Evaluation of Iron Chlorin e6 disappearance and hydrolysis in soil and garlic using salting-out assisted liquid-liquid extraction coupled with high-performance liquid chromatography and ultraviolet-visible detection.

Iron Chlorin e6 (ICE6), a star plant growth regulator (PGR) with independent intellectual property rights in China, has demonstrated its efficacy through numerous field experiments. We innovatively employed salting-out assisted liquid-liquid extraction (SALLE) with HPLC-UV/Vis to detect ICE6 residues in water, soil, garlic seeds, and sprouts. Using methanol and a C18 column with acetonitrile: 0.1% phosphoric acid mobile phase (55:45, v:v), we achieved a low LOQ of 0.43 to 0.77 µg kg-1. Calibration curves showed strong linearity (R2 > 0.992) within 0.01 to 5.00 mg kg-1. Inter-day and intra-day recoveries (0.05 to 0.50 mg kg-1) demonstrated high sensitivity and accuracy (recoveries: 75.36% to 107.86%; RSD: 1.03% to 8.78%). Additionally, density functional theory (DFT) analysis aligned UV/Vis spectra and indicated ICE6's first-order degradation (2.03 to 4.94 days) under various environmental conditions, mainly driven by abiotic degradation. This study enhances understanding of ICE6's environmental behavior, aids in risk assessment, and guides responsible use in agroecosystems.

Adsorption-desorption behavior of florpyrauxifen-benzyl on three microplastics in aqueous environment as well as its mechanism and various influencing factors.

Microplastics (MPs) and pesticides are two categories contaminants with proposed negative impacts to aqueous ecosystems, and adsorption of pesticides on MPs may result in their long-range transport and compound combination effects. Florpyrauxifen-benzyl, a novel pyridine-2-carboxylate auxin herbicide has been widely used to control weeds in paddy field, but the insights of which are extremely limited. Therefore, adsorption and desorption behaviors of florpyrauxifen-benzyl on polyvinyl chloride (PVC), polyethylene (PE) and disposable face masks (DFMs) in five water environment were investigated. The impacts of various environmental factors on adsorption capacity were evaluated, as well as adsorption mechanisms. The results revealed significant variations in adsorption capacity of florpyrauxifen-benzyl on three MPs, with approximately order of DFMs > PE > PVC. The discrepancy can be attributed to differences in structural and physicochemical properties, as evidenced by various characterization analysis. The kinetics and isotherm of florpyrauxifen-benzyl on three MPs were suitable for different models, wherein physical force predominantly governed adsorption process. Thermodynamic analysis revealed that both high and low temperatures weakened PE and DFMs adsorption, whereas temperature exhibited negligible impact on PVC adsorption. The adsorption capacity was significantly influenced by most environmental factors, particularly pH, cations and coexisting herbicide. This study provides valuable insights into the fate of florpyrauxifen-benzyl in presence of MPs, suggesting that PVC, PE and DFMs can serve as carriers of florpyrauxifen-benzyl in aquatic environment.

Hydrolysis of propyrisulfuron in water: Kinetics, influence of 34 environmental factors, transformation products identification, mechanisms and toxicities.

Propyrisulfuron is a novel sulfonylurea herbicide used for controlling annual grass and broad-leaved weeds in fields, but its fates and behaviors in environment are still unknown, which are of utmost importance for environmental protection. To reduce its potential environmental risks in agricultural production, the hydrolysis kinetics, influence of 34 environmental factors including 12 microplastics (MPs), disposable face masks (DFMs) and its different parts, 6 fertilizers, 5 ions, 3 surfactants, a co-existed herbicide of florpyrauxifen-benzy, humic acid and biochar, and the effect of MPs and DFMs on its hydrolysis mechanisms were systematically investigated. The main hydrolysis products (HPs), possible mechanisms, toxicities and potential risks to aquatic organisms were studied. Propyrisulfuron hydrolysis was an acid catalytic pyrolysis, endothermic and spontaneous process driven by the reduction of activation enthalpy, and followed the first-order kinetics. All environmental factors can accelerate propyrisulfuron hydrolysis to varying degrees except humic acid, and different hydrolysis mechanisms occurred in the presence of MPs and DFMs. In addition, 10 possible HPs and 7 possible mechanisms were identified and proposed. ECOSAR prediction and ecotoxicity testing showed that acute toxicity of propyrisulfuron and its HPs for aquatic organisms were low, but may have high chronic toxicity and pose a potential threat to aquatic ecosystems. The investigations are significantly important for elucidating the environmental fates and behaviors of propyrisulfuron, assessing the risks in environmental protection, and further providing guidance for scientific application in agro-ecosystem.

Degradation of a New Herbicide Florpyrauxifen-Benzyl in Water: Kinetics, Various Influencing Factors and Its Reaction Mechanisms.

Florpyrauxifen-benzyl is a novel herbicide used to control weeds in paddy fields. To clarify and evaluate its hydrolytic behavior and safety in water environments, its hydrolytic characteristics were investigated under varying temperatures, pH values, initial mass concentrations and water types, as well as the effects of 40 environmental factors such as microplastics (MPs) and disposable face masks (DFMs). Meanwhile, hydrolytic products were identified by UPLC-QTOF-MS/MS, and its hydrolytic pathways were proposed. The effects of MPs and DFMs on hydrolytic products and pathways were also investigated. The results showed that hydrolysis of florpyrauxifen-benzyl was a spontaneous process driven by endothermic, base catalysis and activation entropy increase and conformed to the first-order kinetics. The temperature had an obvious effect on hydrolysis rate under alkaline condition, the hydrolysis reaction conformed to Arrhenius formula, and activation enthalpy, activation entropy, and Gibbs free energy were negatively correlated with temperature. Most of environmental factors promoted hydrolysis of florpyrauxifen-benzyl, especially the cetyltrimethyl ammonium bromide (CTAB). The hydrolysis mechanism was ester hydrolysis reaction with a main product of florpyrauxifen. The MPs and DFMs did not affect the hydrolytic mechanisms but the hydrolysis rate. The results are crucial for illustrating and assessing the environmental fate and risks of florpyrauxifen-benzyl.

Preparation of a Ti0.7W0.3O2/TiO2 nanocomposite interfacial photocatalyst and its photocatalytic degradation of phenol pollutants in wastewater.

A Ti0.7W0.3O2/TiO2 nanocomposite interfacial photocatalyst was designed and prepared for the photocatalytic degradation of phenol pollutants in wastewater. The detailed properties of the Ti0.7W0.3O2/TiO2 nanocomposite interface (NCI) were analyzed by XRD, SEM, EDX, DRS, UPS and XPS technologies, showing that anatase TiO2 nanospheres (NSs) were uniformly dispersed on the surface of rutile Ti0.7W0.3O2 nanoparticles (NPs) and formed the nanocomposite interface. The DRS and UPS results of 5 wt% Ti0.7W0.3O2/TiO2 NCI indicated a greatly broadened light response range with a wavelength shorter than 527 nm and a shorter band gap energy of 2.37 eV. The conduction band of TiO2 NSs, Ti0.7W0.3O2 NPs and 5 wt% Ti0.7W0.3O2/TiO2 NCI were measured based on the results of the valence band and band gap energy obtained via XPS and DRS, and then the energy level diagram of Ti0.7W0.3O2/TiO2 NCI was proposed. The photocatalytic degradation of phenol at Ti0.7W0.3O2/TiO2 NCI with different loading ratios of Ti0.7W0.3O2 NPs was investigated under optimum conditions (i.e., pH of 4.5, catalyst dosage of 0.45 g L-1 and phenol initial concentration of 95 ppm) under the illumination of ultraviolet visible light. Also, 5 wt% Ti0.7W0.3O2/TiO2 NCI exhibited the highest photocatalytic activity, with the initial rate constant (k) calculated as 0.09111 min-1. After recycling six times, Ti0.7W0.3O2/TiO2 NCI showed good stability and recyclability. The involvement of superoxide radicals in the initial reaction at Ti0.7W0.3O2/TiO2 NCI was evidenced by the use of a terephthalic acid (TA) fluorescent probe. Besides, UV-Vis spectroscopy, UHPLC-MS and GC-MS technologies were used to analyze the main intermediates in the photocatalytic degradation of phenol. The probable photocatalytic degradation mechanism of phenol at Ti0.7W0.3O2/TiO2 NCI was also proposed.

Preparation and evaluation of a novel N-benzyl-phenethylamino-ß-cyclodextrin-bonded chiral stationary phase for HPLC.

A novel N-benzyl-phenethylamino-ß-cyclodextrin-bonded ordered mesoporous SBA-15 chiral stationary phase (BZCDP) for high-performance liquid chromatography (HPLC) was prepared. The structure and morphology of the ligand and the stationary phase were characterized by mass spectrometry, elemental analysis, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. The enantiomers of chiral compounds including nine common ß-adrenergic blocker drugs (ß-blockers), eight dansyl amino acids (DNS-AA) and six flavanones were successfully separated by polar organic solvent and reversed-phase chromatography, respectively. The results showed that BZCDP was a kind of multimode chiral separation materials with an excellent chromatographic performance for the above compounds. In polar organic solvent mode, BZCDP can effectively separate ß-blockers, in which the enantioselectivity factors and resolutions of ß-blockers were up to 1.30 and 1.97 within 20min, respectively. Under the reversed-phase mode, BZCDP exhibited high enantioselectivities for DNS-AA, among them the resolution of dansyl-tyrosine was 3.29 with 20min. BZCDP was also successfully used to separate the flavanone compounds with methanol or acetonitrile as mobile phase. The resolution of 4'-hydroxy flavanone enantiomers reached to 3.65 about 15min. Compared with the native ß-cyclodextrin and γ-cyclodextrin-bonded stationary phases in the literature, the separation speed of BZCDP containing mono-N-benzyl-phenethylamino-ß-cyclodextrin ligand was faster and the separation selectivity was better, which indicated that the N-benzyl-phenethylamino group could also take part in the chiral recognition. After further study, we found that in polar organic solvent mode, the inclusion and hydrogen bonding were the main forces of chiral separations, and in reversed-phase mode, the inclusion and hydrophobic interaction are the main driving forces for chiral separations. Besides excellent chromatographic performance, the home-made cyclodextrin column with mesoporous SBA-15 as the matrix was much cheaper than commercial columns, and good permeability, which can reduce the cost of test and provide fast separation. BZCDP has a good prospect in chiral drug analysis.

[Enantioseparation and determination of atenolol enantiomers in tables on a ß-cyclodextrin-based chiral stationary phase by high performance liquid chromatography].

A novel dinitrophenyl ether ß-cyclodextrin-bonded chiral stationary phase (NESP) for HPLC was prepared with ordered mesoporous SBA-15 as matrix. The fast enantioseparation of atenolol enantiomers on the new stationary phase was achieved through the optimization of mobile phase composition, column temperature and other factors in polar organic solvent mode. The optimized composition of mobile phase was acetonitrile/methanol/glacial acetic acid/triethylamine (90:10:2.5:3.0, v/v/v/v) at the flow rate of 0.5 mL/min. The column tem- perature was set at 20 °C. The detection wavelength was 275 nm. The resolution of atenolol enantiomers was 1.73 with a rather short analysis time, about 20 min, under the above conditions. The atenolol was extracted with methanol from the tablets and analyzed by direct injection for HPLC. A new quantitative method of atenolol enantiomers in tablets was established after the condition optimization. The good linear relationships for two atenolol enantiomers were observed in the range of 2.5-100 mg/L with r of 0. 999 2 and 0. 998 9, respectively. The recoveries of atenolol enantiomers in tablet samples were 94.60%-97.24%. The relative standard deviations (RSDs) of this method were not greater than 0.92% for intra-day and 1.86% for inter-day, respectively. The detection limits (S/N = 3) of concentrations were less than 0.2 mg/L for both enantiomers. The established method is simple and of high selectivity, high recovery and low cost for enantiomer analysis by using homemade cyclodextrin-based chiral column. It has a good application prospect for the fast quality control and the pharmacokinetics study of chiral drugs.

[Separation of purines, pyrimidines, pterins and flavonoids on magnolol-bonded silica gel stationary phase by high performance liquid chromatography].

A new magnolol-bonded silica gel stationary phase (MSP) was used to separate the basic drugs including four purines, eight pyrimidines, four pterins and five flavonoids as polar representative samples by high performance liquid chromatography (HPLC). To clarify the separation mechanism, a commercial ODS column was also tested under the same chromatographic conditions. The high selectivities and fast baseline separations of the above drugs were achieved by using simple mobile phases on MSP. Although there is no end-caped treatment, the peak shapes of basic drugs containing nitrogen such as purines, pyrimidines and pterins were rather symmetrical on MSP, which indicated the the magnolol as ligand with multi-sites could shield the side effect of residual silanol groups on the surface of silica gel. Although somewhat different in the separation resolution, it was found that the elution orders of some drugs were generally similar on both MSP and ODS. The hydrophobic interaction should play a significant role in the separations of the above basic drugs, which was attributed to their reversed-phase property in the nature. However, MSP could provide the additional sites for many polar solutes, which was a rational explanation for the high selectivity of MSP. For example, in the separation of purines, pyrimidines and pterins on MSP, hydrogen-bonding and dipole-dipole interactions played leading roles besides hydrophobic interaction. Some solute molecules (such as mercaptopurine, vitexicarpin) and MSP can form the strong pi-pi stacking in the separation process. All enhanced the retention and improved the separation selectivity of MSP, which facilitated the separation of the basic drugs.