A Recyclable bi‐functional Luminescent Zinc (II) metal–organic framework as highly selective and sensitive sensing probe for nitroaromatic explosives and Fe 3+ ions

Zn-coordination polymers for fluorescence sensing various contaminants in water

Luminescent coordination polymers (LCPs) have garnered significant attention from researchers as promising materials for detecting contaminants. In this paper, three new LCPs ([Zn(tib)(opda)]n⋅H2O (1), [Zn3(tib)2(mpda)3]n⋅5H2O (2), [Zn (tib)(ppda)]n⋅H2O (3)) with different structures (LCP 1-3: 1D, 2D, 1D) using phenylenediacetic acid isomers and 1,3,5-tris (1-imidazolyl) benzene (tib) are synthesized. The specific surface areas (BET) of LCP 1-3 are 4 m2/g, 19 m2/g, and 13 m2/g respectively. LCP 1-3 exhibit excellent fluorescence properties and can serve as fluorescent probe for the detection of inorganic contaminants and organic contaminants. Due to the large BET of LCP 2, the detection limits for trace analytes surpass those of LCP 1 and 3. The detection limits of LCP 2 for Fe3+, nitrobenzene (NB), chloramphenicol (CAP), and pyrimethanil (PTH) are 8.3 nM, 0.016 μM, 0.19 μM, and 0.032 μM, respectively, and the fluorescence quenching rates are 98.6 %, 98.8 %, 92.3 %, and 98.8 %, respectively. These values outperform most reported in the literature. The quantum yields of LCP 1-3 are 11.84 %, 25.22 %, 22.00 % respectively. Real sample testing of LCP 1-3 reveals favorable performance, where spiked recoveries of LCP 2 for the detection of pyrimethanil in grape skins ranged from 99.62 % to 119.3 % with a relative standard deviation (RSD) of 0.627 % to 4.56 % (n = 3). The fluorescence quenching mechanism was attributed to a combination of photoelectron transfer (PET), resonance energy transfer (RET), and competitive absorption (CA). This study advances the application of LCPs in luminescence sensing and contributes to the expansion of novel materials for detecting environmental pollutants.

Analytical Tools and Methods for Explosive Analysis in Forensics: A Critical Review

This review summarizes (i) compositions and types of improvised explosive devices; (ii) the process of collection, extraction and analysis of explosive evidence encountered in explosive and related cases; (iii) inter-comparison of analytical techniques; (iv) the challenges and prospects of explosive detection technology. The highlights of this study include extensive information regarding the National & International standards specified by USEPA, ASTM, and so on, for explosives detection. The holistic development of analytical tools for explosive analysis ranging from conventional methods to advanced analytical tools is also covered in this article. The most important aspect of this review is to make forensic scientists familiar with the challenges during explosive analysis and the steps to avoid them. The problems during analysis can be analyte-based, that is, interferences due to matrix or added molding/stabilizing agents, trace amount of parent explosives in post-blast samples and many more. Others are techniques-based challenges viz. specificity, selectivity, and sensitivity of the technique. Thus, it has become a primary concern to adopt rapid, field deployable, and highly sensitive techniques.

A Water-Stable Zn-MOF Used as Multiresponsive Luminescent Probe for Sensing Fe3+/Cu2+, Trinitrophenol and Colchicine in Aqueous Medium

A water-stable Zn-MOF was constructed based on H₂PBA and 1, 10-phenanthroline under solvothermal conditions. The compound exhibited a 3D (2,3,8)-connected (4³)₂(4⁶.6⁶.8¹⁵.12)(8) topology framework. The crystal structure and phase purity of the compound was verified by single crystal X-ray diffraction. Subsequently, some studies on the morphology, structure, and luminescent properties were carried out. The results showed that this compound could be used as a versatile chemosensor for Fe³⁺/Cu²⁺, trinitrophenol and colchicine via a luminescence quenching effect in an aqueous medium.

A Stable 3D Zn-Coordination Polymer Sensor Based on Dual Luminescent Ligands for Efficient Detection of Multiple Analytes under Acid or Alkaline Environment

A novel 3D luminescent coordination polymer (LCP) [Zn₄(3-dpyb)₂(odpa)₂(H₂O)₃]·4H₂O (1) (3-dpyb = N,N'-bis (3-pyridinecarboxamide)-1,4-butane, H₄ odpa = 4, 4'-oxidiphthalic acid) was successfully synthesized under solvothermal conditions. LCP 1 displays remarkable fluorescent behavior and stability in a wide range of pH values and different pure organic solvents. More importantly, LCP 1 can become an outstanding candidate in the selective sensing of Fe³⁺, Bi³⁺, Cr₂O₇^2-, MnO₄^-, nitrobenzene (NB), acetaldehyde (AH), and acetylacetone (Hacac) under a lower detection limit. The change process of fluorescent intensity of these seven analytes in a diverse pH range indicates that LCP 1 can be an excellent luminescent sensor in multiple acid/base solutions. As far as we know, it is an infrequent example of a CP-based multiresponsive fluorescent sensor for metal cations, oxyanions, and toxic organic solvents under an acid or alkaline environment.