A functional cobalt-organic framework constructed by triphenylamine tricarboxylate: Detect nitroaromatics by fluorescence sensing and UV-shielding

Efficient smart-phone luminescent sensing detection based on new multifunctional Cd(II) luminescent coordination polymers

Based on the mixed ligand strategy, two new isostructural CdII coordination polymers: {[Cd3(tcpa)2(bima)(DMF)]‧3DMF} (CP 1), {[Cd3(tcpa)2(bmima)(DMF)]‧3DMF} (CP 2) were synthesized by combining two flexible anthracene-based and a triphenylamine-based ligands with large π-electron-rich structure using a solvothermal method (H3tcpa = tris(4-carboxyphenyl)amine; bima = 9,10-bis(1H-imidazole-1-yl)methyl)anthracene and bmima = 9,10-bis((2-methyl-1H-imidazol-1-yl)methyl)anthracene). CP 1 and CP 2 show an unreported new 3D (3,14)-c net structure with the {430·648·813}{43}4 topology. Both CPs could detect Cr2O72-, Nitroaromatic explosives 2,4,6-Trinitrophenol (TNP) and 2,4-dinitrophenol (DNP) through rapid fluorescence quenching response with high quenching efficiency Ksv and low LOD with 0.19 μM (Cr2O72-), 0.54 μM (TNP), 0.76 μM (DNP) for CP 1 and 0.28 μM (Cr2O72-), 0.23 μM (TNP), 0.65 μM (DNP) for CP 2, respectively. In addition, the mechanism of quenching Cr2O72-, TNP and DNP by CPs is proposed through experimental research and theoretical simulation. The quenching of Cr2O72- by CPs is mainly competitive absorption (CA), while the quenching of TNP/DNP is achieved through the coexistence of competitive absorption CA, photo induced electron transfer (PET) and fluorescence resonance energy transfer (FRET). Moreover, we have been developed a portable smartphone-assisted on-site detection platform, which can perform semi-quantitative analysis of Cr2O72- acconding to fluorescence color changes. This work constructed a ratiometric sensing platform for quickly and conveniently detection of Cr2O72-, TNP and DNP pollutants.

Sensitive and reliable hybrid nanosensor (Co2+-CDs@R-CDs) for ratiometric fluorescent and colorimetric detecting NO2. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024;321:124661. [PMID: 38909562 DOI: 10.1016/j.saa.2024.124661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

A ratiometric fluorescent and colorimetric detecting assay for NO2- was realized by a hybrid nanosensor (Co2+-CDs@R-CDs) utilizing firstly through the redox reaction of nitrite (NO2-) with Co2+, of which the hybrid nanosensor Co2+-CDs@R-CDs was fabricated by Co2+-doped carbon dots (Co2+-CDs) and a reference of red-emitting carbon dots (R-CDs). The ratiometric fluorescent linear detection range of NO2- was 2.5-45 μM and the limit of detection (LOD) was 0.068 μM with the response time of 120 s. While, the colorimetric linear detection range of NO2- was 2.5-60 μM and the LOD was 0.075 μM. In addition, a portable smartphone system which could measure the R (red), G (green), and B (blue) values of the fluorescence and the visible color of the coated Co2+-CDs@R-CDs paper strip-based sensor had also been developed and successfully applied to detect NO2- in sausage, pickles and tap water samples.

Development of a three-dimensional porous ionic liquid-chitosan-graphene oxide aerogel for efficient extraction and detection of polyhalogenated carbazoles in sediment samples

The three-dimensional porous ionic liquid-chitosan-graphene oxide aerogel (IL-CS-GOA) monolithic adsorbent with a through-hole structure was prepared using natural chitosan (CS) as the skeletal framework, graphene oxide (GO) as the support to provide mechanical strength, and ionic liquid (IL) as the porogen and modifier. The resulting IL-CS-GOA demonstrated a fluffy and porous structure with various pore sizes and excellent regeneration capability (over six cycles). Its specific surface area exceeded that of CS-GOA and IL-GOA by more than 7 times, enhancing its polyhalogenated carbazoles (PHCZs) adsorption capacity. Within 5 min, IL-CS-GOA (1.0 mg) exhibited adsorption amounts of 539 ng mg-1 for 3-bromocarbazole (3-BCZ), 716 ng mg-1 for 2,7-dibromocarbazole (2,7-BCZ), and 798 ng mg-1 for 1,3,6,8-tetrabromocarbazole (1,3,6,8-BCZ), showcasing its rapid mass transfer and high adsorption capabilities. IL-CS-GOA was utilized as the adsorbent for glass dropper extraction (GDE) in conjunction with gas chromatography-mass spectrometry (GC-MS/MS), to develop a highly efficient and accurate method for determining PHCZs in sediments. Under optimal conditions, the established method exhibited a wide linear range (0.4-250 ng g-1, r ≥ 0.9990), low detection limits (0.04-0.24 ng g-1), and satisfactory recoveries (80.5 %-93.8 %), enabling the accurate and rapid detection of PHCZs in sediment samples. This study presents a novel approach for creating three-dimensional porous aerogels, introduces a new form of sample pretreatment using GDE with a monolithic adsorbent, and offers a new method for the determination of PHCZs in environmental matrices.

Co-MOF@MWCNTs/GCE for the sensitive detection of TBHQ in food samples

tert-Butylhydroquinone (TBHQ) is a novel synthetic antioxidant with a higher safety profile and antioxidant effect that is more excellent than other synthetic antioxidants and is internationally recognized as one of the best food antioxidants. However, its excessive use in food can have unfavorable effects on the human body. Thus, it is critical to establish a rapid method for the detection of TBHQ in food samples. In this study, a cobalt-based metal-organic framework (Co-MOF) was fabricated by a one-pot hydrothermal method and embedded in multi-walled carbon nanotubes (MWCNTs) to construct an economical and sensitive electrochemical sensor for TBHQ. The results showed that this sensor possessed a wide linear range (0.004-20 μM and 20-300 μM), a low limit of detection (LOD = 2.5 nM, S/N = 3) as well as an ultra-high sensitivity (43.19 μA μM-1 cm-2). Moreover, the sensor also has superior selectivity, repeatability, reproducibility and anti-interference ability and can be successfully applied for the detection of TBHQ in samples of instant noodles and potato chips.