Rapid determination of vitamin B12 (cobalamin) based on silver nanoclusters capped by polyethyleneimine with different molecular weights and terminal groups

2016 ◽  
Vol 8 (22) ◽  
pp. 4324-4327 ◽  
Author(s):  
Fei Qu ◽  
Qianwei Song ◽  
Jinmao You
Keyword(s):  
Vitamin B12 ◽  
Rapid Determination ◽  
Inner Filter Effect ◽  
Silver Nanoclusters ◽  
Vitamin B ◽  
Molecular Weights ◽  
Filter Effect

Ag nanocluster fluorescence can be dramatically quenched by vitamin B12 by the inner filter effect.

UV-emitting polyelectrolyte-modified MoS2 quantum dots for selective determination of nitrophenol in water samples based on inner filter effect

2020 ◽  
Vol 98 (5) ◽  
pp. 222-227
Author(s):  
Keke Ning ◽  
Guoqiang Xiang ◽  
Cuicui Wang ◽  
Jingxing Wang ◽  
Xiaohong Qiao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Water Samples ◽  
Sodium Molybdate ◽  
Inner Filter Effect ◽  
Pond Water ◽  
Emission Peak ◽  
Selective Determination ◽  
Uv Emission ◽  
Filter Effect

In this work, poly(sodium 4-styrenesulfonate) (PSS) modified molybdenum disulfide quantum dots (MoS2-PSS QDs) were synthesized via a simple hydrothermal method using l-cysteine and anhydrous sodium molybdate as precursors and PSS as a modification reagent, and a selective and sensitive fluorescent sensing method for the determination of p-nitrophenol (p-NP) based on their UV emission was developed. The obtained MoS2-PSS QDs have an obvious UV emission peak (390 nm) with quantum yield of 5.13%. The strong absorption peak of p-NP at 400 nm has large spectral overlap with the UV emission peak (390 nm) of MoS2-PSS QDs. Because of this p-NP absorption, the fluorescence of MoS2-PSS QDs at 390 nm is quenched with the introduction of p-NP via the inner filter effect (IFE) and the decreased fluorescence intensity was linearly proportional to the p-NP concentration in the range of 1–20 μmol/L, leading to a detection limit of 0.13 μmol/L for p-NP. The MoS2 QDs-based fluorescent probe for p-NP is sensitive and selective and was successfully applied in the determination of p-NP in the pond water samples with satisfactory results.

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