. The majority of optical oxygen sensors are based on lifetime measurement, which are precise, but are relatively expensive, and require high-speed electronics and detecting circuits. Alternatively, oxygen concentration can be measured via a luminescence intensity change, which is a referenced approach according to the Stern-Volmer equation. However, luminescence intensity based measurement tends to be highly influenced by background light. At a given sensor composition, different instrumentation setups, sensor surface roughnesses and thicknesses, and environmental light will result in significantly different calibration curves and sensitivities. This makes luminescence-intensity based optical sensors almost impossible to use practically, because each sensor needs to be recalibrated before use, and the calibration curve each time is quite different. We have solved this problem by introducing a new background-subtraction strategy. After background subtraction, oxygen sensors with different probe concentrations, instrumentation setups, surface roughnesses, supporting matrixes, and at different temperatures present identical calibration curves. This could greatly reduce the calibration task during practical use. Combined with the advantages of low price and a simple optical configuration, the new method will significantly promote wider applications of optical oxygen sensors.

トリス（4,7-ジフェニル-1,10-フェナントロリン）ルテニウム（II） を内包したゲル微粒子による光学型溶存酸素センサ

トリス（4,7-ジフェニル-1,10-フェナントロリン）ルテニウム（II） を内包したゲル微粒子による光学型溶存酸素センサ