Citrate Capped CdS Quantum Dots as Fluorescence Sensor for Simple and Selective Determination of Metronidazole

Thioglycolic acid (TGA) capped CdS quantum dots (QDs) have been successfully employed as an efficient nano sized fluorescent probe for the selective determination of dopamine (DA) in acetate buffer solution (pH 7).

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

Nanomaterials ◽

10.3390/nano9010032 ◽

2018 ◽

Vol 9 (1) ◽

pp. 32 ◽

Cited By ~ 9

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.

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

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0425 ◽

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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