OPTICS LETTERS
·
2022
·Vol. 48
·期 1
·139-142
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IF 3.56
Zhenyu Ma,Jing Sun,Sijie Zhou,WenJun Shan,Yunxiang Yan,Yunxiang Yan,Yongjun Liu
A novel, to the best of our knowledge, type of compact pH fiber sensor combined with a hydrogel based on the whispering gallery mode (WGM) is proposed and integrates a liquid crystal (LC) microdroplet in a capillary in a compact structure as small as 180 µm. In the research, the hydrogel performs both as a supporting frame and a responsive material that causes morphological deformation of the LC microdroplet with pH variation. Moreover, a new phenomenon of pH-induced LC refractive index variation is observed and applied in the pH measurement, so that the acid itself can also lead the LC microdroplet structure transition. Thus, the WGM method is applied to detect the composite effect simultaneously to improve the sensing capability. The sensitivity of the sensor in the pH range from 4.55 to 6.86 reaches 3.19 nm/pH. The response time is short, within 60 s. The simple and compact structure of the sensor reduces the cost and enhances the stability, which is of great potential for biomedical pH measurement.
研究领域:
生物医学工程
·
光学工程
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PubMed
高影响因子
SPECTROSCOPY LETTERS
·
2017
·
IF 0.794
Hongliang Wang,Baohua Liu,Zhengguang Li,Lei Yang
Dye leakage and the nonlinear relationship between absorbance and pH affect the pH measurement precision of absorption-based optic sensors and limit their application. Based on the preparation of a transparent sol–gel thin film with a phenol red indicator, this work assumed that the absorbancies had an exponential relationship to the concentrations of the indicator, and the multi-wavelength equation for the pH was derived as follows:
where n is the exponential coefficient, e1, e2, and e3 are the extinction coefficient ratios, and R is the ratio of the absorbancies. The calculation parameters for an immobilized phenol red film were pKa = 8.577, e1 = 0.0191, e2 = 1.530, e3 = 0.2992, and n = 0.6322, while those for an immobilized phenol red/Triton X-100 film were pKa = 8.612, e1 = 0.0507, e2 = 1.501, e3 = 0.3687, and n = 0.3931. The correspondence between the calculated pKa and the pKa from the calibration curve verifies the equation. The calculation parameters remain stable as the indicator content is increased, but change with an increase in the Triton X-100 content. Using the equation, the calculated pH shows stable behavior over a long duration regardless of dye leakage, and the calculated precision is 0.0053. The method provides drift-free and precise water pH measurements for R that is not dependent on the total concentration of the indicator, and can be applied to online monitoring.
研究领域:
分析化学
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生物医学工程
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DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2019
·Vol. 17
·期 4
·939-944
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IF 3.49
Leixia Mei,Suyun He,Li Zhang,Keming Xu,Wenying Zhong
We report the synthesis and self-assembly of fluorescent peptide amphiphiles (NBD-PA) composed of a fluorescent NBD probe and a peptide derivative VVAADD with a C12-alkyl-chain as the linker (NBD-C12-VVAADD). The self-assembly of NBD-PA formed beta-sheet structures at neutral pH in aqueous solution, contributed to an ∼10-fold increase in the fluorescence and quantum yield of NBD molecules, and conferred a supramolecular hydrogel with excellent viscoelastic properties, while gel-to-sol transition of NBD-PA occurred rapidly when the pH value was adjusted to strongly alkaline (e.g. pH 11). Through the pH-responsive self-assembly behavior, we further explored the relationship between fluorescence of NBD-PA and pH values. Interestingly, the fluorescence of the NBD-PA system exhibited an excellent sigmoidal function relationship (R2 = 0.9999) with the alkaline pH values, which enabled accurate pH measurement regardless of salt types and ionic strength of solvents. Furthermore, the fluorescence of NBD-PA was fully reversible upon cycles of pH shifts, with the chemical structure of NBD-PA well-maintained throughout the process. These features of NBD-PA would facilitate the design of in situ pH detection systems as well as pH-responsive actuators for various applications in future.
研究领域:
生物化学
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材料科学
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分析化学
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PubMed
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2024
·Vol. 40
·期 2
·287-292
·
IF 3.1
Li Yaohua,Wang Wei
Intracellular pH (pH i ) is a fundamental indicator of cellular physiological state, regulating cellular state and function, and has important research values. Although various probes for measuring intracellular pH were available, it is challenging to reflect pH i in real-time and reversible manners. Herein, we developed a whole-cell bioluminescent (BL) probe based on wild type BL bacteria, photobacterium phosphoreum ( P. phosphoreum ), to determine and image pH i . The dependence of BL intensity of P. phosphoreum on pH values of culture solutions was established. It was found that BL intensity could respond to the change of pH values rapidly and reversibly. We further revealed that P. phosphoreum maintained pH homeostasis in the extracellular pH (pH e ) within the range of 5.0–7.0, while intracellular pH homeostasis was destroyed at the alkaline pH e . This method opens up the enormous potential of BL bacteria as an alternative to fluorescence for monitoring and imaging pH i .
研究领域:
生物化学
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细胞生物学
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生物物理学
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微生物学
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生物医学工程
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DOI
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Yong Zhao,Ming Lei,Shi-Xuan Liu,Qiang Zhao
A hydrogel-coated optical fiber surface plasmon resonance (SPR) sensor based on MMF-SMF-MMF structure has been fabricated for pH measurements. When the solutions with difference pH values contacting the sensing probe, the amount of the dissociated carboxylic ions in the hydrogel will change according to the pH value of the solution. This process will modify the volume and refractive index of the hydrogel, which results in a shift of the SPR wavelength. The experimental sensor is able to indicate pH variations in a wide pH range from 1 to 12, and the maximum pH sensitivity of the proposed sensor can reach 13 nm/pH at higher pH region (8–10 pH). The influence of temperature (in the range of 20 °C–40 °C) on SPR wavelength is found to be weak. Further, the sensor possesses remarkable repeatability and excellent stability. Due to the wide measuring range and simple fabrication process, the sensor is promising to be used for the pH measurements.
研究领域:
传感技术
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材料科学
·
光学工程
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高影响因子
MEASUREMENT
·
2024
·
IF 5.2
Bin Yin,Zhuxuan Jiang,Shilin Liu,Guofeng Sang,Yanzhi Lv,Muguang Wang,Shiying Xiao,Beilei Wu,Qichao Wang,Li Pei,Songhua Wu
A composite Fabry-Perot (F-P) fiber optic sensor based on the vernier effect is fabricated, and experiments confirmed that it can be used to simultaneously measure underwater temperature and pH. The fiber optic sensor fabricated with single mode fiber (SMF) − multi mode fiber (MMF) − seven core fiber (SCF) − quartz capillary tube (QCT) − no core fiber (NCF) structures has contained a silane coupling agent-polyvinyl alcohol/graphene oxide (SCA-PVA/GO) hybrid multilayer film to enhance the sensor performance. Two types of sensors are fabricated, one with a plane end face and another with a tapered end surface, which named as sensor 1 and sensor 2, respectively. Their performance are experimentally demonstrated. Within the temperature range of 15°C-35°C and the pH range of 7.55–9.21, the sensitivities of sensor 1 to temperature and pH are 82.94 pm/°C and 1.16 dB/pH, while the corresponding values of sensor 2 are 39.26 pm/°C and 0.4 dB/pH. Experimental results demonstrated that the sensitivities of sensor 1 to temperature and pH are higher than that of sensor 2. But compared with sensor 2, sensor 1 has higher values of crosstalk and random error. By contrast, sensor 2 maintain a good linear relationship with the environmental dual parameters, allowing for the simultaneous measurement of underwater temperature and pH. Moreover, both sensors demonstrate good stability and reversibility when the temperature and pH are varied. Furthermore, the pH response times of the two sensors are less than 0.5 s, with a recovery time of 2 s. Thus, the proposed sensors with outstanding stability, reversibility, repeatability, and rapid response times will have a broad range of applications in the fields of marine environment monitoring, water quality detection, and food and medical device safety testing.
研究领域:
海洋环境监测
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水质量检测
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光学传感
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材料科学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2022
·
IF 11.357
Lin-Fang Li,Zhe Chen,Pai Liu,Yun-Hong Zhang
Accurately measuring the pH of atmospheric aerosols is a prerequisite for understanding the multiphase chemistry that profoundly affects the environment and climate systems. Despite the advancements of experimental techniques for in situ pH measurements in aerosols, current studies are limited to measuring the static pH of aerosol microdroplets with an unperturbed composition. This steady-state scenario, however, deviates from the real-world aerosols undergoing atmospheric aging reactions, specifically, those characterized with a spontaneous displacement of strong bases (or acids) with high volatility. Here, we introduce a continuous and in situ measurement of aerosol pH by using a 4-mercaptopyridine-functionalized silver nanoparticle probe and surface-enhanced Raman spectroscopy. We find that the ammonium depletion─a spontaneous displacement of ammonium by dicarboxylic acid salts─continuously acidifies aerosol water over time. The decaying trends of pH in the aerosols under various humidity conditions can be unified with a universal exponential function. Such an exponentially decaying function further indicates that the ammonium depletion reaction is a self-limiting process. Our technique can be applied to study the dynamic change of aerosol acidity during the complex atmospheric aging processes, toward elucidating their implications on atmospheric chloride, nitrate, and ammonium cycles.
研究领域:
环境科学
·
大气化学
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分析化学
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DOI
PubMed
高影响因子
ANALYTICAL LETTERS
·
2021
·
IF 2.329
Ping-Rong Zhou,Zhang-Feng Tang,Ke-Su Wei,Ya Wan,Yu-Meng Gao,Yan-Mei Liang,Xiu-Fang Yan,Jun Bin,Chao Kang
Ultraviolet-visible absorption spectrometry is used for the determination of many inorganic, organic, and biological species. However, poor selectivity limits its applications for quantitative analysis in complex mixtures. In this work, its mathematical selectivity was explored using trilinear decomposition on spectral-pH measurements for the selective determination of two flavonoids in three Chinese herbal medicines. Through introducing a pH mode, second-order spectral pH data were constructed per sample. By using trilinear decomposition on the calibration and prediction samples, the rutin signals were extracted from lonicerae japonicae flos, perillae folium, and perillae fructus samples, respectively. Novel second-order calibration was developed for interference-free determination of rutin in these medicines followed by univariate regression of the decomposed intensity versus concentration. The predicted 95% confidence intervals for the concentration of rutin in these samples were 5.19 ± 0.16, 5.81 ± 0.10, and 7.00 ± 0.36 μg mL−1, respectively. These results were validated by high performance liquid chromatography (HPLC). Similarly, interference-free determination of isorhamnetin was achieved in these materials. By increasing the selectivity of ultraviolet-visible spectroscopy with trilinear decomposition, the requirements for sample preparation and chemical separation are reduced. The developed spectral pH second-order calibration allows direct analysis of complex samples by ultraviolet-visible absorption spectrometry due to the mathematical selectivity.
研究领域:
分析化学
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药物分析
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光谱学
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DOI
高影响因子
MICROCHIMICA ACTA
·
2023
·Vol. 190
·期 4
·1-9
·
IF 5.7
Du Ning,Zhang Guohui,Hou Pengkun,Zhang Hao,Guan Ruifang
An organic fluorescent probe, citric acid-1,3-Propanediamine-Rhodamine B ( CPR ) was synthesized to determine pH of ordinary Portland cement requiring only a small sample size (less than 500 μL cement leachate). The SEM, XRD, and FTIR investigations demonstrate that citric acid-1,3-Propanediamine are polymer dots with a fusiform structure. Ratio pH probe is constructed by rhodamine B with polymer dots, which exhibits a linear response in high alkaline range. A 6-fold increase in fluorescence intensity (455 nm) is achieved at pH from 12.00 to 13.25. Combined with measurements of the isothermal calorimeter, mineral composition, and microscopic morphology, variation of pH is used to evaluate the changes of components during hydration. Furthermore, CPR can be applied to measure pH of high-dose pulverized fuel ash blending systems, the non-pure cement with slightly lower alkalinity. Graphical
研究领域:
材料科学
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分析化学
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水泥技术
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荧光探针
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高分子化学
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DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Hangqian Li,Shu Wang,Shulu Zheng,Tengyue Fang,Huilin Shu,Yi Xu,Xianghui Guo,Eric P. Achterberg,Liyang Zhan,Jian Ma
The development of field-deployable methods and instruments for the measurement of pH and other carbonate parameters is important for the assessment of the marine carbon cycle , ocean acidification and marine carbon dioxide removal techniques. In this study, a high-precision fully automated integrated syringe-pump-based environmental-water analyzer for pH ( i SEA-pH) was developed. The pH is determined spectrophotometrically using purified indicator dye with a high precision (better than ±0.001) and high frequency (3.5 min/sample). For the short-term analysis, the measurement frequency was 18 h −1 , which revealed pH = 7.8148 ± 0.0005 (n = 104) for aged surface seawater (S = 35) from the western Pacific. For long-term analysis, the measurement frequency was 2 h −1 for 4 days, and the results showed that pH = 7.8148 ± 0.0010 (n = 200). Three commonly used pH indicators (meta-cresol purple, thymol blue and phenol red) were purified with improved flash chromatography procedures. The autonomous i SEA-pH can automatically correct for the influence of temperature, salinity and other factors on pH measurements to achieve rapid and accurate on-site measurements, which meet the “climate” goal of the Global Ocean Acidification Observing Network (uncertainty is ±0.003). Three identical i SEA-pH systems were developed and successfully applied in mesocosm experiments and several coastal and open ocean cruises with excellent in field performance.
研究领域:
环境科学
·
海洋化学
·
海洋学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
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