Development of novel Schiff base fluorophores for selective detection of Cu2+ ions in seawater using test strips

Eco-friendly Fluorescent Sensor for Sensitive and Selective Detection of Zn2+ and Fe3+ Ions: Applications in Human Hair Samples

A new eco-friendly sensor, 3-((6-((4-chlorobenzylidene)amino)pyridin-2-yl)imino)indolin-2-one (CBAPI) was synthesized and well characterized. The CBAPI sensor was employed for detecting Zn2+ and Fe3+ ions. It exhibited a low limit of detection at pH 6.0, with values of 2.90, for Zn2+ and 3.59 nmol L-1 for Fe3+ ions. The sensor demonstrated high selectivity over other interfering cations. Additionally, the high binding constants reflect the great affinity of sensor towards Zn2+ and Fe3+ ions. To further validate its quantification ability for Zn2+ ions, the synthesized CBAPI sensor was used to determine Zn levels in human hair samples, and the results were confirmed using atomic absorption spectroscopy (AAS). The AGREE metric tool was used to assess the method's environmental impact and practical applicability. These positive outcomes indicated that the new method for detecting Zn2+ and Fe3+ ions is environmentally friendly and safe for humans. The developed CBAPI sensor represents a potential development in metal ion detection, combining sensitivity, selectivity, and rapidity.

Recent Development on Copper-Sensor and its Biological Applications: A Review

Metal ion recognition is one of the most prospective research topics in the field of chemical sensors due to its wide range of clinical, biological and environmental applications. In this context, hydrazones are well known compounds that exhibit metal sensing and several biological properties due to the presence of N=CH- bond. Some of the biological properties includes anti-cancer, anti-tumor, anti-oxidant, anti-microbial activities. Hydrazones are also used as a ligand to detect metal ion as well as to generate metal complexes that exhibit medicinal properties. Thus, in recent years, many attempts were made to develop novel ligands with enhanced metal sensing and medicinal properties. In this review, some of the recent development on the hydrazones and their copper complexes are covered from the last few years from 2015-2023. These includes significance of copper ions, synthesis, biological properties, mechanism and metal sensing properties of some of the copper complexes were discussed.

An intelligent smartphone-test strip detection platform for rapid and on-site sensing of benzoyl peroxide in flour samples

Benzoyl peroxide (BPO) is a commonly used flour whitener, but its excessive usage can have adverse effects on human health, such as nutrient loss, vitamin deficiencies and certain diseases. In this study, a europium metal organic framework (Eu-MOF) fluorescence probe was prepared, which exhibited a strong fluorescence emission at 614 nm upon excitation at 320 nm, with a high quantum yield of 8.11%. The red fluorescence of the probe could be effectively quenched by BPO through the inner filter effect (IFE) and photoinduced electron transfer (PET) mechanism. The detection process offered several advantages, including a wide linear range of 0-0.95 mM, a low detection limit of 66 nM and a fast fluorescence response of 2 min. Furthermore, an intelligent detection platform was designed to enhance the practical application of the detection method. This platform combined the portability and visuality of a traditional test strip with the color recognition capability of a smartphone, allowing for the visualization and quantitative detection of BPO in a convenient and user-friendly manner. The detection platform was successfully applied to the analysis of BPO in real flour samples with satisfactory recoveries (99.79%-103.94%), suggesting a promising strategy for the rapid and on-site detection of BPO in food samples.

New nano materials-based optical sensor for application in rapid detection of Fe(II) and Pd(II) ions

For the analytical determination of Fe(II) and Pd(II) concentrations, a novel optical sensor based on spectrophotometric technique was used. The optical sensor was prepared by direct immobilization of a novel synthesized chromophore, 5-amino-phenanthrolin-3 formyl salicylic acid, onto nanocellulose. Human vision can identify the color associated with Fe II ions, and spectrophotometric methods can measure it with detection and quantification limits of 0.239 and 0.796 ppb, respectively. Pd(II) detection and quantification limits were 0.318 ppb and 1.06 ppb, respectively. The effects of various parameters on the detection of Fe(II) or Pd(II) ion content were investigated and optimized. The optical phenanthroline-nanocellulose (5-Phen) sensor could be reproduced multiple times and used with a higher capacity each time. The results demonstrated that the 5-Phen sensor could measure Fe(II) in human blood serum accurately and successfully even without any pre-concentration.

Study on the Performance of Composite Adsorption of Cu2+ by Chitosan/β-Cyclodextrin Cross-Linked Zeolite

In order to remove Cu2+ from wastewater, a kind of microsphere adsorbent (SCDO) with high efficiency for Cu2+ adsorption was prepared by the microdrop condensation method, where chitosan (CTS) and sodium alginate (SA) were used as the matrix to crosslink β-cyclodextrin (β-CD) and zeolite (Zeo). The structure and properties of SCDO were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Upon that, the adsorption performance of SCDO for Cu2+ was studied, in which the effects of pH, initial concentration, dosage, adsorption time and temperature were investigated. The results showed that the removal rate of Cu2+ reached 97.08%, and the maximum adsorption capacity was 24.32 mg/g with the temperature at 30 °C, the dosage of SCDO at 12 g/L, the initial concentration of Cu2+ at 100 mg/L, the pH of the solution at 6.0 and the adsorption time at 120 min, respectively. The adsorption process of Cu2+ by SCDO occurred in accordance with quasi-second-order kinetics model and Langmuir adsorption isotherm. After four repeats of continuous adsorption and desorption, the regenerative removal rate of Cu2+ could still reach 84.28%, which indicated that SCDO had outstanding reusability.