Detection Of Picric Acid Research Articles

Precision picric acid detection via a fluorenone-amide functionalized fluorescent micellar probe

Detection of picric acid (PA) in aqueous solutions is crucial for pollution control, extending beyond national security and military applications. Herein, a binary ensemble AM@SDS has been assembled by encapsulating a fluorenone functionalized amide-based probe (AM) within the micelles of an anionic surfactant, sodium dodecyl sulphate (SDS) in an aqueous medium. A range of spectroscopic techniques, including high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), and fluorescence spectroscopy (FL), have been employed to characterize the formation of micelles of AM@SDS. A remarkable increase in fluorescence intensity was observed upon interactions of AM with the microenvironment of SDS micelles. Conversely, the fluorescence intensity at 358 nm was significantly quenched in the presence of PA compared to other nitroaromatic compounds (NACs). The detection limit for PA was found to be 368 nM. Furthermore, the binary ensemble AM@SDS has demonstrated remarkable efficacy in detecting PA in real water samples from diverse sources such as lake, river, and tap water, achieving an exceptional recovery rate of up to 99.9 %.

Selective Detection of Picric Acid by Benzodiazepine Containing Enaminone Core as Receptor and Its Application to Real Water Sample Analysis.

Nitroaromatic compounds are highly explosive and illegitimate substances. Over a decade, chemists have been affianced in extensive research on the selective and sensitive detection of these nitroaromatic explosives for homeland security and environmental protection. The benzodiazepine-based enaminone (BDE) receptor has been synthesized by aqueous extract of onion catalyzed three-component reaction between o-phenylenediamine, dimedone with an aldehyde. The BDE probe is well analyzed and applied to a sensor that selectively detects picric acid (PA). UV-Vis and fluorescence spectroscopy were used to investigate the photophysical responses of the receptor (BDE). From the observed results BDE found turn-off fluorescence with the addition of picric acid and the lowest limit of detection and limit of quantification was achieved about 24.6 nM and 73.8 nM. The fluorescence quantum yield was attained about 0.28. The BDE-PA adduct formation was confirmed by 1H NMR titration analysis. The Job's plot analysis was performed through 1H NMR titrations and established the binding stoichiometry ratio of the BDE-PA adduct as 1:1 ratio. Further, DFT calculations supported the observed photophysical responses of BDE-PA adduct to confirm the molecular level interactions. The receptor was effectively applied to approximate level of picric acid in real water sample analysis.

Two-dimensional metal-organic framework nanoleaf embedded with nitrogen-doped carbon dots for monitoring of picric acid

A novel preparation of 2D metal–organic framework (Zn-MOF, ZIF-8) nanoleaf (ZIF-L) embedded with nitrogen-doped carbon dots (NCDs) was applied successfully. The NCDs are synthesized through hydrothermal treatment of citric acid and ethylenediamine exhibiting excitation wavelength independence (λex-independence) of 6 nm and higher quantum yield reaches 84 %. The ZIF-L embedded with NCDs generates a 2D continuous framework of NCDs@ ZIF-L nanocomposite. The nanocomposite was fully characterized by FTIR, XRD, TEM, and N2 adsorption-desorption mechanism. The XRD data reveals no significant change in the crystallinity of ZIF-L upon the encapsulation of NCDs, but it enhances the fluorescence emission. The synergetic cooperation between ZIF-L and NCDs might free active sites that lead to higher adsorption capacity and thus enhance their application in chemical sensing. The NCDs@ZIF-L nanocomposite synergistically combines active-rich-electron nanospaces with a high surface area, both of which are particularly beneficial for the selective detection of hazardous picric acid (PA) because of reinforced hydrogen bonding interactions with the hydroxyl groups of PA aromatic rings. The NCDs@ZIF-L framework is utilized to monitor PA as a nitro explosive compound in aqueous media exhibiting a high sensing activity and selectivity to detect PA in diluted solutions with a low detection limit (LOD) reaching 0.139 µM. The nanocomposite was also utilized in real water samples spiked with different concentrations of PA in tap water, with R % reaching 91.3–102 % and RSD % less than 5 %, showing their applicability to detect PA under circumstances.

The Preparation of Tetraarylethylene-Based Porous Polymer Nanoparticles for the Sensitive Detection of Picric Acid in Aqueous Media

The Preparation of Tetraarylethylene-Based Porous Polymer Nanoparticles for the Sensitive Detection of Picric Acid in Aqueous Media

Thermally versatile maleimide-based polymeric thin film for detection and separation of picric acid from polluted areas

2,4,6-Trinitrophenol, commonly known as picric acid, is a powerful explosive that has been used historically in military ammunition. Picric acid is extremely toxic and sensitive to friction and heat; thus, it is prone to accidental detonation at high temperatures. It is critical to detect and separate picric acid from the impacted areas. In the present study, we designed and developed a fluorescent copolymer (P1) for temperature-dependent picric acid detection. The solvatochromic and aggregation-induced emission (AIE) properties of P1 were utilized to detect picric acid at a high temperature of 40 °C (high alert level) by turn-off emission. Additionally, a polymeric thin film (F1) was fabricated by immobilizing P1 onto the surface of quartz slide. Notably, F1 retained its emissive properties across a range of temperatures (both relatively low and high alert levels), facilitated by its AIE characteristics. The portable film, F1, displayed a nanomolar sensitivity toward picric acid, making it suitable for on-site detection in aqueous media (neutral pH). Furthermore, F1 demonstrated efficient separation of picric acid from nitroaromatic explosive mixtures with a separation efficiency of 70 % over four cycles. Importantly, F1 exhibited practical utility in detecting and separating picric acid in real samples, highlighting its potential for environmental monitoring applications.

An investigation of the Excitation Wavelength-Dependent Dynamic Changes in the Mechanism of Detection of Picric Acid using Pyrene-Based Donor-Acceptor Systems.

Picric acid (PA) is an important industrial feedstock and hence the release of industrial effluents without proper remediation results in its buildup in soil and water bodies. The adverse effects of PA accumulation in living beings necessitate the development of efficient methods for its detection and quantification. Herein, we describe pyrene-based fluorescent sensors for PA, where pyrene is appended with electron-withdrawing groups, malononitrile, and 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene) malononitrile (DCDHF). These molecules displayed the typical emission of pyrene monomers, as well as a broad red-shifted emission resulting from an intramolecular charge transfer (ICT) in the excited state. Both the emissions displayed a turn-off response to PA with high selectivity and sensitivity and the lowest limit of detection was estimated as 27 nM. To prove the feasibility of on-site detection, test paper strips were prepared, which could detect PA up to 4.58 picograms. Using a combination of experimental and theoretical studies the mechanism of the detection was identified as primary/secondary inner filter effect, oxidative photoinduced electron transfer, or a combination of both depending on the excitation wavelength. Interestingly, the contribution of each of these mechanisms to the total quenching process varied with a change in the excitation wavelength.

Electrochemical sensing at the fingertips: Wearable glove-based sensors for detection of 4-nitrophenol, picric acid and diazepam

A wearable glove-based sensor is a portable and practical approach for onsite detection/monitoring of a variety of chemical threats. Herein, we report a flexible and sensitive wearable sensor fabricated on the nitrile glove fingertips by stencil-printing technique. The working electrodes were modified with multiwalled carbon nanotubes (MWCNTs)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) for sensitive and real-time analyses of hazardous or chemical treats, as picric acid (PA) explosive, diazepam (DZ) as drug-facilitated crimes and the emerging pollutant 4-nitrophenol (4-NP). The multi-sensing platform towards PA, 4-NP, and DZ offers the ability of in-situ qualitative and quantitative analyses of powder and liquid samples. A simple sampling by touching or swiping the fingertip sensor on the sample or surface under investigation using an ionic hydrogel combined with fast voltammetry measurement provides timely point-of-need analyses. The wearable glove-based sensor uses the square wave voltammetry (SWV) technique and exhibited excellent performance to detect PA, 4-NP, and DZ, resulting in limits of detection (LOD) of 0.24 μM, 0.35 μM, 0.06 μM, respectively, in a wide concentration range (from 0.5 μM to 100 μM). Also, we obtained excellent manufacturing reproducibility with relative standard deviations (RSD) in the range of 3.65%–4.61% using 7 different wearable devices (n = 7) and stability in the range of 4.86%–6.61% using different electrodes stored for 10 days at room temperature (n = 10), demonstrating the excellent sensor-to-sensor reproducibility and stability for reliable in-field measurements. The stretchable sensor presented great mechanical robustness, supporting up to 80 bending or stretching deformation cycles without significant voltammetric changes. Collectively, our wearable glove-based sensor may be employed for analyses of chemical contaminants of concern, such as explosives (PA), drugs (DZ), and emerging pollutants (4-NP), helping in environmental and public safety control.

Carbazolyl-Modified Neutral Ir(III) Complexes for Efficient Detection of Picric Acid in Aqueous Media.

Based on the electron-deficient property of picric acid (PA), two neutral Ir(III) complexes 1 and 2 modified with the electron-rich carbazolyl groups were synthesized and characterized. Both 1 and 2 exhibit aggregation-induced phosphorescence emission (AIPE) properties in THF/H2O. Among them, 2 is extremely sensitive for detecting PA with a limit of detection of 0.15 μM in THF/H2O. Furthermore, the selectivity for PA is significantly higher compared to other analytes, enabling the efficient detection of PA in four common water samples. The density functional theory calculations and the spectroscopic results confirm that the sensing mechanism is photo-induced electron transfer (PET).

A highly selective and sensitive quinoline-based fluorescent turn-off chemosensor for the detection of picric acid

A simple turn-off quinoline-based fluorescent chemosensor, 1-(6-amino-2-methyl-4-phenylquinolin-3-yl)ethan-1-one (QN) has been developed, synthesized, and characterized by various spectroscopic methods. This probe is selective for the sequential recognition of picric acid (PA), using a fluorescent turn-off method. QN exhibits a broad emission band at 504 nm, but fluorescence quenching occurs upon the addition of picric acid over other nitro compounds. The binding stoichiometric ratio between QN and picric acid was calculated to be 1:1 through Job's plot analysis, and the binding constant was determined. The limit of detection towards picric acid was found to be 9.33 µM. Further, the mechanistic approach for binding has been investigated by spectroscopic methods like 1H NMR titration, FT-IR studies, and density functional theory (DFT) studies.

Fluorescent Carbon Nitride Nanoparticles for Picric Acid Sensing.

Detection of nitroaromatic explosives is essential in the area of environmental safety. Fluorescent carbon nitride nanoparticles is a promising material for this purpose. Herein, we have prepared fluorescent carbon nitride nanoparticles (CNNPs) by one step thermal treatment of formamide. These fluorescent CNNPs is sensitive towards picric acid (PA) than other analytes both in aqueous medium and on test paper which is witnessed by fluorescence quenching based on inner filter effect (IFE). The PA detection with the fluorescent CNNPs is observed in the concentration ranges, 0 µM to 60 µM with linear range of 10 nM to 25 µM. The minimum detection limit in aqueous medium and solid phase are determined to be 26.20 nM and 10 µM respectively. Finally, the fluorescent CNNPs is applied for detection of PA in real water samples. The recoveries are in the ranges from 99.54 to 116.35% with relative standard deviation less than 3.85%. This proposed fluorescent method can act as suitable analytical technique to monitored PA concentration in water samples.

An Imidazole-Naphthalimide-Based pH-Sensitive Molecular Probe for Selective Detection of Picric Acid and Cell Imaging

An Imidazole-Naphthalimide-Based pH-Sensitive Molecular Probe for Selective Detection of Picric Acid and Cell Imaging

Pyrene based AIE-active probe for selective detection of picric acid through the inner filter effect channel in aqueous medium

The development of pyrene derivatives possessing the AIE feature have emerged as an intriguing area of research with potential applications in several domains. In the present study, we designed and developed an AIE active pyrene derivative for picric acid sensing in an aqueous medium. The design based on a single step condensation reaction and the product has been meticulously characterized by using NMR and Mass spectrometric techniques. In comparison to pristine pyrene, the synthesized pyrene derivative has a lower bandgap energy as a result of the intramolecular charge transfer between pyrene and 4-(methylthio)-2-oxo-2H-pyran-3-carbonitrile. The synthesized probe demonstrates a moderate level of fluorescence when dissolved in a solution, and it has exhibited a remarkable emission caused by aggregation at higher water percentages. The aggregates were meticulously characterized by DLS, SEM and TEM measurements. The spherically shaped aggregates have shown enhanced fluorescence quantum yield and lifetime, rendering them a more suitable option for sensor applications. The aggregates were effectively employed as a fluorescent probe for the detection of picric acid in an aqueous medium. The probe exhibited a notable level of selectivity and sensitivity towards picric acid, as evidenced by its low detection limit of 4.47 nM. Moreover, the quenching mechanism was ascribed to the inner filter effect, providing supporting evidence from both experimental and mathematical calculations. The findings indicate that the probe has potential as a feasible choice for a picric acid sensor.

Intermolecular π-π interactions-induced aggregation based on bispyrene for ultrasensitive detection of picric acid (PA) and 2,4-dinitrophenol (DNP)

It was still important to explore excimer emission-based fluorescence probes for nitroaromatics detection by formation or destruction of pyrene excimer with strong emission change. In this work, we have synthesized a simple bis(pyrene) derivative (BisPyH) and studied its optical behavior by using UV–vis and fluorescent spectroscopy. In pure DMSO solution, it emitted a weak blue fluorescence due to the formation of excimer states, on the contrary, the BisPyH in the DMSO/H2O (v/v, 1:1) mixture solution was self-assembled to form aggregates via intermolecular π-π interactions among pyrene units, giving almost 10-fold fluorescence enhancement compared to that in pure DMSO solution. The formed aggregates just offered a perfect platform for the selective detection PA and DNP explosives by quenching the bright green intermolecular-excimer emission in competitive environment. BisPyH exhibited a limit of detection (LOD) towards PA, and DNP as low as 7.32 × 10−8, and 8.11 × 10−8 M, respectively. Subsequently, the fluorescence quenching mechanism was demonstrated by the density functional theory (DFT), UV–vis and fluorescence spectra, SEM, and the quenching constants. Furthermore, filter paper strips and thin-layer chromatography (TLC) plates coated with BisPyH were able to detect PA and DNP in the practical application.

Design, synthesis, and spectrofluorimetric analysis of a novel fluorene-based chemosensor for the selective detection of picric acid

Fluorene-based probes are efficient candidates for sensing nitroaromatics and toxins. A novel fluorophore based on fluorene and terephthalaldehyde 1,4-YBF (1,4-ylidene-bis-fluorene) has been designed and synthesized for the efficient sensing of 2,4,6-trinitrophenol (picric acid) in solution. X-ray crystallographic studies, NMR, and mass analyses revealed the molecular stacking and exact structure of 1,4-YBF, which was further structurally optimised using the DFT technique. The optical properties of the newly synthesized compound were studied using UV–Vis and spectrofluorimetric analyses. The fluorophore was subjected to detailed sensing studies of various nitroaromatics, among which it was identified that picric acid (PA) exhibited the maximum quenching efficiency. The excellent sensing ability of the fluorophore was probably attributed to the photoinduced electron transfer (PET) mechanism. Further, pH studies and interference studies, along with its high selectivity towards PA and an LOD of 0.314 µM, revealed 1,4-YBF to be efficient in the detection of picric acid at a micromolar level.

Metal-organic frame material encapsulated Rhodamine 6G: A highly sensitive fluorescence sensing platform for the detection of picric acid contaminants in water

As a water pollutant with excellent solubility, 2,4,6-trinitrophenol (also known as picric acid, PA) poses a potential threat to the natural environment and human health, so it is crucial important to detect PA in water. In this study, a novel composite material (MIL-53(Al)@R6G) was successfully synthesized by encapsulating Rhodamine 6G into a metal-organic frame material, which was used for fluorescence detection of picric acid (PA) in water. The composite exhibits bright yellow fluorescence emission with a fluorescence quantum yield of 58.23 %. In the process of PA detection, the composite has excellent selectivity and anti-interference performance, and PA can significantly quench the fluorescence intensity of MIL-53(Al)@R6G. MIL-53(Al)@R6G has the advantages of fast detection time (20 s), wide linear range (1–100 µM) and low detection limit (4.8 nM). In addition, MIL-53(Al)@R6G has demonstrated its potential for the detection of PA in environmental water samples with satisfactory results.

Tellurium Containing Long Lived Emissive Fluorophore for Selective and Visual Detection of Picric Acid through Photo-Induced Electron Transfer.

A novel tellurium (Te) containing fluorophore, 1 and its nickel (2) and copper (3) containing metal organic complex (MOC) have been synthesized to exploit their structural and optical properties and to deploy these molecules as fluorescent probes for the selective and sensitive detection of picric acid (PA) over other commonly available nitro-explosives. Furthermore, density functional theory (DFT) and single crystal X-ray diffraction (SCXRD) techniques revealed the inclusion of "soft" Tellurium (Te) and "hard" Nitrogen (N), Oxygen (O) atoms in the molecular frameworks. Owing to the presence of electron rich "N" and "O" atoms along with "Te" in the molecular framework, 1 could efficiently and selectively sense PA with more than 80 % fluorescence quenching efficiency in organic medium and having detection limit of 4.60 μM. The selective detection of PA compared to other nitro-explosives follows a multi-mechanism based "turn-off" sensing which includes photo-induced electron transfer (PET), electrostatic (π-π stacking and π-anion/cation) interaction, intermolecular hydrogen bonding and inner filter effect (IFE). The test strip study also establishes the sensitivity of 1 for detection of PA.

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.

Triazole-Bridged Anthracene-Sugar Derivative for the Detection of Picric Acid and Au(III) Ions in Water Medium and Real Applications

Triazole-Bridged Anthracene-Sugar Derivative for the Detection of Picric Acid and Au(III) Ions in Water Medium and Real Applications

Donor-acceptor covalent organic polymers as real-time luminescent sensors for detection and removal of nitro-aromatics from an aqueous solution

Creating suitable monitoring probes that exhibit strong fluorescence properties for sensitive detection and effective removal of nitro-aromatics remains a challenge. Herein, triazine-based N-rich donor–acceptor covalent organic polymers (TBN-COPs) with unique electron-rich channels, tunable pore size distribution, and outstanding specific surface areas were rational designed and synthesized for the highly selective detection and effective removal of nitro-aromatics. The sensing properties for electron-deficient benzene derivatives were explored. Compared with other types of TBN-COP candidates, TBN-1 showed a better luminescence response to nitro-aromatics, especially for picric acid (PA). The 0.15 ppm detection limits and 2.89*105 as Ksv could be realized for PA detection by TBN-1. Besides, there were no additional fluorescence responses to the electron rich benzene derivatives, demonstrating the specific selectivity of nitro-aromatics by TBN-1. The energy and charge transfer mechanisms for the hyper nitro-aromatics sensing properties of TBN-1 were further elucidated according to the energy level simulation, and to both the spectroscopic and electrochemical analysis. The merits of TBN-1 are unreservedly manifested when further testing the adsorption performance of TBN-1 for nitro-aromatics removal. The mechanism for the excellent nitro-aromatics adsorption performance of TBN-1 is revealed by coupling model fitting and chemical computation, which indicates the π-π stacking interaction and high electron density of the material to facilitate its combination with nitro-aromatics. Therefore, TBN-1 is a promising candidate to selectively detect and effectively remove nitro-aromatics, and can hence be applied in security checking and environmental conservation.

Solvothermal self-assembly of seven lanthanide(III) coordination polymers using diphenic acid and 1,10-phenanthroline as co-ligands: Efficient detection of picric acid and Cu2+ ions in aqueous medium by europium based coordination polymer

Lanthanide based coordination polymers (Ln-CPs) act as efficient chemo-sensors on interaction with the target analyte and show a detectable variation in their optical properties. This work demonstrates interaction of metal ions and nitroaromatic compounds with Eu based CP resulting in quenching of luminescence emission intensity. Approaching towards this aim, seven iso-structural lanthanide coordination polymers having the formulae, [Ln(diphen)1.5(1,10-phen)(H2O)] where Ln = Sm (1), Gd (3), Dy (5), {[Ln(diphen)1.5(1,10-phen)(H2O)]·OH} Ln = Eu (2), Er (7) and {[Ln(diphen)1.5(1,10-phen)(H2O)]·CH3CN·H2O} Ln = Gd (4), Ho (6) (diphen = diphenic acid, 1,10-phen = 1,10 Phenanthroline), were assembled solvothermally by using diphenic acid and 1,10-Phenanthroline as ligands. These lanthanide coordination polymers were characterized by Single-crystal X-ray diffraction, FTIR, Powder X-ray diffraction, Thermogravimetric analysis, UV–visible spectroscopy and Photoluminescence. The CPs 1–7 possess one-dimensional (1D) infinite chain-like structures which crystallize in the monoclinic C2/c space group. The photoluminescence properties of CP 2 exhibit its sensing ability to detect some toxic nitroaromatic compounds and d-block metal ions. However, CP 2 shows highly sensitive behavior for the recognition of Cu2+ and picric acid as indicated by efficient luminescence quenching with the low limit of detection. Other metal ions (viz., Cr3+, Cu2+, Co2+, Zn2+, Mn2+, Ni2+, Cd2+, and Hg2+), and nitro compounds (viz., PA, m-DNB, p-NP, p-NA and NB) were also screened for sensing potential of CP 2.