scholarly journals Ammonium Pyrrolidine Dithiocarbamate-Modified CdTe/CdS Quantum Dots as a Turn-on Fluorescent Sensor for Detection of Trace Cadmium Ions

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 312
Author(s):  
Yuan Yin ◽  
Qingliang Yang ◽  
Gang Liu
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Pyrrolidine Dithiocarbamate ◽  
Optimal Conditions ◽  
Cds Quantum Dots ◽  
Cadmium Ions ◽  
Turn On ◽  
Ammonium Pyrrolidine Dithiocarbamate ◽  
Trace Cadmium

In this work, ammonium pyrrolidine dithiocarbamate (APDC) was used as a surface etchant to modify CdTe/CdS core-shell quantum dots (QDs). The APDC etchant combines with the cadmium ions (Cd2+) on the surface of the QDs, resulting in the formation of surface holes. The formation of these holes changes the QD surface structure, which leads to fluorescence quenching of the QDs. Newly added Cd2+ can selectively recognize and combine with these holes; thus, the fluorescence intensity of the QDs can be restored. The linear response of this turn-on fluorescent sensor was found to be 0–100 μg/L and 100–600 μg/L under the determined optimal conditions, and its limit of detection (LOD) for Cd2+ was 2.642 μg/L (23.5 nmol/L).

scholarly journals Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 32 ◽  
Author(s):  
Zhezhe Wang ◽  
Xuechun Xiao ◽  
Tong Zou ◽  
Yue Yang ◽  
Xinxin Xing ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Citric Acid ◽  
Limit Of Detection ◽  
Copper Ions ◽  
High Sensitivity ◽  
Fluorescence Sensor ◽  
Cds Quantum Dots ◽  
Detection Range ◽  
Cds Qds

Citric acid capped CdS quantum dots (CA-CdS QDs), a new assembled fluorescent probe for copper ions (Cu2+), was synthesized successfully by a simple hydrothermal method. In this work, the fluorescence sensor for the detection of heavy and transition metal (HTM) ions has been extensively studied in aqueous solution. The results of the present study indicate that the obtained CA-CdS QDs could detect Cu2+ with high sensitivity and selectivity. It found that the existence of Cu2+ has a significant fluorescence quenching with a large red shifted (from greenish-yellow to yellowish-orange), but not in the presence of 17 other HTM ions. As a result, Cu2S, the energy level below the CdS conduction band, could be formed at the surface of the CA-CdS QDs and leads to the quenching of fluorescence of CA-CdS QDs. Under optimal conditions, the copper ions detection range using the synthesized fluorescence sensor was 1.0 × 10‒8 M to 5.0 × 10‒5 M and the limit of detection (LOD) is 9.2 × 10‒9 M. Besides, the as-synthesized CA-CdS QDs sensor exhibited good selectivity toward Cu2+ relative to other common metal ions. Thus, the CA-CdS QDs has potential applications for detecting Cu2+ in real water samples.

A turn-on fluorescent sensor for zinc and cadmium ions based on perylene tetracarboxylic diimide

The Analyst ◽  
2013 ◽  
Vol 138 (3) ◽  
pp. 901-906 ◽  
Author(s):  
Xiangjun Liu ◽  
Nan Zhang ◽  
Jin Zhou ◽  
Tianjun Chang ◽  
Canliang Fang ◽  
...  
Keyword(s):  
Fluorescent Sensor ◽  
Cadmium Ions ◽  
Turn On

para-Hydroxy Thiophenol-Coated CdSe/ZnS Quantum Dots as a Turn-On Fluorescent Probe for H2O2 Detection in Aqueous Media

2018 ◽  
Vol 71 (12) ◽  
pp. 971 ◽  
Author(s):  
Xiaomei Wang ◽  
Yong Luo ◽  
Hu Xu ◽  
Dan Li ◽  
Yuhong Wang
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Hydroxy Ketone ◽  
Hole Transfer ◽  
Turn On ◽  
H2o2 Detection ◽  
Potential Alternative ◽  
Fluorescence Turn On ◽  
Optimized Conditions

Since hydrogen peroxide plays an important role in various fields, a facile, simple, highly selective, and stable analytic method for H2O2 is desirable. Semiconductor quantum dots (QDs) have acted as a potential alternative for organic fluorophores in fluorescence analytical fields due to their superior optical properties. Herein, we report hydrophilic p-hydroxy thiophenol (p-HTP) coated CdSe/ZnS QDs (denoted as p-HTP-QDs) acting as a selective fluorescence ‘turn-on’ probe for H2O2 in aqueous media. The obtained p-HTP-QD probe exhibits weak fluorescence, which stems from hole transfer from the QDs to p-HTP. The presence of H2O2 induces an oxidative structural transformation of p-HTP in p-HTP-QDs from a phenol structure to an α-hydroxy ketone derivative, which extremely reduces the driving force for hole transfer. Thus, the QDs photoluminescence (PL) was re-switched on. Under optimized conditions, an excellent linear relationship between fluorescence response and H2O2 concentration could be produced with a linear range from 0.309 to 4.900mM. The limit of detection of this probe was found to be 0.135mM. Moreover, the present probe exhibited a high selectivity of H2O2 over other reactive oxygen species/reactive nitrogen species (ROS/RNS) and was successfully used in the detection of H2O2 in real water samples.

scholarly journals Surface-modified Colloid CdTe/CdS Quantum Dots by a Biocompatible Thiazolidine Derivative as Promising Platform for Immobilization of Glucose Oxidase: Application to Fluorescence Sensing of Glucose

2021 ◽  
Author(s):  
Rahman Hallaj ◽  
Zahra Hosseinchi
Keyword(s):  
Quantum Dots ◽  
Glucose Oxidase ◽  
Limit Of Detection ◽  
Low Cost ◽  
Fluorescence Emission ◽  
Cds Quantum Dots ◽  
Fluorescence Sensing ◽  
Experimental Conditions ◽  
Glucose Determination ◽  
Cds Qds

Abstract This work focuses on the synthesis of novel modified core-shell CdTe/CdS quantum dots (QDs) and develops as a fluorescence sensor for glucose determination. The (E)-2,2'-(4,4'-dioxo-2,2'-dithioxo-2H,2'H-[5,5'-bithiazolylidene]-3,3'(4H,4'H)-diyl)bis(3- mercaptopropanoic acid) (DTM) as a new derivative of thiazolidine was synthesized and characterized and used to surface-modification of CdTe/CdS QDs. DTM-capped CdTe/CdS QDs used to immobilization of glucose oxidase (GOD). The intensity fluorescence emission of the CdSe/CdS-DTM/GOD is highly sensitive to the concentration of H2O2 as a byproduct of the catalytic oxidation of glucose. The experimental results showed that the quenched fluorescence was proportional to the glucose concentration within the range of 10 nM − 0.32 µM under optimized experimental conditions. The limit of detection of this system was found to be 4.3 nM. Compared with most of the existing methods, this newly developed system possesses many advantages, including simplicity, low cost, and good sensitivity.

A Mn:ZnSe quantum dot-based turn-on fluorescent sensor for the highly selective and sensitive detection of Cd2+

2020 ◽  
Vol 12 (4) ◽  
pp. 552-556 ◽  
Author(s):  
Zhi-Qiang Zhou ◽  
Li-Yun Yang ◽  
Yuan-Ping Liao ◽  
Hui-Yan Wu ◽  
Xiao-Hui Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Fluorescent Sensor ◽  
Sensitive Detection ◽  
Sensing Properties ◽  
Turn On ◽  
Fluorescence Turn On

A highly selective and sensitive nanoprobe with fluorescence turn-on sensing properties for recognizing Cd2+ was developed through replacing Mn2+ near the surface of Mn:ZnSe quantum dots.

Simple strategy to enhance the sensitivity of fluorescent sensor-based CdS quantum dots by a surfactant for Hg2+ detection

2021 ◽  
Author(s):  
Pradthana Sianglam ◽  
Kessarin Ngamdee ◽  
Phattananawee Nalaoh ◽  
Vinich Promarak ◽  
Andrew J. Hunt ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fluorescent Sensor ◽  
Detection Sensitivity ◽  
Cds Quantum Dots ◽  
Mercury Ions ◽  
Simple Strategy ◽  
Cds Qds

A simple strategy to enhance the detection sensitivity of fluorescent sensor-based CdS quantum dots (CdS QDs) for the detection of mercury ions (Hg2+) was demonstrated. L-Cysteine-capped CdS QDs (L-Cyst-CdS QDs)...

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