Picric Acid In Water Samples Research Articles

Electrospun nanofiber sheets mixed with a novel triphenylamine-pyrenyl salicylic acid fluorophore for the selective detection of picric acid

A novel tripod-shaped compound 2 was synthesized through the Sonograsira and the Suzuki cross-coupling reaction in 2 steps. Thus, cellulose acetate electrospun nanofiber sheets mixed with compound 2 were used for the detection of picric acid (PA). Compound 2 displayed the most sensitive fluorescence quenching reaction to picric acid (PA) among nitroaromatic compounds with a linear concentration range of 2.0–50 µM and a limit of detection (LOD) of 0.57 µM. In addition, the electrosphun nanofiber combined with compound 2 may be employed as a sensor to detect PA in the environment via an efficient fluorescence quenching resulting from the photoinduced electron transfer (PET) process. Fluorescence mode and density functional theory (DFT) calculations were used to examine the selective interaction of sensors with PA. This compound 2 was successfully employed for selective detection of PA in water samples. Interestingly, compound 2 was designed for rapid naked-eye detection of PA under black light, high sensitivity, high selectivity, and convenience for on-site PA detection. Compound 2 demonstrated that these sensors might be used to construct novel detection devices for PA analysis in real samples.

A novel amino functionalized three-dimensional fluorescent Zn-MOF: The synthesis, structure and applications in the fluorescent sensing of organic water pollutants

An amino functionalized three-dimensional (3D) Zn-MOF with molecular formula Zn(NH2bdc)(mbib) (complex 1) has been synthesized by using solvothermal method. The structure, purity, stability and morphology of complex 1 was fully characterized with single-crystal X-ray diffraction, PXRD, FT-IR, TGA, TEM, et al. The characterization results revealed that complex 1 crystallizes in the orthorhombic space group Pna21. In the structure of complex 1, each NH2bdc2− ligand connected to two Zn(II) to form a 1D zigzag chain which was further connected by the mbib ligands to give a fourfold interpenetration 3D framework. The single-crystal X-ray diffraction analysis indicated that the 3D framework of complex 1 was functionalized with free amino groups both on the surface and in the channels. Characteristic fluorescent emission centered at 430 nm which could be remarkably enhanced in water was observed, indicating complex 1 might be a promising candidate for the fluorescent sensing of water pollutants. The functionalized amino groups remarkably enhanced the selectivity and sensitivity of complex 1. Gradually fluorescence quenching of complex 1 was recorded in the fluorescent titration experiments with good quantitative relation after addition of acetone or picric acid in water samples. The experimental detection limits for acetone and picric acid were 0.03% (%V) and 340 nM, respectively. Plausible mechanisms for the fluorescent quenching sensing of acetone and picric acid were proposed.

A recyclable fluorescent probe for picric acid detection in water samples based on inner filter effect

1-Aminopyrene@ZIF-8 composite was synthesized as the fluorescent probe for picric acid (PA) based on inner filter effect. The probe displayed selective response toward PA within 10s, and a linear range was obtained from 1 to 150μM with detection limit of 0.3μM, which is much lower than the permissible level of PA in drinking water reservoir (0.5mgL-1/2.2μM) set by China's State Environmental Protection Administration (GB3838-2002). Most importantly, the probe possessed excellent recyclability and could be recycled for at least six times. It was further applied to the detection of PA in water samples, and satisfactory recoveries were obtained in the range of 96.0-104.0%.

Synthesis of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Selective Detection of Picric Acid in Water Samples.

In this work, fluorescent nitrogen-doped carbon dots (N-CDs) were pyrolysis synthesized using edetic acid and acrylamide as precursors without further surface modication. The as-prepared N-CDs were mono-dispersed spherical nanoparticles with an average diameter of 3.25 nm. The blue fluorescence emission was dependent of the excitation wavelengths, releasing stable and strong blue fluorescence under the maximum excitation wavelength. More strikingly, after adding picric acid (PA), the fluorescence of N-CDs aqueous solution gave rise to the obviously fluorescence quenching due to the inner filter effect. Under the optimum conditions, the fluorescence probe can be used for the selective detection of PA with a wide linear relationship in the range of 0.01-32 μM and the detection as low as 0.046 μM. Depending on the fluorescence quenching phenomenon, the resultant fluorescent probe for accurate and selective monitor of PA in Fenhe river samples was explored. The recoveries fell in the range of 97.13%-106.21% and the relative standard deviation was below 3% with satisfactory results.

AIE-active luminogen for highly sensitive and selective detection of picric acid in water samples: Pyridyl as an effective recognition group

Detection of nitroaromatic explosives especially picric acid (PA) is considerably worth concern on human safety and homeland security. Herein, we developed an effective probe (APPTPEP) for PA detection in aqueous medium by combination of 1,4-dihydropyrrolo[3,2-b]pyrrole with tetraphenylethylene and pyridine units. The incorporation of tetraphenylethylene unit in the backbone endows the APPTPEP a significant aggregation induced emission (AIE) behavior. Pyridyl group was proved as recognition site for PA and their strong interaction was confirmed by 1H NMR titration and supported by theoretical calculation. Owing to this strong affinity, APPTPEP exhibited high selectivity and sensitivity (limit of detection 31.5 nM) to PA over other nitroaromatic compounds. This research provides new insights into the rational design of AIE-active materials for effective sensing application.

A fluorescent chemosensor based on nonplanar donor-acceptor structure for highly sensitive and selective detection of picric acid in water

Direct detection of picric acid in water samples is very important for social security and environmental protection. Herein, a novel donor-acceptor type fluorophore 3-(benzyloxy)-2-(4-(di-p-tolylamino)phenyl)-4H-chromen-4-one has been designed, and synthesized. Due to its aggregation-induced emission enhancement characteristic, this fluorophore showed a very strong fluorescence in water. This fluorophore was then employed as highly sensitive chemosensor for picric acid, with a limit of detection of 370 nM in water. Moreover, this sensor showed very high selectivity towards picric acid among interfering nitroaromatics. At last, the sensing mechanism was carefully studied by using DFT computation and NMR spectra. This work provided a practical and reliable detection method for picric acid in water samples.

Hydrothermal synthesis of fluorescent nitrogen-doped carbon quantum dots from ascorbic acid and valine for selective determination of picric acid in water samples

ABSTRACTNitrogen doped carbon quantum dots (N-CQDs) were synthesised by a hydrothermal method using ascorbic acid and valine as precursors. The as-synthesised N-CQDs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV−vis absorption spectra, as well as fluorescence spectrophotometer. The results revealed that the as-prepared N-CQDs were spherical shaped with an average diameter of 4 nm and emitted bright blue photoluminescence with a quantum yield of approximately 4.8 %. Additionally, we found that the fluorescence of the N-CQDs was intensively quenched by the addition of picric acid (PA). The decrease of the fluorescence intensity made it possible to determine PA in the linear range of 0.06–7.81 µg ml–1 based on the fluorescence resonance energy transfer between PA and N-CQDs. The detection limit was as low as 11.46 ng ml–1. The proposed approach was further successfully applied for the determination of PA in water sample collected from Fenhe river for public safety and security, suggesting its great potential towards water routine analysis.

Removal, preconcentration and spectrophotometric determination of picric acid in water samples using modified magnetic iron oxide nanoparticles as an efficient adsorbent

A simple, fast and sensitive spectrophotometric method is developed for removal, preconcentration and determination of trace amounts of picric acid in water samples. Magnetic iron oxide nanoparticles (MIONPs) were synthesized and characterized by transmission electron microscopy (TEM). The magnetic nanoparticles were coated with cetyltrimethylammonium bromide (CTAB) and were applied for fast separation, preconcentration and spectrophotometric determination of picrate anion (the ion of picric acid) in an aqueous solution. The separation, preconcentration procedure is fast and will be completed in 2min. Methanol is used for desorption of adsorbed picrate anion. The effects of important parameters such as pH of aqueous medium, CTAB dosage, adsorbent amount, temperature, electrolyte concentration, desorbing solvent and interfering ions on the adsorption of picrate anion were investigated. The method showed good linearity for the determination of picric acid in the concentration range of 0.02–1.00μgmL−1 with a regression coefficient of 0.999. The limit of detection (LOD) is obtained to be 0.007μgmL−1. The relative standard deviation (RSD) for 0.03μgmL−1 and 0.8μgmL−1 of picric acid were 3.98% and 1.97% respectively. Picric acid was separated, preconcentrated and determined successfully in spiked samples of Karoon River water.

A reusable optical sensing layer for picric acid based on the luminescence quenching of the Eu—thenoyltrifluoroacetone complex

A new luminescene sensing layer for the determination of picric acid based on reversible luminescence quenching of the Eu-thenoyltrifluoroacetone (TTA) complex was proposed. The optosensor was based on the electrostatic immobilization of the Eu—TTA complex on the chelating resin of Chelex 100 packed in the flow cell, which can induce a room temperature luminescence behaviour in an aqueous phase. The quenching mechanism was also studied. The detection limit was 2 × 10 −6 M by using a response time of 1 min. The optosensor was easy to prepare and the lifetime of the optosensor was at least 1 month. The optosensor has been used for the direct determination of picric acid in water samples and the indirect measurement of some drugs such as quinine.