Determination Of Aniline Research Articles

Improved selectivity of electrochemical aniline sensing using one-dimensional silver nanorods with high aspect ratio synthesized by ascorbic acid assisted method

BackgroundAniline serves as a pivotal precursor in many industries such as pesticides, pharmaceuticals, and chemicals. However, its ingestion can lead to severe health consequences, including the potential to induce cancer, respiratory tract irritation, and adverse effects on the nervous and digestive systems in the human body. The widespread use of aniline in industrial processes, coupled with inadequate wastewater management that allows for the direct release of aniline into the environment, leads to surface and groundwater contamination. Therefore, it becomes crucial to devise a reliable electrochemical sensor capable of detecting even trace amounts of aniline. ResultsThis study presents a modified polyol synthesis method for producing silver nanorods (AgNRs, length: 861–1345 nm, diameter: 66–107 nm) with preferential growth along the (111) crystal plane. Immobilizing AgNRs on a glassy carbon (GC) electrode with Nafion as a binder decreases its charge transfer resistance from 3040 to 129 kΩ and increases its electroactive area from 0.034 to 0.101 cm2. AgNRs/GC electrode exhibited an aniline detection limit of 0.032 μM and sensitivity of 1.4841 μA.M−1cm−2 within a linear range of 0–10 μM using square wave voltammetry (SWV). The reaction rate constant of aniline sensing was determined to be 0.08697 s−1. Chlorobenzene, acephate, and chlorpyrifos could not interfere aniline detection, and 26 % decrease in peak response was observed after the 10th cycle of aniline sensing. The sensor demonstrated ∼100 % recovery for aniline, comparable to the performance of high-performance liquid chromatography when applied to real-world samples like tap and river water. SignificanceThe electrochemical sensing of aniline is notably efficient in tap and river water within the acceptable limit, by utilizing one dimensional AgNRs functionalized GC electrode. Importantly, the presence of interferents does not compromise the sensitivity of the sensor. Therefore, one dimensional AgNRs synthesized via a modified polyol route emerge as a promising electrocatalyst for the in-situ detection and determination of aniline.

Electrochemical sensing of aniline based on bio-inspired cauliflower shaped tin-oxide nanoparticle using Solanum trilobatum leaf extract

The quantitative detection and determination of aniline (AN) in water samples are of significant importance due to its potential to induce adverse effects in humans and other livestock when consumed in excess. Therefore, it is the need of the hour to develop a highly sensitive conductive matrix for the electrochemical detection and quantification of AN in-water samples. In this regard, tin oxide nanoparticles (SnO2 NPs) were synthesized using Solanum trilobatum leaf extract for the first time. Upon conducting structural analysis of the synthesized SnO2 NPs, aggregates of spherical nanoparticles were observed, resulting in the formation of a cauliflower-like structural morphology. Subsequently, the cauliflower-shaped SnO2 nanoparticles were drop-casted onto the surface of a screen-printed carbon electrode using nafion as a binder, thereby developing an electrochemical sensing platform for the detection of AN. Later, differential pulse voltammetry technique was employed to detect AN over a concentration range of 2.0–14.0 nM, with a limit of detection of 0.897 nM based on the signal-to-noise ratio (S/N = 3). Importantly, the sensing of AN remained unaffected by tested interfering species from various pollutants, as confirmed by recovery values (99.2–101.0%) in water samples. These results collectively demonstrate that the newly designed sensor exhibits good selectivity, sensitivity, and reproducibility for the detection of AN.

Determination of Aniline, 4-Aminoazobenzene, and 2-Naphthol in the Color Additive D&C Red No. 17 Using Ultra-High-Performance Liquid Chromatography.

Specifications in the U.S. Code of Federal Regulations for the color additive D&C Red No. 17 (R17, Colour Index No. 26100) limit the levels of the dye's intermediates, aniline (AN), 2-naphthol (β-naphthol, BN), and 4-aminoazobenzene (4AAB), to 0.2, 0.2, and 0.1%, respectively. The present work reports the development and application of an ultra-HPLC method for the quantitative determination of these impurities in R17. A 1.7 μm particle size C-18 column was used with 0.2 M ammonium acetate and acetonitrile as the eluents. AN, BN, and 4AAB were quantified by using six-point calibration curves with data points (w/w) ranging from 0.01 to 0.25% for AN, 0.01 to 0.24% for BN, and 0.01 to 0.19% for 4AAB. The correlation coefficients ranged from 0.9992 to 0.9999. Limits of detection for the analytes ranged from 0.002 to 0.01%. Recoveries of the analytes ranged from 99.5 to 102%. Relative standard deviations ranged from 0.482 to 1.262%. The new method was applied to analyze portions from 22 batches of R17 submitted to the U.S. Food and Drug Administration for certification. It was found to be simpler to implement, faster, and more sensitive than the older gravity-elution column chromatography method, which it has replaced.

Determination of aniline and quinoline compounds in textiles

A simple method for simultaneous determination of twenty-one analytes, belonging to two classes of compounds, aromatic amines and quinolines, is presented. Several of the analytes considered in this study frequently occur in textiles goods on the open market and have been related to allergic contact dermatitis and/or are proven or suspected carcinogens. The method includes an efficient clean-up step using graphitized carbon black (GCB) that simplifies and improves the robustness of the subsequent GC–MS analysis. Briefly, after solvent extraction of the textile sample, the extract is passed through a GCB SPE cartridge that selectively retain dyes and other interfering compounds present in the matrix, producing a clean extract, suitable for GC–MS analysis, is obtained.The method was evaluated by spiking blank textiles with the selected analytes. Method quantification limits (MQL) ranged from 5 to 720ng/g depending on the analyte. The linear range of the calibration curves ranged over two order magnitude with coefficients of determination (R2) higher than 0.99. Recoveries ranged from 70 to 92% with RSDs 1.7–14%. The effectiveness of the method was tested on a variety of textile materials samples from different origin.In a pilot explorative survey, 2,6-dichloro-4-nitroaniline was detected in all the analysed clothing samples in concentrations ranging from 1.0 to 576μg/g. 2,4-dinitroaniline was detected in four of the seven samples with a highest concentration of 305μg/g. Quinoline was detected in all samples in concentrations ranging from 0.06 to 6.2μg/g.

Quality control in extended measurement campaigns: selection of contract laboratories by proficiency testing exemplified for the trace analysis of anilines in groundwater

An interlaboratory comparison for the determination of aniline, nine methylated anilines and chlorinated anilines in contaminated groundwater (each compound between 1 µg L−1 and 750 µg L−1) was conducted as proficiency test for the selection of contract laboratories for a groundwater monitoring campaign. For the 13 participants, two different test sample series were prepared from a stabilized real case groundwater. Series A was the groundwater as sampled in the field and series B was prepared from series A by spiking with selected anilines. Homogeneity and stability investigations revealed that contaminated groundwater provides a viable basis for the preparation of ring test samples for the determination of anilines. Analytical procedures were limited to the standardized liquid–liquid extraction or solid-phase extraction in combination with gas chromatography/mass spectrometry (DIN 38407-16:1999). The robust consensus values were evaluated according to the standardized protocol of DIN 38402-45:2013. Robust reproducibility standard deviations ranged largely between 20 % and 60 % depending on the analyte. The proficiency assessment of individual participants combined the qualitative aspect of correct peak identification with the quantitative determination of individual concentrations within set limits in a unified approach. It could be shown that the accreditation status of laboratory and the existence of a standardized analytical procedure do not substitute a problem-related proficiency assessment of potential contractors.

Determination of aniline in water and fish by liquid chromatography-tandem mass spectrometry

A fast analytical method for the determination of aniline in water and fish meat by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed. The water sample was mixed with acetonitrile by 4:1 (v/v) and the fish sample was extracted by 2.00 mL acetonitrile for each gram of sample, and then the extracts of water and fish samples were centrifuged at 5,000 r/min for 5 min. The separation was performed on a reversed-phase C18 column using mobile phases of acetonitrile-0.5% (v/v) formic acid aqueous solution (85:15, v/v). Aniline was separated within 3 min. The calibration curve was linear in the range of 0.5-500 pg/L with R2 > 0.999. The limits of detection (LODs) were 0.50 μg/L and 1.00 μg/kg and the limits of quantification (LOQs) were 1.00 μg/L and 2.00 μg/kg for aniline in water and fish meat, respectively. The average recoveries of aniline in water were 93.7% at the spiked level of 40 ng and 86.7% at the spiked level of 400 ng (n = 5). The average recoveries of aniline in fish were 96.8%, 92.6% and 81.8% at the spiked levels of 5, 50 and 500 ng respectively (n = 5). The relative standard deviations were 1.5%-9.2%. Thirteen water samples and twelve fish samples were collected from a reservoir polluted by aniline and the maximum contents found were 1,943. 6 μg/L in water and 60.8 μg/kg in fish. The method is suitable for the determination of aniline residues in water and fish with the characteristics of easy operation, high accuracy and precision.

Determination of Aromatic Amines in Wastewater by Dispersive Liquid-Liquid Microextraction Coupled to Capillary Gas Chromatography

A simple and reliable method combining dispersive liquid-liquid microextracion (DLLME) with gas chromatography (GC) using flame ionization detection (FID) was developed for the simultaneous determination of aniline (AL),o-toluidine (o-TLD),N,N-dimethylaniline (N,N-DAL),p-chloroaniline (p-CAL), andp-nitroaniline (p-NAL) in wastewater. For this purpose, dispersive liquid-liquid microextraction (DLLME) was applied as a sample preparation technique. The DLLME conditions such as the types and volume of extraction solvent, the types and volume of the disperser solvent, pH value and salt addition were studied and optimized. The method was linear in the ranges from 2.2×10-3to 100.0 μg·mL-1for aforementioned aromatic amines withR2≥ 0.9968. The DLLME procedure allowed efficient recovery of the investigated aromatic amines ranging between 82 % and 92 % with a relative standard deviation (RSD) ≤ 3.4 for actual wastewater samples spiked with 5, 10 and 20 μg·mL-1of aromatic amines, respectively. These results showed the potential of this technique for aromatic amines monitoring in wastewater samples. Furthermore, the investigated methods are simple, reproducible, and inexpensive.

Determination of Anilines and Toluidines in Water by Salt-Assisted Dispersive Liquid–Liquid Microextraction Combined with GC-FID

Dispersive liquid–liquid microextraction (DLLME) assisted with salting-out was applied for the determination of five aromatic amines in water samples by using gas chromatography with flame ionization detection. In this extraction method, several factors influencing the extraction efficiency of the target analytes, such as extraction and disperser solvent type and their volume, salt addition and amount, and pH, were studied and optimized. Under the optimal DLLME conditions, good linearity was observed in the range of 4–1,000 ng mL−1 with the RSDs from 1.2 to 7.9 %. The LODs based on S/N of 3 ranged from 0.2 to 3.4 ng mL−1 and the enrichment factors ranged from 207 to 4,315. The proposed method was successfully applied to the water samples collected from the tap and the lake, and the relative recoveries were in the range of 87.7–108.4 %.

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY DETERMINATION OF ANILINES WITH FLUORESCENT DETECTION AND PRE-COLUMN DERIVATIZATION

A simple, sensitive, and rapid reverse-phase high-performance liquid chromatography (RP-HPLC) method for the determination of anilines in water is proposed. The use of 2,7-diethylamino-2-oxo-2H-chromen-3-yl-benzothiazole-6-sulfonylchloride (coumarin 6-SO2Cl) as a fluorigenic-labeling reagent was investigated. The label reacted with aniline within 30 min under mild conditions (ambient temperature, pH 9.0) to give sulfonamides that were separated by RP-HPLC employing fluorescence detection with an excitation wavelength of 470 nm and an emission wavelength of 520 nm. The optimum conditions for fluorescence, derivatization, and chromatographic separation were established. The calibration curves were linear for the range 0–800 ppb. The proposed method was applied for the determination of anilines in spiked drinking water samples and irrigation water samples with recoveries of 90.0–103.9% and relative standard deviations of 1.2–4.7%, respectively. This method showed good accuracy and repeatability that can be used for the quantification of aniline in real samples.

Differential kinetic thermal lens determination of aniline and 4-nitroaniline

Thermal lens spectrometry was used for the differential kinetic determination of aniline (over the concentration range of 8 × 10−4–3.2 × 10−3 M) and 4-nitroaniline (2 × 10−4–1.6 × 10−3 M) present in combination in a single sample based on the oxidation reaction with periodate ions in an acidic medium (this determination is not possible with the spectrophotometric monitoring of the rate of reaction). The thermal lens procedure (λe = 488.0 nm; 80 mW) was characterized by good performance characteristics in the determination of aniline (cmin = 3 × 10−4 M; cd = 8 × 10−4 M) and 4-nitroaniline (cmin = 7 × 10−5 M; cd = 2 × 10−4 M), simplicity, and rapidity.

A fluorescence quenching-based sensor using new metallo-tetraazaporphyrin dye as a recognition element for aniline assay in aqueous solutions

Determination of aniline using metallo-tetraazaporphyrin dyes in CH 2Cl 2 solutions is described. Seven newly synthesized dyes were screened for the purpose. It was found that fluorescence emission between 700 and 800 nm of the new metal complex dye, octakis(methylthio)tetraazaporphyrinzinc(II) at λ max 505 nm excitation was effectively quenched by the presence of aniline at submicromolar concentrations. The magnitude of quenching depended linearly upon the concentration of aniline in the investigated concentration range of 5.32 × 10 −7 to 2.66 × 10 −6 M. Therefore it was used in the determination of aniline in the CH 2Cl 2 extracts from the spiked aqueous solutions. Interference by the other metal ions at 10 and 100 fold higher concentrations in the aqueous solutions was also investigated. The reported method is highly sensitive and showed very low detection limit of 9.87 × 10 −8 M in CH 2Cl 2 solution that corresponded to 1.06 × 10 −7 M aniline in water samples containing micromolar amounts of interfering metal ions. Despite of the simplicity of the method it gave highly reproducible results.

Determination of aniline and phenol in waters using polyurethane foams and diffuse reflectance spectroscopy

The adsorption of aniline as its 4-nitrophenylazo derivative was studied on polyurethane foams depending on phase contact time, reagent concentration, and type of adsorbent. Procedures were developed for the adsorption-photometric determination of aniline and aniline and phenol on their simultaneous presence; they allow the determination of 0.005 μg/mL of aniline.

Determination of aniline in silica gel sorbent by one-step in situ microwave-assisted desorption coupled to headspace solid-phase microextraction and GC–FID

Microwave-assisted desorption (MAD) coupled to in situ headspace solid-phase microextraction (HS–SPME) was first proposed as a possible alternative pretreatment of samples in absorbent collected from workplace monitoring. Aniline collected on silica gel was investigated. Under microwave irradiation, the aniline was desorbed from silica gel and directly absorbed onto the SPME fiber in the headspace. Having been sampled on the SPME fiber, and desorbed in the GC injection port, aniline was analyzed using a GC–FID system. Parameters that affect the proposed extraction efficiency, including the extraction media and its pH, the microwave irradiation power and the irradiation time as well as desorption parameters of the GC injector, were investigated. Experimental results revealed that the extraction of a 150-mg silica gel sample using a 0.8-ml aqueous solution (pH 12) and a PDMS/DVB fiber under medium-high-powered irradiation (345W) for 3min maximized the efficiency of extraction. Desorption of aniline from the SPME fiber was optimal at 230°C held for 3min. The detection limit was 0.09ng. The proposed method provided a simple, fast, and organic solvent-free procedure to analyze aniline from a silica gel matrix.

Determination of Aniline in Water by Microwave-Assisted Headspace Solid-Phase Microextraction and Gas Chromatography

Determination of aniline in wastewater was investigated by microwave-assisted headspace solid-phase microextraction (MA-HS-SPME), for one-step in-situ sample preparation, and gas chromatography. Aniline in the water was evaporated into the headspace under the action of microwave irradiation and adsorbed directly by the SPME fiber. After desorption in the GC injection port and gas chromatography aniline was detected by FID. Conditions affecting the extraction efficiency, for example the pH of the water, addition of salt, microwave power and irradiation time, and desorption conditions were investigated. Experimental results indicated that adjustment of the pH of the water sample to 12 and headspace SPME sampling with a PDMS-DVB fiber under medium–high power irradiation (345 W) for 3 min resulted in the best extraction efficiency. Desorption of aniline was optimum when the SPME fiber was heated at 230 °C for 3 min. The detection limit was approximately 0.01 μg mL−1. The proposed method is a simple, fast, and organic-solvent-free procedure for analysis of aniline in water. Application was illustrated by analysis of aniline in wastewater from a polymer factory.

Flow-injection determination of amine contaminants in cyclamate samples based on temperature for controlling selectivity.

This paper describes a flow-injection (FI) method for the simultaneous determination of aniline and cyclohexylamine impurities in cyclamate products. The method consists of the derivatization of amines with 1,2-naphthoquinone-4-sulfonate under selective and non-selective conditions. Here, the selectivity is achieved by working at 20 degree C, at which only aniline reacts, whilst higher temperatures (80 degree C) lead to a non-selective reaction of the two analytes. The FI manifold is composed of two flow cells for the spectrophotometric detection of derivatives at 480 nm. Experimental conditions have been optimized by factorial design and multicriteria making approach. Quantification is accomplished by differential analysis of the analyte contributions in the double peaks generated when the sample reaches cell 1 and cell 2. Results obtained with the proposed method are in satisfactory agreement with those provided by the standard method for the analysis of cyclamate samples.

Determination of aniline and related mono-aromatic amines in indoor air in selected Canadian residences by a modified thermal desorption GC/MS method

A modified thermal desorption method to determine low levels of aniline and other related mono-aromatic amines (MAAs) in residential air is described. The method was successfully applied to the determination of levels of these chemicals in residential air from 69 selected homes in two Canadian regions. Instrument detection limits of between 0.02 and 0.06 ng per thermal desorption tube were achieved for aniline and other MAAs. In the absence of environmental tobacco smoke (ETS) the mean concentrations of aniline in both indoor air and outdoor air were similar, at about 0.01 μg/m 3 after correction with field blanks. There was however a statistically significant difference in aniline concentrations between field blanks and indoor or outdoor air samples. No significant difference of aniline levels in the two study regions was observed. A clear link between aniline concentrations in indoor air and smoking activities inside homes was evident. Analysis of cigarette leaves indicated that aniline was most likely formed due to combustion during smoking. Shoe polishing was identified as another source of aniline in indoor air.

Spectrophotometric Determination of Aniline in Polluted Surface Water and Wastewater – Improved Reagents in Test Kit Format

A practical test kit based on diazotization reaction of aromatic amines followed by coupling with 2-methyl-8-hydroxyquinoline has been developed to determine trace aniline in wastewater and surface water samples. The test kit consists of four tablets, which are added to the sample in sequence. The maximum absorption wavelength of the orange dye formed is 482 nm. Molar absorptivity and detection limit were found to be 2.5 × 104 Lmol−1cm−1 and 0.020mgL−1, respectively. Linearity was excellent in the concentration range 0.10–3.5 mg L−1 aniline in water. The test kit has been used to analyze aniline in polluted river water and wastewater samples from a pharmaceutical factory. The recoveries of addition of aniline in real water samples were between 95–106% (n=5) and relative standard deviation was less than 5% for standard sample at a concentration of 2.0 mgL−1 aniline. It's a very sensitive and easy-to-operate method for in situ analysis of aniline in water.

A New Spectrophotometry Method for the Determination of Aniline in Environmental Water Samples

ABSTRACT A new spectrophotometric method has been established to determine trace aniline in water samples. A mixture solution of N-chlorosuccinimide and 8-hydroxyquinaldine in N, N-dimethylformamide (DMF) was used to react with the aniline in water at room temperature (20°C). When the solution was adjusted to pH 10-11 by adding 3 mol/L NaOH, a clear and blue-colored dye formed immediately with the maximum absorption wavelength at 615 nm. Molar absorptivity and detection limit were found to be 1.0×104 L mol−1 cm −1 and 30 μg/L, respectively. Linearity was excellent in the concentration range of 0.2 to 15 mg/L aniline in water sample. The proposed method has been used to analyze aniline in surface and sewage water samples with the recoveries 96-103% and relative standard deviation less than 3%. It's a promising method to be applied for routine analysis of aniline in water.

A comparison of chemometric methods for the flow injection simultaneous spectrophotometric determination of aniline and cyclohexylamine

A flow injection spectrophotometric method for the simultaneous determination of aniline and cyclohexylamine using multivariate calibration methods is proposed. The method is based on the reaction of these amines with 1,2-naphthoquinone-4-sulfonate, yielding spectrophotometrically active derivatives. The data analysed with multivariate calibration methods consisted of the spectra registered in the range 290–590 nm at the maximum of the flow injection peak. Although the spectrum of each derivative was characteristic, overlapping occurred and no selective wavelengths were found. The predictive abilities of principal component regression and partial least-squares regression (PLS), non-linear PLS, locally weighted regression (LWR) and artificial neural networks were examined for the determination of aniline and cyclohexylamine in sample mixtures. The accuracy for cyclohexylamine and aniline quantifications in unknown mixtures was optimum with LWR, providing overall prediction errors of 3.4 and 5.6%, respectively.

In-vial liquid-liquid extraction with subsequent large-volume on-column injection into gc-ms for the determination of anilines in tap, surface, and wastewater

In-vial liquid-liquid extraction with subsequent large-volume on-column injection into gc-ms for the determination of anilines in tap, surface, and wastewater