Determination Of Diphenylamine Research Articles

La-doped NiWO4 coupled with reduced graphene oxide for effective electrochemical determination of diphenylamine.

Diphenylamine (DPA) is a harmful pesticide widely used to control post-harvest scald of fruits. In this study, rapid and sensitive determination of DPA was realized by the development of an effective electrochemical sensor, which was fabricated by coupling La-doped NiWO4 nanoparticles (La/NiWO4) with reduced graphene oxide (rGO), and the obtained rGO/La/NiWO4 nanocomposite was modified on glassy carbon electrodes (GCEs). The morphologies, structures and compositions were well characterized, and the effects of La doping and the introduction of rGO on the crystal structure and electrochemical performance were discussed. The incorporation of both La and rGO was found to enhance the active surface area and improve conductivity, resulting in the enhanced electrocatalytic performance of rGO/La/NiWO4/GCE, including a wide linear range (0.01-500 μM), a low detection limit (0.0058 μM) and high sensitivity (1.778 μA μM-1 cm-2). The fabricated sensor was further used for DPA detection in fresh apple extract to evaluate its practicality and demonstrated excellent recoveries ranging from 99.52 to 104.70%.

Determination of Diphenyl Amine (DPA) Stabilizer in Propellants – A Minireview

AbstractThere is concern about the aged propellants as the proportion of stabilizer, diphenyl amine (DPA), keeps on reducing while maintaining the propellant formulation safe. This is a very important issue as it keeps the propellant as well as the surrounding safe from any possible mishap. Therefore, the determination of residual DPA/DPA derivatives in the propellant is of utmost importance. Various attempts have been made to determine residual DPA/derivatives content in the propellant. In this review the detection methods have been compiled and analysed for their implications, detection limit and standard deviation. The methods attempted for detection comprise volumetric, chromatographic, electroanalytical, spectroscopic and thermoanalytical techniques. The volumetric method was tried in the initial attempts by adopting chemical reactions. Chromatographic methods were reported by adopting different procedures and variations. These have been discussed in details. Electroanalytical methods have become one of the important techniques to determine the residual DPA that has been discussed in detail with incorporation of various modifications. Spectroscopic methods were also deployed to determine the DPA content in the propellant. The methods, being very straight forward and clean, have been considered effective in determination. Differential scanning calorimetry has also been tried for finding the DPA content in the propellant sample by adopting different combinations, which is also incorporated for discussion in this paper.

Efficient and green synthesis of silver nanocomposite using guar gum for voltammetric determination of diphenylamine

In this study, silver nanoparticle embedded on guar gum (AgNP/GG) nanocomposite was synthesized thoroughly in greenway via a simple in situ method by silver salt reduction using the guar gum (GG) polymer matrix. The highly water-soluble polysaccharide material (GG) was served as both stabilizing and reducing agent. Its structure and morphology were characterized by XRD, FT-IR, TEM, and UV−Vis spectroscopy. EIS, CV, and DPV methods have also been employed to investigate the electrochemical performance of the AgNP/GG nanocomposite. Analytical parameters such as loading amount of catalyst, scan rate, pH value, cyclic stability, repeatability, and reproducibility were optimized. The AgNP/GG/SPCE shows a distinct electrocatalytic oxidation of diphenylamine (DPA) in a wide linear range (WLR) of 0.01−9.09 µM, a higher sensitivity of 6.879 µM cm−2, and a limit of detection (LoD) of 5.4 nM (S/N = 3). The fabricated electrode exhibits an outstanding electrocatalytic performance in terms of good reproducibility, high stability, and acceptable anti-interference ability. In addition, this work advances the feasibility to determine DPA in apple juice sample with satisfactory recovery results.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted liquid-liquid micro-extraction combined with HPLC-FLD for diphenylamine determination in fruit

ABSTRACT In this paper, novel high extraction efficiency hydrophobic eutectic solvents (DESs), n-octanoic acid as a hydrogen bond donor (HBD) and menthol as a hydrogen bond acceptor (HBA), were selected from five hydrophobic DESs to extract trace diphenylamine (DPA) in fruits apple, pear and orange under ultrasonic-assisted liquid-liquid micro-extraction (UA-LLME) technology before high-performance liquid chromatography (HPLC) analysis. Working parameters such as the DESs type, molar ratio, extractant volume, and ultrasonic time of the LLME hydrophobic DESs technology were optimised. Average recoveries between 96% and 108% were obtained on actual samples. This method gave lower detection limit (LOD) than other existing methods due to combining the high-efficiency extraction of hydrophobic DES and high sensitivity of fluorescence detector. This method was sensitive and eco-friendly, and can be used for the determination of trace components in fruits.

Spherical phosphomolybdic acid immobilized on graphene oxide nanosheets as an efficient electrochemical sensor for detection of diphenylamine

Herein, a phosphomolybdic acid (PMo12) and graphene oxide (GO) based new electrochemical sensor (PMo12/GO/GCE) was developed for determination of diphenylamine (DPA). Spherical PMo12 was uniformly anchored on GO matrix by cost-efficient and facile electrodeposition approach. Cyclic voltammetry and differential pulse voltammetry were utilized to investigate electrochemical behavior of DPA on PMo12/GO/GCE. As expected, the sensor showed remarkable electrocatalytic activity toward DPA. The linear amperometric response of DPA at 0.55 V (vs. SCE) was obtained in a wide concentration range of 0.05 ~ 400 µM with a detection limit of 6.0 nM (S/N = 3). In addition, PMo12/GO/GCE displayed favorable reproducibility, selectivity and durable stability. The feasibility of constructed sensor was verified by detecting DPA in real apple juice samples with a satisfactory test results, showing its application prospects in detecting DPA in fruit samples.

A simple GC–MS method for the determination of diphenylamine, tolylfluanid propargite and phosalone in liver fractions

In this study, an accurate and robust gas chromatography/mass spectrometry method was developed for quantitative analysis of diphenylamine, tolylfluanid, propargite and phosalone in liver fractions. Different injector parameters were optimized by an experimental design technique (central composite design). An optimal combination of injector temperature (°C), splitless time (min) and overpressure (kPa) values enabled to maximize the chromatographic responses. Sample preparation was based on protein precipitation using trichloroacetic acid followed by liquid-liquid extraction (LLE) of the pesticides with hexane. All compounds and endrin as internal standard were quantified without interference in selected ion monitoring mode. The calibration curves for diphenylamine, tolylfluanid, propargite and phosalone compounds were linear over the concentration range of 0.1 to 25 μM with determination coefficients (R2) higher than 0.999. A lower limit of quantification of 0.1 μM was obtained for all analytes, i.e. 422.5, 868.0, 876.2 and 919.5 μg/kg of liver fraction (hepatocytes) for diphenylamine, tolylfluanid, propargite and phosalone, respectively. All compounds showed extraction recoveries higher than 93%, with a maximum RSD of 3.4%. Intra- and inter-day accuracies varied from 88.4 to 102.9% and, imprecision varied from 1.1 to 6.7%. Stability tests demonstrated that all pesticides were stable in liver extracts during instrumental analysis (20 °C in the autosampler tray for 72 h) following three successive freeze-thaw cycles and, at −20 °C for up to 12 months. This simple and efficient analytical procedure is thus suitable for metabolism studies or for assessing mammals liver contamination.

Comments on “Novel molecularly imprinted polymer based on β-cyclodextrin@graphene oxide: Synthesis and application for selective diphenylamine determination”

This comment mainly deals with a mistake of applying pseudo-first-order kinetic model for testing the kinetic behaviors of adsorption.

Detecting the concentrations of diphenylamine in air of workplace with HPLC

Objective: To establish the method of detecting the concentrations of diphenylamine in air of workplace with high performance liquid chromatographic (HPLC) . Methods: According to standards of methods for determining the chemical substances in workplace air, diphenylamine in the air was collected by glass fiber filter treated with sulfuric acid, then dissolved by methanol and determined by high performance liquid chromatography with UV-detector. Results: There was a linear relationship within the range of 0-30.0 μg/ml, and regression equation was y=8425.6x-150.7, correlation coefficient was 0.999 9, the detection limit was 0.045 μg/ml. The lowest detected concentration was 0.030 mg/m(3) (sampling volume 15 L) . The within-run precision was 2.41 ℅-3.02%, the between-run precision was 3.11%-4.45%. The desorption efficiencies was 97.8℅ and the sampling efficiencies were 100%. The samples in glass fiber filter could be stored for 7 d at room temperature. Conclusion: The present method could meet with the requirements of Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace and be feasible for determination of diphenylamine in workplace air.

Least Absolute Shrinkage and Selection Operator as a Multivariate Calibration Tool for Simultaneous Determination of Diphenylamine and its Nitro Derivatives in Propellants

AbstractDetermination of diphenylamine (DPA) and its nitro derivatives received great attention for storing, deposition and on‐time usage of propellants. Herein, we present a novel and simple method for simultaneous determination of DPA and its nitro derivatives in solid propellants using UV‐Vis spectroscopy and chemometrics techniques. The UV‐Vis spectra of the analytes revealed strong overlap and it was difficult to determine them individually in their mixture without any separation and purification. To tackle the overlapping problem in collected spectra, analysis of first‐order UV‐Vis data was performed using multivariate calibration techniques. In this way, principle component regression (PCR), different modes of partial least square (PLS) and least absolute shrinkage and selection operator (LASSO) have been used for correlating the collected spectra to the concentration of DPAs in synthetic and real samples. The important variables were selected by confining the L1‐norm of the regression coefficients in multivariate model via the shrinkage and selection operator in LASSO approach. The results obtained by LASSO regression technique in this work were superior to those obtained by different modes of PLS algorithm. Moreover, it is shown that LASSO can be used as a reliable variable selection and modeling technique in multivariate calibration studies. Generally, the proposed strategy in this work is simple, non‐destructive, low‐cost and rapid and can be effectively applied for simultaneous determination of DPA and its nitro derivatives in solid propellants.

Assessment of divergent functional properties of seed-like strontium molybdate for the photocatalysis and electrocatalysis of the postharvest scald inhibitor diphenylamine

The bifunctional activity of strontium molybdate (SrMoO4) in the photodegradation and electrocatalytic determination of diphenylamine (DPAH) was identified and demonstrated. The photocatalytic and electrocatalytic activity of SrMoO4 were influenced by its structural properties. Those structural properties are scrutinized by various physical spectroscopic and microscopic tools. In this work, we mainly concentrated on two phenomena of SrMoO4, the photon absorption and electrochemical behavior. UV–visible spectroscopy was used to assess the photon absorption characteristics of SrMoO4, which mostly generates OH radicals for the degradation of DPAH. The rate of photodegradation was demonstrated in terms of irradiation time, pH, catalyst loading, and initial concentration. On the other hand, voltammetry was used to evaluate the electrochemical behavior of SrMoO4. The overall reaction pathways of DPAH showed that the major contribution of the reaction is generation of radical cations (DPAH+). Therefore, we can determine the concentration of DPAH by measuring DPAH+. Differential pulse voltammetry is a suitable analytical tool to measure DPAH+, which determined the DPAH in the linear range 0.1–35µM and with a lowest detection limit of 30nM. One of the greatest challenges of this determination is the selectivity, because DPAH+ is highly reactive toward similar functionalities such as anions and cations. Therefore, we carefully investigated and discussed the selectivity in the presence of interfering compounds.

Novel molecularly imprinted polymer based on β-cyclodextrin@graphene oxide: Synthesis and application for selective diphenylamine determination

A sensitive and selective molecularly imprinted polymer (MIP) for the determination of diphenylamine (DPA) was developed based on host-guest interactions of a cyclodextrin-based polymer which possesses an inherent affinity for the target. The proposed GO@MIP has been prepared using the graphene oxide (GO) sheets as surface of polymerization, DPA as target molecule, β-cyclodextrin (β-CD) and acrylamide (AM) as functional monomers, azobisisobutyronitrile (AIBN) as initiator and N, N methylene bisacrylamide (MBAm) as crosslinker which denoted as GO@MIP nanocomposite. The MIP sites were formed by the inclusion complex through interaction of DPA and β-CD, followed by extraction of target. The resulting GO@MIP nanocomposite possess a fast adsorption kinetics, highly improved imprinting effect, high adsorption capacity, and it can be applied to fast extraction of DPA. The resultant GO@MIP nanocomposite was characterized using the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) analysis. On the other hand, the non-imprinted polymer (GO@NIP nanocomposite) has been synthesized and was used in the adsorption experiments. The MIP exhibited good affinity with a maximum adsorption capacity of 95.98mgg−1 and excellent selectivity toward DPA than other structural analogues such as 2-amino benzophenone and dithizone.

An Efficient Method for Determination of the Diphenylamine (Stabilizer) in Propellants by Molecularly Imprinted Polymer based Carbon Paste Electrochemical Sensor

AbstractIn this work we report efficient molecularly imprinted polymer (MIP) based carbon paste electrode sensor for the determination of diphenylamine in aged propellant. Initially, diphenylamine (DPA)‐MIP was synthesized by using methacrylic acid (monomer) and ethylene glycol dimethyacrylate (cross‐linker). Developed DPA‐MIP was analyzed by Fourier transform infrared spectroscopy and Field‐emission scanning electron microscopy. The sensor was incorporated as electrode in cyclic voltammetry. The sensor response was linear in the range of 0.5–3 mM DPA concentration. The lower detection limit obtained for sensor was 0.1 mM. The developed sensor was used for the determination of DPA in propellant systems. Same electrode was used for three repeated analysis without significant decrease in efficiency.

Voltammetric Determination of Dinonyl Diphenylamine and Butylated Hydroxytoluene in Mineral and Synthetic Oil

ABSTRACTA method is reported for the determination of diphenylamine and butylated hydroxytoluene in mineral and synthetic oil. The procedure used differential pulse voltammetry with a glassy carbon electrode. This method was then used for determining these antioxidants in supporting electrolyte consisting of dilute sulfuric acid and sodium dodecyl sulfonate in ethanol. Anodic peaks were obtained for both analytes. Oxidation peaks at 250 mV were observed from a mixture of butylated hydroxytoluene and dinonyl diphenylamine, allowing their simultaneous determination. This approach was successfully used for the determination of dinonyl diphenylamine and butylated hydroxytoluene in fortified mineral and synthetic oils with good accuracy and precision.

Determination of Diphenylamine in Gunshot Residue by HPLC-MS/MS

A high performance liquid chromatography tandem mass spectrometry/mass spectrometry (HPLC-MS/MS) protocol was developed for the determination of diphenylamine (DPA). Four productions of DPA were selected for qualitative assay and the peak area of the main product ion for quantitation. By means of separation using an Agilent Extend-C18 column (CA, USA) (150 mm × 4.6 mm, 5 μm) with methanol-water (90:10) as the mobile phase, DPA was detected by electrospray ionization (ESI) tandem mass spectrometry in positive mode. The linearity of the peak area versus concentration ranged 5-500 ng/mL, r 2 = 0.9978. The limit of detection (S/N =3) of this method was 0.3 ng/mL. This method is applicable for the determination of DPA in gunshot residue.

Determination of Diphenylamine in Agricultural Products by HPLC-FL.

A method for the determination of diphenylamine in agricultural products was developed. Diphenylamine was extracted with acetonitrile from a sample under an acidic condition, passed through a C18 cartridge column, re-extracted with n-hexane, cleaned up on a PSA cartridge column, determined by HPLC with fluorescence detector and confirmed by liquid chromatography with tandem mass spectrometry. Average recoveries (n=5) from brown rice, corn, soybeans, potato, cabbage, eggplant, spinach, orange, apple and green tea were in the range from 76.7 to 94.9%, and the relative standard deviations were from 0.6 to 5.8% at concentrations equal to the maximum residue limits (MRLs). The quantification limits were 0.01 mg/kg, which is the uniform limit in the positive list system for agricultural chemical residues in food in Japan.

A Double Extraction Method for Determination of Diphenylamine in Fruits by GC/MS

A double extraction method comprising ultrasound assisted QuEChERS treatment combined with hollow-fiber liquid phase micro extraction was developed for the determination of diphenylamine in various fruit samples using gas chromatography coupled to a single-quadrupole mass spectrometer. Briefly, a known portion of fruit sample underwent an ultrasound assisted QuEChERS treatment. The organic phase resulting from QuEChERS treatment of a fruit sample was diluted 5-fold with pure water followed by a hollow fiber liquid-phase micro extraction procedure for further cleaning and preconcentration. In the late procedure, the analyte was extracted from the diluted sample into a thin layer of (dodecane+10% tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. The analyte was back extracted into acetonitrile located inside the lumen of the hollow fiber. Selected ion monitoring mass spectrometry was used for quantitative determination. The calibration curve was linear over the concentration range of 20-200 µg kg-1. The relative recovery was in the range of 76-108% while, precision varied between 6.4-13.7%. Finally, the applicability of the joint method was tested through analysis of diphenylamine in various fruit samples.

Determination of diphenylamine residue in fruit samples by supercritical fluid extraction followed by vesicular based-supramolecular solvent microextraction

The combination of supercritical fluid extraction (SFE) with supramolecular solvents-based microextraction (SSME) has been developed for extraction and determination of diphenylamine (DPA) in the peel of fruit samples. High performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection was applied for determination of the DPA. The supramolecular solvent was produced from coacervation of decanoic acid aqueous vesicles in the presence of tetrabutylammonium (Bu4N+). In SFE–SSME procedure, the dehydrated samples were loaded into SFE extraction vessel and extraction was performed in a prescribed time. The extracted analyte was collected in 5mL aqueous solution (pH=3) and introduced to SSME. The effective parameters on the SSME efficiency were studied and optimized. The Taguchi orthogonal array (OAD) experimental design with an OA16 (45) matrix was employed to optimize the SFE conditions. The calibration plot was linear in the range of 0.5–7.0mgkg−1 and the limit of detection (LOD), based on S/N of 3 was 0.3mgkg−1. Interday RSDs% lower than 10.3%, and intraday RSDs% lower than 7.1% were obtained. Analysis of DPA in different fruit peel showed that the improved technique has great potential for extraction and determination of DPA in fruit samples.

Application of a nanostructured supramolecular solvent for the microextraction of diphenylamine and its mono-nitrated derivatives from unburned single-base propellants.

A supramolecular solvent made up of nano-sized inverted hexagonal aggregates of 1-octanol is proposed for the microextraction of diphenylamine and its mono-nitrated derivatives in unburned single-base propellants. The procedure included the extraction of sub-gram quantities (30 mg) of homogenized propellant with 1.5 mL of the supramolecular solvent. Several conditions affecting extraction efficiency, for example the concentrations of the major components of the supramolecular solvent (tetrahydrofuran and alkanol), alkanol type, solvent pH, and extraction time, were investigated and optimized. The main forces for the microextraction of analytes in the nanostructured supramolecular solvent include both dispersion and hydrogen bond interactions. This mixed-mode mechanism resulted in high extraction efficiencies reaching low method detection limits (0.005-0.012 mg/g) without the need for extract evaporation. Under the optimum conditions, recoveries in samples ranged between about 82.6 and 98.7%. Compared to the reference method, the proposed method is simple and rapid, delivering accurate and precise results, and can be applied for routine determination of diphenylamine and its derivatives in propellants. The precision of the method, expressed as relative standard deviation, was about 4.3-10.9%.

Simultaneous determination of diphenylamine and nitrosodiphenylamine by photochemically induced fluorescence and synchronous fluorimetry using double scans method

A new synchronous fluorimetry in the combination with the photochemically induced fluorescence (PIF) method for simultaneous determination of nitrosodiphenylamine (NDPhA) and diphenylamine (DPhA) in aqueous and methanolic solution has been proposed. DPhA has a variety of applications and NDPhA is carcinogenic product of its. The method is based on the use of UV irradiation to produce fluorescent derivatives from NDPhA as a non-fluorescent molecule. The PIF properties of these amines in three media (water, methanol and acetonitrile) are reported. Because of their similar features, the fluorescence emission spectra of NDPhA photoproducts and DPhA were found to severely overlap in the whole wavelength region. Overlapping of conventional fluorescence spectra of these molecules is resolved by synchronous fluorometry using double scans method (SF-DS), thus making the use of separation techniques unnecessary for simultaneous determination of NDPhA and DPhA. The synchronous fluorescence intensity of NDPhA was measured at Δλ of 127 nm and at Δλ=75 nm for DPhA in solution, which are independent of each other. The best sensitivity can be achieved in water. The linear ranges for determination of NDPhA and DPhA were 1 × 10(-8) to 6 × 10(-6)molL(-1) and 4 × 10(-8) to 9 × 10(-6)molL(-1), and the limits of detection (LOD) were 8×10(-9) and 1 × 10(-8)molL(-1), respectively. The relative standard deviations (R.S.D.) of method is<3% (n=5). The proposed method was successfully applied for the determination of the two compounds in synthetic solutions, well water samples and also in gunpowder samples. The results obtained were favorably compared to those obtained with HPLC analysis.

ChemInform Abstract: Determination of Diphenylamine in Contaminated Air of Agricultural Buildings Using Active Sampling on Solid Sorbents

AbstractReview: 35 refs.