Composite Material Based on Carbon Dots and Molecularly Imprinted Polymers: A Facile Probe for Fluorescent Detection of 4-Nitrophenol

A new fluorescence composite material for the sensitive and selective determination of 4-nitrophenol (4-NP) was developed based on molecularly imprinted polymers (MIPs) incorporated with carbon dots (CDs). First, fluorescent CDs with a high quantum yield (QY) of 51.8% were prepared by hydrothermal synthesis method by using anhydrous citric acid as carbon source and AEAPMS as surface modifier. Then, CDs were fabricated with MIPs (CDs@MIPs) by sol–gel method using 4-NP as template, (3-aminopropyl) triethoxysilane (APTES) as functional monomer, tetraethoxysilane (TEOS) as cross-linker and CDs as signal sources, respectively. The CDs@MIPs exhibited strong fluorescence property and high selectivity to 4-NP as it incorporated merits of CDs and MIPs. Under optimized conditions, the relative fluorescence intensity of CDs@MIPs decreased linearly with the concentration of 4-NP from 0.025[Formula: see text][Formula: see text]g[Formula: see text]mL[Formula: see text] to 5[Formula: see text][Formula: see text]g[Formula: see text]mL[Formula: see text]. The limit of detection (LOD) of 4-NP was 5[Formula: see text]ng[Formula: see text]mL[Formula: see text] (35[Formula: see text]nM). Specificity and selectivity experiments showed that CDs@MIPs can selectively detect 4-NP with rare interference of other competitive analogs and metal ions. Finally, CDs@MIPs was successfully used to detect 4-NP in river water samples with the recoveries ranging from 94.0% to 103.4%. The results demonstrated that the prepared CDs@MIPs can be applied to the selective and sensitive detection of trace 4-NP in real samples.

Download Full-text

Fluorescent Nanosensor based on Molecularly Imprinted Polymers Coated on Graphene Quantum Dots for Fast Detection of Antibiotics

10.20944/preprints201807.0281.v1 ◽

2018 ◽

Author(s):

Tongchang Zhou ◽

Arnab Halder ◽

Yi Sun

Keyword(s):

Quantum Dots ◽

Fluorescence Intensity ◽

Molecularly Imprinted Polymers ◽

Limit Of Detection ◽

Sol Gel ◽

Graphene Quantum Dots ◽

Carboxyl Groups ◽

One Pot ◽

Molecularly Imprinted ◽

Imprinted Polymers

In this work, we firstly explored a mild, clean, and highly efficient approach for the synthesis of graphene quantum dots (GQDs). GQDs with carboxyl groups or amino groups, were prepared from one-pot environmentally friendly method assisted by hydrogen peroxide, respectively. It was proved that carboxyl groups played an important role in the fluorescence quenching. Based on these findings, we developed a novel fluorescent nanosensor by combining molecularly imprinted polymers (MIPs) with carboxyl functionalized GQDs for the determination of tetracycline (TC) in aqueous samples. The nanocomposite was prepared using a sol-gel process. GQDs-MIPs showed strong ﬂuorescent emission at 410 nm when excited at 360 nm, which was subsequently quenched in the presence of TC. Under optimum conditions, the fluorescence intensity of GQDs-MIPs decreased in response to the increase of TC concentration with good linearity rage of 1.0-104 µg L-1. The limit of detection was determined to be 1 µg L-1. The fluorescence intensity of GQDs-MIPs was more strongly quenched by TC compared to the corresponding non-imprinted polymers, GQDs-NIPs. With the high sensitivity, the material was also successfully worked for the detection of TC in real spiked milk samples.

Download Full-text

Fluorescent Nanosensor Based on Molecularly Imprinted Polymers Coated on Graphene Quantum Dots for Fast Detection of Antibiotics

Biosensors ◽

10.3390/bios8030082 ◽

2018 ◽

Vol 8 (3) ◽

pp. 82 ◽

Cited By ~ 11

Author(s):

Tongchang Zhou ◽

Arnab Halder ◽

Yi Sun

Keyword(s):

Quantum Dots ◽

Molecularly Imprinted Polymers ◽

Limit Of Detection ◽

Fluorescent Sensor ◽

Sol Gel ◽

Graphene Quantum Dots ◽

Carboxyl Groups ◽

One Pot ◽

Molecularly Imprinted ◽

Imprinted Polymers

In this work, we developed a novel fluorescent sensor by combining molecularly imprinted polymers (MIPs) with graphene quantum dots (GQDs) for the determination of tetracycline (TC) in aqueous samples. Firstly, we developed a one-pot green method to synthesize GQDs as the fluorescent probes. GQDs with carboxyl groups or amino groups were fabricated. It was found that carboxyl groups played an important role in the fluorescence quenching. Based on these findings, the GQDs-MIPs microspheres were prepared using a sol-gel process. GQDs-MIPs showed strong fluorescent emission at 410 nm when excited at 360 nm, and the fluorescence was quenched in the presence of TC. Under optimum conditions, the fluorescence intensity of GQDs-MIPs decreased in response to the increase of TC concentration. The linear rage was from 1.0 to 104 µg·L−1, and the limit of detection was determined to be 1 µg·L−1. The GQDs-MIPs also demonstrated high selectivity towards TC. The fluorescent sensor was successfully applied for the detection of TC in real spiked milk samples.

Download Full-text