scholarly journals Fluorescence Sensing of Caffeine in Tea Beverages with 3,5-diaminobenzoic Acid

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 819 ◽  
Author(s):  
Chenxu Du ◽  
Chaoqun Ma ◽  
Jiao Gu ◽  
Lei Li ◽  
Guoqing Chen

A rapid, selective and sensitive method for the detection of caffeine in tea infusion and tea beverages are proposed by using 3,5-diaminobenzoic acid as a fluorescent probe. The 3,5-diaminobenzoic acid emits strong fluorescence around 410 nm under the excitation of light at 280 nm. Both the molecular electrostatic potential analysis and fluorescent lifetime measurement proved that the existence of caffeine can quench the fluorescence of 3,5-diaminobenzoic acid. Under the optimal experimental parameters, the 3,5-diaminobenzoic acid was used as a fluorescent probe to detect the caffeine aqueous solution. There exists a good linear relationship between the fluorescence quenching of the fluorescent probe and the concentration of caffeine in the range of 0.1–100 μM, with recovery within 96.0 to 106.2%, while the limit of detection of caffeine is 0.03 μM. This method shows a high selectivity for caffeine. The caffeine content in different tea infusions and tea beverages has been determined and compared with the results from HPLC measurement.

2020 ◽  
pp. 174751982097392
Author(s):  
Qihua You ◽  
Yihua Zhuo ◽  
Yadong Feng ◽  
Yujuan Xiao ◽  
Yanyu Zhang ◽  
...  

A highly selective OFF–ON fluorescent probe is developed for the sensing of Cu2+ based on the hydrolysis of a quinoline-2-carboxylate moiety. The probe is weakly fluorescent due to esterification of the phenolic group. Upon treatment with 1 equiv. of Cu2+, the probe exhibits strong fluorescence at 570 nm. The probe also exhibits high selectivity for Cu2+ over other cations with a low detection limit of 0.2 μM, which is sensitive enough to meet the standard of the World Health Organization for Cu2+ in drinking water (30 μM). Moreover, the probe shows a very low cell cytotoxicity, and imaging experiments demonstrate that the probe can be used for the sensing of Cu2+ in living cells.


2018 ◽  
Author(s):  
Suying Xu ◽  
Adam Sedgwick ◽  
Souad Elfecky ◽  
Wenbo Chen ◽  
Ashley Jones ◽  
...  

<p>A boronic acid-based anthracene fluorescent probe was functionalised with an acrylamide unit to incorporate into a hydrogel system for monosaccharide detection<i>. </i>In solution, the fluorescent probe<b> </b>displayed a strong fluorescence turn-on response upon exposure to fructose, and an expected trend in apparent binding constants, as judged by a fluorescence response where D-fructose > D-galactose > D-mannose > D-glucose. The hydrogel incorporating the boronic acid monomer demonstrated the ability to detect monosaccharides by fluorescence with the same overall trend as the monomer in solution with the addition of fructose resulting in a 10-fold enhancement (≤ 0.25 M). <b><u></u></b></p>


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.


2021 ◽  
Author(s):  
Feng Gao ◽  
Xiaolong Tu ◽  
Yongfang Yu ◽  
Yansha Gao ◽  
Jin Zou ◽  
...  

Abstract Herein, an efficient electrochemical sensing platform is proposed for selective and sensitive detection of nitrite on the basis of Cu@C@Zeolitic imidazolate framework-8 (Cu@C@ZIF-8) heterostructure. Core-shell Cu@C@ZIF-8 composite was synthesized by pyrolysis of Cu-metal-organic framework@ZIF-8 (Cu-MOF@ZIF-8) in Ar atmosphere on account of the difference of thermal stability between Cu-MOF and ZIF-8. For the sensing system of Cu@C@ZIF-8, ZIF-8 with proper pore size allows nitrite diffuse through the shell, while big molecules cannot, which ensures high selectivity of the sensor. On the other hand, Cu@C as electrocatalyst promotes the oxidation of nitrite, thereby resulting high sensitivity of the sensor. Accordingly, the Cu@C@ZIF-8 based sensor presents excellent performance for nitrite detection, which achieves a wide linear response range of 0.1 µM to 300.0 µM, and a low limit of detection (LOD) of 0.033 µM. In addition, the Cu@C@ZIF-8 sensor possesses excellent stability and reproducibility, and was employed to quantify nitrite in sausage samples with recoveries of 95.45-104.80%.


2013 ◽  
Vol 295-298 ◽  
pp. 475-478 ◽  
Author(s):  
Zhi Xiang Han ◽  
Ming Hui Du ◽  
Guo Xi Liang ◽  
Xiang Yang Wu

Rhodamine B thiohydrazide (RBS) was firstly employed as turn-on fluorescent probe for hypochlorite in aqueous solution and living cells. It exhibits a stable response to hypochlorite from 1.0×10-6to 1.0×10-5M with a detection limit of 3.3×10-7M. The response of this probe to hypochlorite is fast and highly selective compared with other reactive oxygen species (such as.OH,1O2, H2O2) and other common anions (such as X-, ClO2-, ClO4-, NO3-, NO2-, OH-, Ac-, CO32-, SO42-).


RSC Advances ◽  
2016 ◽  
Vol 6 (21) ◽  
pp. 17059-17063 ◽  
Author(s):  
Yan-Ru Zhang ◽  
Zhi-Min Zhao ◽  
Le Su ◽  
Jun-Ying Miao ◽  
Bao-Xiang Zhao

A ratiometric fluorescent probe CRSH based on a FRET platform for detecting HOCl. CRSH showed high selectivity, excellent sensitivity and a fast response toward HOCl.


RSC Advances ◽  
2017 ◽  
Vol 7 (64) ◽  
pp. 40615-40620 ◽  
Author(s):  
Kui Du ◽  
Shizhen Niu ◽  
Li Qiao ◽  
Yandong Dou ◽  
Qing Zhu ◽  
...  

A simple ratiometric sensor (L1) for the cascade detection of Zn2+ and H2PO4− with high selectivity was reported based on the intermolecular charge transfer (ICT) mechanism.


2016 ◽  
Vol 40 (11) ◽  
pp. 9021-9024 ◽  
Author(s):  
Doo-Hee Lee ◽  
Dong-Nam Lee ◽  
Jong-In Hong

A fluorescent probe showed high selectivity and sensitivity for an organoarsenic blister agent simulant, arsenic trichloride.


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