Flexible Electrochemical Platform Coupled with In Situ Prepared Synthetic Receptors for Sensitive Detection of Bisphenol A

A flexible electrochemical sensor based on the carbon felt (CF) functionalized with Bisphenol A (BPA) synthetic receptors was developed. The artificial Bisphenol A receptors were grafted on the CF by a simple thermal polymerization molecular imprinting process. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and electrochemical characterizations were used to analyze the receptors. Characterization results demonstrated that the Bisphenol A synthetic receptors successfully formed on the CFs surface. Because the synthetic receptor and the porous CFs were successfully combined, the sensor displayed a better current response once Bisphenol A was identified. The sensor's linear range was determined to be from 0.5 to 8.0 nM and 10.0 to 300.0 nM, with a detection limit of 0.36 nM. Even after being bent and stretched repeatedly, the electrode's performance was unaffected, demonstrating the robustness, adaptability and viability of installing the sensor on flat or curved surfaces for on-site detection. The designed electrochemical sensor has been used successfully to identify Bisphenol A in milk samples with satisfactory results. This work provided a promising platform for the design of implantable, portable and miniaturized sensors.

A Critical Review of Analytical Applications of Chitosan as a Sustainable Chemical with Functions Galore

Biomass and biowastes stand as sustainable and cost-effective environmentally benign alternative feedstock. Chitosan is a biocompatible, bioactive, and biodegradable biopolymer derived from chitin to achieve eight aspects out of the 12 green chemistry principles. Chitosan got significant attention in several fields including chemical analysis, in addition to chemical functionally, which enabled its use as adsorbent and its structural crosslinking using various crosslinkers. The physicochemical, technological, and optical properties of chitosan have been extensively exploited in analysis. Mainly, deacetylation degree and molecular weight are controlling its properties and hence controlling its functions. This review presents a structure, properties, and functions relationships of chitosan. It also aims to provide an overview of the different functions that chitosan can serve in each analytical technique such as supporting matrix, catalyst…etc. The contribution of chitosan in improving the ecological performance is discussed in each technique.

A novel fluorescent molecularly imprinted polymer SiO2 @CdTe QDs@MIP for paraquat detection and adsorption

Paraquat (PQ) residue is harmful for human health, agriculture, and the aquatic environment. This paper proposes a novel fluorescent molecularly imprinted polymer (MIP), SiO₂ @CdTe QDs@MIP, for PQ detection and adsorption. The MIP was synthesized using 3-aminopropyltriethoxysilane as the functional monomer, 4,4'-bipyridyl as the template molecule, and tetraethoxysilane as the cross-linker. In addition, CdTe quantum dots featuring unique optical characteristics and excellent photochemical stability were combined as signal reporter. The synthesized MIP had a Brunauer-Emmett-Teller surface area of 68.2 m² /g, pore volume of 0.42 cm³ /g and pore size of 6.9 nm, demonstrating the potential for both PQ detection and adsorption. For PQ detection, the MIP could achieve three orders of magnitude better than the limit of detection, and one order of magnitude wider detection range than existing methods. The PQ recovery values for real samples of water and corn were 96.4-102.1% and 93.9-97.3%, respectively. The amount of PQ detected by the MIP was within 98.05% on average of that using high-performance liquid chromatography. For PQ adsorption, the MIP had an adsorption capacity of 3.36 mg/g, and followed a pseudo-second-order kinetic model with excellent toxicological characteristics. Overall, the novel SiO₂ @CdTe QDs@MIP proposed in this paper could facilitate an efficient and convenient method for PQ detection and adsorption.

A novel fluorescent functional monomer as the recognition element in core–shell imprinted sensors responding to concentration of 2,4,6-trichlorophenol

We have demonstrated a fluorescent functional monomer instead of the traditional functional monomers for molecularly imprinted sensors. The sensors were firstly used to selectively detect 2,4,6-trichlorophenol (2,4,6-TCP) by solid fluorescence detection without a dispersion solution. Moreover, the selectivity and anti-interference ability of the SiO₂@dye-FMIPs sensor meet the requirements of a fluorescent sensor. The novel fluorescent monomer introduced into MIP is no longer just a fluorophore without recognizing ability. The fluorescence intensity of SiO₂@dye-FMIPs showed a linear response to 2,4,6-TCP concentration in the range of 0–100 nM with a detection limit of 0.0534 nM. We could also demonstrate that such a system can not only get rid of the confines of traditional functional monomers and detection manner, but also improved the applications of MIPs sensors in sensing systems.

We have demonstrated a molecularly imprinted sensor with a fluorescent functional monomer instead of the traditional functional monomers to detect 2,4,6-TCP.

Specific oriented recognition of a new stable ICTX@Mfa with retrievability for selective photocatalytic degrading of ciprofloxacin

A new imprinted photocatalyst ICTX@Mfa which exhibits superior specific oriented recognition capability, stability and retrievability for selectively degrading ciprofloxacin.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Ultrasensitive detection of bisphenol A in aqueous media using photoresponsive surface molecular imprinting polymer microspheres

A photoresponsive SMIP was prepared for photocontrolled detection of trace bisphenol A in aqueous media with simplicity and good efficiency.