Determination of flumioxazin residue in food samples through a sensitive fluorescent sensor based on click chemistry

Novel fluorescence approach for trace quantification of levonorgestrel in breast milk based on click reaction with benzonitrofurazan azide (NBD-AZ)

Although the great importance of oral contraceptive agents in birth control, their existence in breast milk became a cause for concern, since infant exposure to these hormones is associated with many health problems. Consequentially, developing a sensitive bioanalytical method for monitoring their concentrations in breast milk is an urgent demand to examine the safety or the risk of these compounds on infants. Levonorgestrel is one of the most common contraceptive hormones under concern. Despite the high sensitivity of the fluorometric methods, detection of Levonorgestrel by them is confined because its structure does not exhibit any fluorescence. For the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole to react with the alkyne group of Levonorgestrel, to give a highly fluorescent triazole derivative that exhibited strong signal at wavelength of 544 nm after excitation at 470 nm. Reaction parameters impacting the fluorescence were cautiously studied and optimized. The suggested approach has been successfully applied in Levonorgestrel estimation in breast milk samples with linearity of (0.4-80 ng.ml-1) and low detection limit of 0.12 ng.ml-1without interferences from any biological components and with mean % recovery of 97.84 ± 2.73. Accuracy, sensitivity, selectivity, simplicity, and low-cost makes this approach a convincing, promising, and appealing alternative over reported analytical methods for Levonorgestrel bioanalysis in different matrices.

Non-biological fluorescent chemosensors for pesticides detection

The ongoing poisoning of agricultural products has pushed the security problem to become an important issue. Among them, exceeding the standard rate of pesticide residues is the main factor influencing the quality and security of agricultural products. Moreover, the abuse of pesticides has introduced a large amount of residues in soil and drinking water, which will enter the food chain to the human body, leading to neurological disorders and cancer. Therefore, great efforts have been devoted to developing fluorescent sensors for detecting pesticide in a facile, quickly, sensitive, selective, accurate manner, which exhibit greater advantages than some traditional methods. In this review, we mainly focus on summarizing the non-biological fluorescent probes for organic pesticides detection with the detection limit of micromole to nanomole, including organic functional small molecules, calixarenes and pillararenes, metal organic framework systems, and nanomaterials. Meanwhile, we described the different sensing mechanisms for pesticides detection of these mentioned fluorescent sensors, the detection limit of each pesticide, the application in detecting actual samples, as well as their respective advantages and development prospects associated with present non-biological fluorescent sensors.

Photocatalytic Applications of Fe–Ag Co-Doped TiO2 Nanoparticles in Removal of Flumioxazin Pesticide Residues in Water

Fe–Ag co-doped TiO2 nanoparticles (NPs) were prepared as a photocatalyst using a precipitation method for the removal of flumioxazin pesticide residues in water. The analytical method was validated with specificity, linearity, recovery, precision, the limit of quantification, and detection limit. Linearity was determined by different known concentrations of standard solutions. Detection limit was identified as the lowest concentration resulting in a 3-fold response to baseline noise. Photolytic and photocatalytic studies were conducted in borosil glass bottles under sunlight at a single fortification level (1.0 μg/mL) in Milli-Q water with various pH values (pH 4.0, 7.0, and 9.0). The optimum catalyst concentration recommended for complete degradation was found to be 50 mg/L under sunlight. The HPLC-UV method was used to determine flumioxazin residues in water, and the rate constant, DT50, and DT90 values were calculated from the data obtained. The photolytic results do not indicate a significant residue loss due to adsorption. Fe–Ag co-doped TiO2 NPs are an outstanding decontaminating catalyst in various water samples.

A novel carbon quantum dot-based fluorescent nanosensor for selective detection of flumioxazin in real samples

Herein, a carbon quantum dot-based highly selective luminescent probe has been designed for the detection of the pesticide flumioxazinviathe alkyne azide click reaction.

Quantification of DNA through a fluorescence biosensor based on click chemistry

A simple, sensitive and selective fluorescence biosensor for determination of DNA using CuS particles based on click chemistry is reported.