Sensitive Detection Of Picric Acid Research Articles

Synthesis of bridged dinaphthoviologen derivatives for enhanced electrochromic performance and picric acid detection

Electrochromic materials represent a class of highly promising smart materials in contemporary research. Viologen, as a prevalent organic small molecule in smart chromic materials, has garnered extensive attention due to its tunable intermediate structure involving pyridine units and diverse nitrogen atom substituents. In this investigation, the molecular structure of dinaphthoviologen (DNV2+) were modified, and various groups were introduced to ionize nitrogen atoms. This structural modification aimed to decrease the molecular energy gap and enhance the electron acceptability of nitrogen atoms. The results demonstrate robust redox ability in DNV2+. To explore the practical applications, a straightforward DNV2+-based electrochromic device was fabricated, incorporating ferrocene as an electronic supplement. This device exhibited commendable cycling performance (exceeding 1000 cycles) and rapid response times (8 s for coloring and 10 s for fading) without the need for additional electrolytes. Additionally, the transmittance changes by more than 45 %. Moreover, owing to the presence of conjugated structures, DNV2+ exhibited noteworthy fluorescence properties. In fluorescence-based picric acid detection experiments, the synthesized molecules exhibited high selectivity and sensitivity, as evidenced by the determined Stern–Volmer constants (K6b = 2.17 × 104 L/mol, K6c = 3.87 × 104 L/mol). The findings highlight the potential of the developed dinaphthoviologen derivatives for advanced applications in electrochromic devices and sensitive detection of picric acid.

The construction of the flexible covalent organic frameworks with phenyl sulfide as linkers used for adsorping iodine and fluorescence sensing picric acid

The efficient capture of radioactive iodine and sensitive detection of picric acid are very important to environmental protection. Herein, we synthesized two new flexible 4,4′-thiodianiline (TDA)-based covalent organic frameworks (TTDA and HTDA) by using simple Schiff-base polycondensation reactions with flexible 4,4′-thiodianiline (TDA) and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine (TPT − 3 − CHO) and hexa(4-formyl-phenoxy)cyclotriphosphazene (NOP − 6 − CHO). The flexible TDA-based COFs are porous, crystalline, and show high thermal stability and good chemical stability. Due to the high content of heteroatoms, abundant aromatic rings, and orderly network, it is conducive to electron transfer, the as-prepared flexible TDA-based COFs show outstanding dual properties of iodine adsorption and fluorescence sensing. The maximum iodine capacities of TTDA and HTDA are as high as 3.34 and 4.38 g g−1, respectively. The flexible TDA-based COFs can be used for sensing picric acid with low limits of detection (LODs) of 1.25 × 10−9 and 1.67 × 10−9 mol L−1 and high quenching constants (KSV) of 6.00 × 104 and 4.88 × 104 L mol−1, respectively.

A boron-nitrogen heterocyclic AIE probe for sensitive detection of picric acid

This article describes the design and synthesis of a B-N bond-based sensor (BNOH) to detect picric acid (PA), which is easy to synthesize with a high yield. It exhibits aggregation-induced emission (AIE) effect, and its solid bright fluorescence makes it suitable for use as a sensor. As PA sensor, BNOH performs excellently with good selectivity and sensitivity (detection limits as low as 2.9 ppb). The PA response mechanism of BNOH to PA was explored through computational simulation methods. Interestingly, trace amounts of solid PA can be detected by wiping the BNOH paper sensor, achieving convenient and quick PA detection.

A bifunctional 3D porous MOF with potential for fluorescence sensing of picric acid and natural gas purification

A pillared-layer fluorescence metal-organic framework [Zn2(TCPP)(BPE), GXZ-1] has been synthesized by using the AIE ligand 2,3,5,6-tetrakis(4-carboxyphenyl) pyrazine (TCPP) and 1,2-Bis(4-pyridyl) ethylene (BPE). The GXZ-1 exhibited remarkable stability in both air and various solvents. Furthermore, fluorescence experiments demonstrated its potential as a fluorescence probe for the sensitive detection of picric acid (PA). Additionally, the activated GXZ-1 exhibited permanent porosity with a high BET surface area of 210.59 m2 g−1 and a narrow pore size distribution of 0.6 nm. These properties enable GXZ-1 ideally suitable for gas separation applications. Gas adsorption experiments revealed promising CO2/CH4 separation properties, with an IAST adsorption selectivity of 8.37 and 5.39 for equimolar CO2/CH4 gas mixtures at 273/298 K and 1 atm, respectively. In addition, GXZ-1 displayed outstanding chemical and thermal stability, further enhancing its potential for practical applications.

An AIE active imidazole conjugated α-cyanostilbene based sensor for the selective and sensitive detection of picric acid in an aqueous medium

Due to increasing pollution threats, terrorism-sensitive rapid sensing of aromatic nitro explosives (picric acid) has gained predominant significance in environmental safety. Herein, imidazole-derived monofunctional fluorescent sensor 2-(4-aminophenyl)-3-(3-(4,5-diphenyl-1H-imidazol-2-yl)-2-hydroxyphenyl) acrylonitrile (ADHA) was successfully developed for the selective recognition of explosive picric acid. The D-π-A configuration of ADHA facilitates extraordinary photophysical properties with remarkable aggregation-induced emission (AIE). The detection process is induced by the photon-induced electron transfer (PET) and resonance energy transfer (RET) and results in the generation of ADHA+PA complex. The structural relationship and the photophysical properties of ADHA were extensively studied by DFT (Density Functional Theory) methods and spectroscopic analysis. It has been calculated that the detection limit of the formed complex is 6.26 nM. In addition, 1H NMR titrations DFT calculations, and HRMS analysis were performed to understand the detection mechanism better. Test strip-aided detection and invisible ink applications confirmed that ADHA is a versatile sensor for sensitively detecting picric acid without sophisticated instruments. In addition, ADHA was implemented to detect PA in real water samples with remarkable recovery.

A water soluble fluorescent probe for selective and sensitive detection of picric acid – a nitroexplosive

Novel water soluble fluorescent probe for picric acid detection.

3D printed optical sensor for highly sensitive detection of picric acid using perovskite nanocrystals and mechanism of photo-electron transfer

Hand-held, compact and portable sensors for on-site detection of environmental contaminants are in high demand for industry 4.0. Here, we have developed a sensor based on luminescent organic–inorganic metal halide hybrid perovskites nanocrystals (CH3NH3PbBr3) with p-xylylenediamine as an additional capping agent for highly sensitive and selective detection of picric acid (PA), with a good linear range of 1.8 μM–14.3 μM achieving detection of limit (LOD) of 0.3 μM. The electrostatic interaction between PA and the capping ligand of perovskite nanocrystals resulted in significant fluorescence quenching, as revealed by the steady-state and time-resolved spectroscopy. The applicability of the developed sensor for PA detection was validated with a 3D printed device integrating surface mounting device (SMD) and paper microfluidics. This prototype device was successfully applied as a fluorescence turn-off sensor to detect PA, showing great potential for on-site detection. This 3D-printed paper-based microfluidic optical sensor proved very efficient for naked-eye detection of PA with an inbuilt excitation source, avoiding the requirement of expensive and complex instrumentation.

An Ultrasensitive Picric Acid Sensor Based on a Robust 3D Hydrogen-Bonded Organic Framework.

Hydrogen-bonded organic frameworks (HOFs), as a newly developed porous material, have been widely used in various fields. To date, several organic building units (OBUs) with tri-, tetra-, and hexa-carboxylic acid synthons have been applied to synthesize HOFs. To our knowledge, di-carboxylic acids have rarely been reported for the construction of HOFs, in particular, di-carboxylic acid-based HOFs with fluorescence sensing properties have not been reported. In this study, a rare example of a di-carboxylic acid-based, luminescent three-dimensional hydrogen-bonded organic framework has been successfully constructed and structurally characterized; it has a strong electron-rich property originated from its organic linker 9-phenylcarbazole-3,6-dicarboxylic acid. It represents the first example of HOF-based sensors for the highly selective and sensitive detection of PA (Picric acid) with reusability; the LOD is less than 60 nM. This work thus provides a new avenue for the fabrication of fluorescent HOFs sensing towards explosives.

Studies on the characterisation of thiophene substituted 1,3,4-oxadiazole derivative for the highly selective and sensitive detection of picric acid

A novel thiophene substituted 1,3,4-oxadiazole based chemosensor namely 2-(4-(5-(5-hexylthiophen-2-yl) thiophen-2-yl)phenyl) -5-(5-(5-(5-hexylthiophen-2-yl) thiophen-2-yl)thiophen-2-yl)-1,3,4-oxadiazole [TKO] has been characterised for the efficient detection of picric acid (PA) based on fluorescence quenching mechanism. In this regard, the electronic absorption spectra, fluorescence spectra, and fluorescence lifetime of TKO are recorded in the presence of different nitroaromatic compounds (NACs) in ethanol at room temperature. The absorption studies exhibited a blue shift in the absorption maxima with the increase in the concentration of PA. In the fluorescence titration studies, TKO shows a remarkable fluorescence quenching with picric acid as compared to other nitroaromatic compounds. Using the Benesi-Hildebrand plot, the binding constant value of PA with TKO is determined and is of the order of 6.467 × 104 M−1. Job's plot analysis confirms the 1:1 binding stoichiometry ratio between TKO and PA and is supported by the 1H NMR studies. The detection limit is determined and is of the order of 10.08 µM. The competitive studies revealed that TKO is highly selective for recognizing PA without the interference of other NACs. The theoretical studies were also carried out to understand the binding mechanisms of PA with TKO. The fluorescence quenching of TKO by PA may be attributed to photo induced electron transfer (PET). Overall, the experimental findings suggest that, the novel probe TKO may be used as a highly selective and sensitive chemosensor for the detection of explosives like picric acid.

Synthesis of AIEE active triazine based new fluorescent and colorimetric probes: A reversible mechanochromism and sequential detection of picric acid and ciprofloxacin

Two new triazine based multifunctional fluorescent probes T1 and T2 were synthesized that displayed excellent aggregation induced emission enhancement (AIEE) and reversible mechanochromic character. The AIEE active probes were used for selective fluorescence detection of picric acid (PA) based on fluorescence quenching response. The sensitive detection of PA was achieved through electron and charge transfer between them resulting in the formation of the probe–PA complex. The limits of detection of T1 and T2 for PA were calculated as 1.94 and 2.24 nM, respectively. Subsequently, probe–PA complexes acted as fluorescence enhancement base probes for sequential detection of an antibacterial drug, ciprofloxacin (CIP). The sensitivity (detection limit) of the probe–PA complexes for the recognition of ciprofloxacin was determined as 3.16 and 4.46 nM. Hence, a new strategy was successfully developed for the sensing of ciprofloxacin (CIP). The proposed mechanism for the sensing of PA and ciprofloxacin was evaluated through 1H NMR titration, DLS, and DFT analyses. Meanwhile, probes manifested colorimetric identification of PA and CIP. Advantageously, probe–PA complexes were applied in urine samples for the quantification of ciprofloxacin. Moreover, application in real water samples revealed that the spiked recoveries of PA were attained as > 90%. To the best of our knowledge, it is the first report where triazine based fluorescent probes showed excellent simultaneous responses towards force stimuli (mechanochromism), picric acid, and ciprofloxacin.

A Pyrene-Rhodamine FRET couple as a chemosensor for selective detection of picric acid

Selective detection of nitroaromatic compounds such as Picric acid (PA), those being explosive materials and hazardous pollutants of environmental and biological concern is highly desirable. With the operational advantages of the chemosensing approach, a pyrene-rhodamine-B couple (1) was explored in this investigation as a ratiometric molecular probe for selective and sensitive detection of picric acid. The bi-fluorophoric probe displayed absorption and fluorescence enhancements along with colourless to reddish-brown colour transition as signaling responses in the selective presence of PA among all the nitro aromatic analyte investigated. The signaling module relies on PA- mediated modulation of various operational photo-physical processes such as (a) inhibition of photo-induced electron transfer (PET) operative from amino-donor to excited pyrene (b) a conformational translation through spiro-ring opening of rhodamine-B segment, and (c) initiation of Fluorescence Resonance Energy Transfer (FRET) between excited pyrene donor and ring-opened rhodamine acceptor. The ratio of fluorescence from both fluorophores (pyrene and Rhodamine) as output channel displayed sensitive signaling performance (LOD = 13.8 nM) in the detection of PA. The investigation that inferred to the PA-induced selectivity in signalling, higher binding affinity (log Ka≈11), a faster response time, and reversibility in signalling with a counter analyte and an operational pH range established the probe’s efficacy as a chemosensor for PA detection.

Detection of picric acid in industrial effluents using multifunctional green fluorescent B/N-carbon quantum dots

Carbon quantum dots have recently gained widespread attention due to their excellent physicochemical features. The rapid escalation in the dumping of hazardous chemicals into water, spurred demand for developing efficient and selective sensors for toxic chemicals. Herein, we have developed a novel fluorescence sensor for picric acid which is a major pollutant in industrial effluents. The new strategy exploits the development of a fluorescence sensor based on N-doped carbon quantum dots (N-CQDs) followed by boron functionalization. The N-CQDs were synthesized in a rapid single-step microwave technique by employing L-serine and citric acid. Subsequent boron functionalization of N-CQDs was carried out using boric acid for the synthesis of Boron-nitrogen carbon quantum dots (B/N-CQDs). The B/N-CQDs were found to exhibit high quantum yield (24%), good water solubility, outstanding photostability features, and bright green fluorescence under UV light. The morphology of B/N-CQDs is spherical, with scattered particle sizes ranging from 2 to 8 nanometers. Furthermore, B/N-CQDs were found to be an effective fluorescence probe for the selective and sensitive detection of picric acid, with a good linear range of 37 nM-30 µM and a detection limit of 1.8 nM. The Photoluminescence (PL) intensity of B/N-CQDs was selectively quenched by picric acid. The quenching mechanism was conclusively established using fluorescence lifetime decay studies. Moreover, the synthesized B/N-CQDs was successfully employed for the analysis of picric acid from industrial effluents and cell imaging with Hela cells to showcase the utility of the developed fluorescent probe.

Facile preparation of mesoporous silica coated nitrogen doped carbon dots for sensitive detection of picric acid.

In this work, a nanocomposite suitable for long-term storage was constructed for efficient and highly selective detection of picric acid (PA). For this purpose, nitrogen-doped carbon dots (N-CDs) were synthesized by a simple hydrothermal reaction one-step method, and the synthesized nitrogen-doped carbon dots were loaded into amine-modified mesoporous silica nanoparticles (MSN-NH2) to form N-CDs@MSN-NH2 nanocomposites. The as-synthesized N-CDs@MSN-NH2 was detected by X-ray photoelectron spectroscopy (XPS) and the Fourier transform infrared (FT-IR) analysis methods. After being coated with MSNs, the as-synthesized N-CDs@MSN-NH2 exhibits excellent photo-stability in storage for 60 days at room temperature. Furthermore, PA can significantly quench the fluorescence signal of N-CDs@MSN-NH2 through the fluorescence resonance energy transfer (FRET) effect, while other metal ions and nitro compounds only cause little change. The a-synthesized composites were used to detect PA with a detection limit of 50 nM in an aqueous solution. These results indicate that the synthesized composites have promise for application in PA detection in aqueous solution.

Triptycene-based porous photoluminescent polymers with dual role: efficient capture of carbon dioxide and sensitive detection of picric acid

Design and synthesis of unique photoluminescent triptycene-based porous polymers (TBP-OH and TBP-NH2) bearing active functional groups is described herein. Pd catalyzed Sonogashira cross-coupling reaction was utilized to obtain these polymeric networks that are nanoporous and strongly fluorescent in THF. In solid state, these polymers demonstrated CO2 uptake up to 92 mg g−1 at 273 K/1bar and H2 up to 16 mg g−1 at 77 K/1bar which may be attributed to the presence of 3D robust triptycene and CO2-philic groups –OH and –NH2 in their polymeric framework. TBP-OH and TBP-NH2 also selectively capture CO2 over nitrogen and methane. CO2 capture by TBP-OH and TBP-NH2 is a physisorption process and hence reversible in nature. Suspensions of TBP-OH and TBP-NH2 in THF are strongly fluorescent and are also capable of detecting picric acid (an environmental pollutant and explosive) in trace amounts. The Stern–Volmer quenching constants (Ksv) for detection of picric acid (PA) are in the order of 105 M−1.

Sensitive detection of picric acid in an aqueous solution using fluorescent nonconjugated polymer dots as fluorescent probes

Nonconjugated polymer dots (NPDs) were successfully used as fluorescent probes to selectively and sensitively detect picric acid (PA). The NPDs were prepared from polyethylenimine and 1,4-phthalaldehyde under mild conditions and had excitation and emission maxima of 351 and 474 nm, respectively. Fluorescence of the NPDs was efficiently quenched by PA through the inner filter effect because of the overlapping PA absorption band and NPD excitation spectrum. The NPDs allowed PA to be determined with a high degree of sensitivity. The linear range was 0–140 μM and the detection limit was 0.5 μM. The work involved developing a novel method for synthesizing NPDs and a promising platform for determining PA in environmental media.

Preparation of carbon quantum dots/polyaniline nanocomposite: Towards highly sensitive detection of picric acid

Carbon quantum dots/polyaniline (CQDs/PANI) nanocomposite was successfully prepared by in-situ polymerization of aniline. CQDs were synthesized hydrothermally from gelatin with a diameter size of 4.2 nm and a 17% quantum yield. FTIR, UV–vis absorption, fluorescence spectrophotometer, XRD, TEM, XPS and lifetime decay were used to characterize the obtained nanocomposite. The formation of PANI revealed a high quenching effect on CQDs where the TEM images showed that the formed CQDs were greatly embedded in PANI matrix. In this study, CQDs/PANI nanocomposite was used for the detection of picric acid (PA) in the range 0.37–1.42 μM with a low detection limit (LOD) of 0.056 μM. The prepared sensor showed good enhancement and sensitivity towards PA in comparison to pristine CQDs and other nanostructured materials. The mechanism of PA detection has been studied where it was observed that PA is electrostatically interacted to the nanocomposite through – OH group of PA and the protonated PANI salt formed in CQDs/PANI nanocomposite by fluorescence resonance energy transfer applications. The proposed CQDs/PANI sensor was then utilized in real water samples and successfully determined the different amounts of PA spiked into tap water.

Facile and Green synthesis of fluorescent N-doped carbon dots from betel leaves for sensitive detection of Picric acid and Iron ion

In this present work, a facile, green, cost effective route has been applied for the synthesis of water soluble carbon dots from betel leaves by hydrothermal route. As obtained nitrogen doped carbon dots (N-CDs) show remarkable advantages such as water solubility, biocompatibility and excellent stability. It is analyzed by vital characterization techniques such as HR-TEM, AFM, PSA, XRD, XPS, FTIR, UV-–vis and fluorescence spectroscopy with lifetime analysis. It exhibits blue emission under UV lamp (wavelength 365 nm), excitation dependent emission behavior and independent of pH. The obtained N-CDs show excellent response to picric acid (PA) and Fe3+ ions which leads to fluorescence quenching. This phenomenon was applied to design a single probe fluorescence based system for dual detection with high selectivity and sensitivity. A good linear response was obtained between concentration of analyte and fluorescence intensity with limit of detection (LOD) 0.11μM in the range of 0.3−3.3μM for PA and 0.135μM in the range of 0.3−3.3μM for Fe3+. Finally, the obtained fluorescent probe could be a promising tool for sensitive detection of PA and Fe3+ in aqueous solution.

An unprecedented pyridine-based dinuclear mixed-valent ReI/VII oxo-bridged complex: a solvatochromic and AIE-active probe for nanomolar detection of picric acid and trinitrotoluene.

This paper describes the synthesis of an unprecedented oxo-bridged rheniumI/VII (Re) complex by treating Re2(CO)10 with a pyridyl-linked anthracene-based twisted π-conjugated ligand. The molecular structures of both the ligand and the complex are determined by analyzing IR, NMR, and HR-MS spectra and unequivocally determined using single-crystal X-ray diffraction studies. Unlike previous observations, the complexation occurs uniquely to yield an unprecedented oxo-bridged ReI/VII complex. Such a complex is uncommon, and in most cases, Re(vii) appears as the ReO4- counter ion. The aggregation-induced emission (AIE) feature could have been achieved from this conformationally twisted ligand, but the emission of the ligand was quenched in the aggregated state. The complex exhibited solvatofluorochromic properties with a faint emission. The emission intensity significantly (∼6 times) increased in DMF after the addition of a water fraction of 90%, resulting in a bright orange emission. The AIE is mainly caused by restricted intramolecular rotation (RIR) and is supported by the polarity and viscosity effects. The nanoaggregate formation is captured by SEM, and DLS studies were used to determine the average particle size. After the complexation, the ligand becomes more rigid, and the RIR effect becomes prominent facilitating the AIE effect. The electron-rich aggregate's intense orange emission was used for the selective and sensitive detection of picric acid (PA) and 2,4,6-trinitrotoluene (TNT) at nanomolar levels amongst other nitroaromatics through emission quenching. The detailed mechanistic studies reveal the active role of dynamic quenching and complementary photo-induced electron transfer between the probe and TNT or PA. The easy electron transfer process from the electron-rich to the electron-poor system is confirmed by calculating the lowest unoccupied molecular orbital energy of the associated levels. The application is further extended for on-site PA and TNT detection by permeating the probe on a paper and detected at 10-3 M concentration with the naked eye. The PA/TNT detection efficiency is also confirmed by mixing PA or TNT with soil.

Aggregation-directed High Fidelity Sensing of Picric Acid by a Perylenediimide-based Luminogen.

Widespread use of picric acid (PA) in chemical industries and deadly explosives poses dreadful impact on all living creatures as well as the natural environment and has raised global concerns that necessitate the development of fast and efficient sensing platforms. To address this issue, herein, we report a perylenediimide-peptide conjugate, PDI-1, for detection of PA in methanol. The probe displays typical aggregation caused quenching (ACQ) behaviour and exhibits a fluorescence "turn-off" sensory response towards PA which is unaffected by the presence of other interfering nitroaromatic compounds. The sensing mechanism involves PA induced aggregation of the probe into higher order tape like structures which leads to quenching of emission. The probe possesses a low detection limit of 5.6 nM or 1.28 ppb and a significantly high Stern-Volmer constant of 6.87×104 M-1 . It also exhibits conducting properties in the presence of PA vapours and thus represents a prospective candidate for vapour phase detection of PA. This is, to the best of our knowledge, the first example of a perylenediimide based probe that demonstrates extremely specific, selective and sensitive detection of PA and thus grasps the potential for application in practical scenarios.

Construction of zinc(II) coordination polymers based on 3-(3-carboxypropoxy)benzoic acid and N-containing ligands for highly sensitive detection of picric acid

3-(3-Carboxypropoxy)benzoic acid (H2cpba) and its four luminescent Zn(II) coordination polymers with different N-heterocyclic ancillary ligands, namely, [Zn(cpba)(bimb)]n1, [Zn(cpba)(bpy)]n2, [Zn(cpba)(phen)]n3 and [Zn2(cpba)(cdppy)2·5H2O]n4, have been hydrothermally synthesized and fully characterized (bimb = 1,4-bis(imidazol-1-yl-methyl)benzene, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, and Hcdppy = 4-carboxy-2,6-dipyrazin-2-ylpyridine). X-ray single crystal test results showed that complexes 1 and 4 show one-dimensional ladder-like structures, while complexes 2 and 3 are one-dimensional chain structures. These Zn(II) complexes displayed the differences not only in coordination geometries and ligand binding modes but also the luminescent properties in the solid state. Additionally, the luminescence sensing properties revealed that complex 4 can identify picric acid efficiently through fluorescence quenching.