4-aminoantipyrine Method Research Articles

Validation of a smartphone-compatible MIP-based sensor for bisphenol A determination in wastewater samples.

A handheld smartphone-compatible molecularly imprinted polymer (MIP)-based sensor was developed for the analysis of bisphenol A (BPA) in wastewater samples. Sensing elements based on ethylene glycol methacrylate phosphate (EGMP)-containing MIP films were designed and optimized using molecular dynamics simulations. The highly porous MIP films were synthesized via in situ polymerization, employing a fragment-based approach. The colorimetric response was based on the 4-aminoantipyrine method, while the MIP films were further utilized to detect BPA with a smartphone. The proposed sensor exhibited a wide linear range from 5 to 250μM, with a limit of detection (LOD) of 5μM (S/N = 3). Furthermore, the designed analytical system demonstrated excellent analytical performance in terms of selectivity, stability, and reproducibility. During sensor validation, real wastewater samples were successfully tested for BPA, showcasing the feasibility of the smartphone-compatible MIP-based sensor. Recovery values of 87.1-114.6% underscored the efficacy and reliability of the developed sensor system.

Colorimetric analysis based on solid-phase extraction with sedimentable dispersed particulates: demonstration of concept and application for on-site environmental water analysis.

A novel simple and functional colorimetric methodology for on-site environmental water analysis was proposed. This method combines coloration of the analyte and extraction of the colored species on dispersed particulates during their sedimentation in the same container. The whole analysis can be performed within 15 min by comprising the addition of 1 mL of sample solution into a 1.5-mL microtube containing the powders of coloring reagents and the sedimentable fine particulates as an adsorbent. The analyte is determined by comparing the sediment color with the standard color by visual inspection or the color information of the photo image. The potential of this methodology was demonstrated through developing colorimetry for Fe2+ with o-phenanthroline, NO2- by azo-dye formation, HCHO by the MBTH method, and PO43- by the 4-aminoantipyrine method based on the enzyme reactions. The material, size, amount of the adsorbent particles, and other conditions were optimized for each analytes. The advantages of the methodology were as follows: high sensitivity, easy controllability of the sensitivity over the wide range by the amount, size, and material of the particulates, lower interference from the colored matrix components due to obtaining the color data from not the aqueous phase but the sedimented particulates, and acceleration of the color development rate by the particulates as seen in NO2- determination as consequence shorten the operation time. A simple device equipped with twin cells was proposed for on-site analysis which contains two successive different coloring operations. The developed methods were successfully applied to the environmental water samples with the good agreement of the results with those by the usual instrumental methods.

EFFECT OF TEMPERATURE AND PH ON PHENOL BIODEGRADATION BY A NEWLY IDENTIFIED SERRATIA SP. AQ5-03

Phenol is mainly used by the industries to produce a variety of chemical products such as resins, textiles, pesticides, plastics and explosive. The wide use of phenol and other phenolic compounds by industries, has resulted in an increased presence of these toxic compounds in the environment as pollutants. Bio-removal of phenol by microorganisms especially bacteria has been demonstrated to be the most effective and economical approach compared to physio-chemical methods. The search for efficient phenol-degraders especially local sources to remediate local phenol pollution is important as indigenous bacteria usually have better survival and resilient to local geographical conditions. In this study, a phenol-degrading microorganism was isolated from local soil and waste water bodies. Identification was carried out using gram staining, 16s rRNA gene sequencing and molecular phylogeny analysis using the Phylip software. The isolates were inoculated in mineral salt media with 0.5 g/L phenol as the sole source of carbon. Phenol degradation was determined using 4-amino antipyrine method. Physical and cultural conditions influencing phenol degradation such as pH and temperature were optimized via one-factor-at-a-time. Through phylogeny analysis, the isolate was identified as Serratia sp. and the sequence was deposited the NCBI Genebank and accession number KT693287 was assigned to the bacteria. The highest degradation was achieved at pH 7.5 (phosphate buffer) and temperature of 30°C. Ammonium sulphate was established to be the best nitrogen source at the concentration of 0.4 g/L and a sodium chloride concentration of 0.15 g/L.
 Aisami, A. | Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, Selangor, Malaysia

Flow effects on phenol degradation and sonoluminescence at different ultrasonic frequencies.

Current literature shows a direct correlation between the sonochemical (SC) process of iodide oxidation and the degradation of phenol solution. This implies phenol degradation occurs primarily via oxidisation at the bubble surface. There is no work at present which considers the effect of fluid flow on the degradation process. In this work, parametric analysis of the degradation of 0.1mM phenol solution and iodide dosimetry under flow conditions was undertaken to determine the effect of flow. Frequencies of 44, 300 and 1000kHz and flow rates of 0, 24, 228 and 626mL/min were applied with variation of power input, air concentration, and surface stabilisation. Phenol degradation was analysed using the 4-aminoantipyrine (4-AAP) method, and sonoluminescence (SL) images were evaluated for 0.1, 20 and 60mM phenol solutions. Flow, at all frequencies under certain conditions, could augment phenol degradation. At 300kHz there was excellent correlation between phenol degradation and dosimetry indicating a SC process, here flow acted to increase bubble transience, fragmentation and radical transfer to solution. At 300kHz, although oxidation is the primary phenol degradation mechanism, it is limited, attributed to degradation intermediates which reduce OH radical availability and bubble collapse intensity. For 44 and 1000kHz there was poor correlation between the two SC processes. At 44kHz (0.01mM), there was little to suggest high levels of intermediate production, therefore it was theorised that under more transient bubble conditions additional pyrolytic degradation occurs inside the bubbles via diffusion/nanodroplet injection mechanisms. At 1000kHz, phenol degradation was maximised above all other systems attributed to increased numbers of active bubbles combined with the nature of the ultrasonic field. SL quenching, by phenol, was reduced in flow systems for the 20 and 60mM phenol solutions. Here, where the standing wave field was reinforced, and bubble localisation increased, flow and the intrinsic properties of phenol acted to reduce coalescence/clustering. Further, at these higher concentrations, and in flow conditions, the accumulation of volatile phenol degradation products inside the bubbles are likely reduced leading to an increase SL.

CORRELATION BETWEEN BLOOD METABOLITE AND REPRODUCTIVE PERFORMANCE OF LACTATING HOLSTEIN FRIESIAN CROSSBRED COWS IN SMALLHOLDER FARMERS

This study examined the correlation between the concentration of blood metabolites (triglyceride, albumin, phosphorous) on the reproductive performances (S/C and PPM) of lactating Holstein Friesian crossbred (HFC) cows. Blood samples were collected through the caudal vein 8 hours after feeding and the plasma was analyzed at the Integrated Research and Testing Laboratory of Universitas Gadjah Mada (LPPT UGM). Samples were stored at 5° C. Triglyceride, albumin, and phosphorous were measured using glucose oxidase-phenol 4-aminoantipyrine (GOD-PAP) method, photometric bromocresol green method, and cypress diagnostic, respectively. Blood metabolites data were analyzed using Pearson correlation model. The results showed that the correlation coefficients of triglycerides, albumin, and phosphorus levels on PPM and S/C were -0.521 and -0.650; -0.447 and -0.612; -0.513 and -0.700, respectively. In conclusion, there are significant negative correlation between triglyceride, albumin and phosphorus levels on the PPM, and very significant negative correlation between triglyceride, albumin and phosphorus levels on the S/C of lactating HFC cows.

Integrated Microcentrifuge Carbon Entrapped Glucose Oxidase Poly (N-Isopropylacrylamide) (pNIPAm) Microgels for Glucose Amperometric Detection

This study demonstrates a miniaturized integrated glucose biosensor based on a carbon microbeads entrapped by glucose oxidase (GOx) immobilized on poly (N-isopropylacrylamide) (pNIPAm) microgels. Determined by the Lowry protein assay, the pNIPAm microgel possesses a high enzyme loading capacity of 31 mg/g. The pNIPAm GOx loaded on the microgel was found to maintain a high activity of approximately 0.140 U determined using the 4-aminoantipyrine colorimetric method. The integrated microelectrochemical cell was constructed using a microcentrifuge vial housing packed with (1:1, w/w) carbon entrapped by pNIPAm GOx microgels, which played the dual role of the microbioreactor and the working electrode. The microcentrifuge vial cover was used as a miniaturized reference electrode and an auxiliary electrode holder. The device can work as biosensor, effectively converting glucose to H2O2, with subsequent amperometric detection at an applied potential of −0.4 V. The microelectrochemical biosensor was used to detect glucose in wide linear range from 30 µM to 8.0 mM, a low detection limit of 10 µM, a good linear regression coefficient (R2) of 0.994, and a calibration sensitivity of 0.0388 µA/mM. The surface coverage of active GOx, electron transfer rate constant (ks), and Michaelis–Menten constant (KMapp) of the immobilized GOx were 4.0 × 10−11 mol/cm2, 5.4 s−1, and 0.086 mM, respectively. To demonstrate the applicability and robustness of the biosensor for analysis of high sample matrix environment, glucose was analyzed in root beer. The microelectrochemical device was demonstrated for analysis of small sample (<50 µL), while affording high precision and fast signal measurement (≤5 s).

Demonstration of environmental chemistry with microscale chemistry and a low-cost four-led based photom

&lt;span&gt;In this article, a four-LED based photometer, in which four LEDs are used as light sources, are demonstrated to be a useful instrument for the study of pollution problems caused by phenols and of their remediation by electrochemical degradation method and the iron (II) catalyzed homogeneous Fenton’s reaction. The fate of phenols can be monitored by the photometer via the 4-aminoantipyrine method. The results revealed that the latter method was a superior method to treat the phenolic compounds.&lt;/span&gt;

A study and abatement of phenolic content in waterfrom various sampling points in the vicinity of River Patalganga

Phenolic compounds find out their way in the water bodies as a result of industrial activities along with being synthesized by other natural commotions. The present investigation deals with the study of leaching effect of such phenolic compounds and its abatement by using a range of carbons acquired from nature and activated in the laboratory using ZnCl2. All the water samples were analyzed for Phenolic content by the 4-Amino Antipyrine method and confirmed by the bromination method. The investigation revealed that the phenolic content in the samples varied from a minimum of 0.01ppm to 79.65ppm, which according to WHO was much higher than the permissible levels of 0.2ppm for 2,4,6-trichlorophenols(2,4,6-TCP) and 0.04ppm for 2,4-dichlorophenols (2,4-DCP). 2,4,6-TCP and 2,4-DCP being the two most probable phenolic compounds to occur in drinking water.The rise in the values of phenolic content in the samples of Sawla and Jatada were accredited to the leaching effect of the effluent from the agro and insecticide industry, sited in the proximity of these villages.Abatement of phenolic content was carried out by preparing carbons from Mangifera indica, Saraca asoca, Psidium guajava as well as commercial carbon, which were activated in the laboratory using ZnCl2. Each of the natural carbon exhibiting a distinct capacity of lessening phenolic content.

Aqueous two-phase systems: A new approach for the determination of p-aminophenol

A new method has been developed for the spectrophotometric determination of p-aminophenol (PAP) in water, paracetamol formulations and human urine samples with a recovery rate between 94.9 and 101%. This method exploits an aqueous two-phase system (ATPS) liquid–liquid extraction technique with the reaction of PAP, sodium nitroprusside and hydroxylamine hydrochloride in pH 12.0, which produces the [Fe 2(CN) 10] 10− anion complex that spontaneously concentrates in the top phase of the ATPS ( K [ Fe 2 ( CN ) 10 ] 10 − = 97.7 ). The ATPS does not require an organic solvent, which is a safer and cleaner liquid–liquid extraction technique for the determination of PAP. The linear range of detection was from 5.00 to 500 μg kg −1 ( R ≥ 0.9990; n = 8) with a coefficient of variation of 2.11% ( n = 5). The method exhibited a detection limit of 2.40 μg kg −1 and a quantification limit of 8.00 μg kg −1. The ATPS method showed a recovery that ranged between 96.4 and 103% for the determination of PAP in natural water and wastewater samples, which was in excellent agreement with the results of the standard 4-aminoantipyrine method that was performed on the same samples.

A SENSITIVE SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF DIOSMIN USING SODIUM NITROPRUSSIDE AS A CHROMOGENIC REAGENT

A simple and sensitive method for the spectrophotometric determination of diosmin has been developed, and optimum reaction conditions along with other analytical parameters have been evaluated. Diosmin, as a phenolic compound, reacts with sodium nitroprusside and hydroxylamine hydrochloride in a basic medium to give a green-colored product. At analytical wavelength of 763 nm, Beer's law is obeyed over the concentration range 2–140 μg mL−1 of diosmin with a correlation coefficient of 0.9997. The molar absorptivity is 9671 L mol−1 cm−1. The limits of detection (LOD) and quantification (LOQ) are 0.05 and 0.2. μg mL−1, respectively. The method has been successfully applied to the determination of diosmin in a commercial pharmaceutical preparation. The results were compared favorably with those obtained by the 4-aminoantipyrine method.

Flow system for the automatic screening of the effect of phenolic compounds on the luminol–hydrogen peroxide–peroxidase chemiluminescence system

In this work, an automated flow-based procedure for the screening of the effect of the different phenolic compounds on the chemiluminescence (CL) luminol-hydrogen peroxide-horseradish peroxidase (HRP) system is presented. This procedure involves the combination of multisyringe flow injection analysis (MFSIA) and sequential injection analysis (SIA) techniques and exploits the ability of the different subgroups of phenols, such as cholorophenols, nitrophenols, methylphenols and polyphenols, to enhance or inhibit the described CL system. The implementation of this reaction in the SIA-MSFIA system enabled favourable and precise conditions to evaluate the effect of phenolic compounds, as it involves an in-line reaction between the phenolic derivative, hydrogen peroxide and peroxidase and subsequent oxidized HRP intermediates generation prior to the fast reaction with the chemiluminogenic reagent. Several studies were then performed with the aim of establishing the appropriate flow system configuration and reaction conditions. It was shown that phenol and chlorophenols produce an enhanced CL response and nitrophenols, methylphenols and polyphenols are inhibitors within the range of concentrations studied (1-100 mg/L). Based on these studies, the developed method was applied to the determination of total polyphenol and phenol content in wine/grape seeds and water samples, respectively, and the results obtained showed good agreement with those furnished by the corresponding Folin-Ciocalteu and 4-aminoantipyrine reference methods. The developed approach is further pursued by designing an automated generic tool for performing studies of peroxidase-catalysed CL reactions of luminol focused on the detection of compounds that will affect the rate of those reactions.

A green and sensitive method to determine phenols in water and wastewater samples using an aqueous two-phase system

A greener and more sensitive spectrophotometric procedure has been developed for the determination of phenol and o-cresol that exploits an aqueous two-phase system (ATPS) using a liquid–liquid extraction technique. An ATPS is formed mostly by water and does not require organic solvent. Other ATPS components used in this study were the polymer, polyethylene oxide, and some salts (i.e., Li 2SO 4, Na 2SO 4 or K 2HPO 4 + KOH). The method is based on the reaction between phenol, sodium nitroprusside (NPS) and hydroxylamine hydrochloride (HL) in an alkaline medium (pH 12.0), producing the complex anion [Fe 2(CN) 10] 10− that spontaneously concentrates in the top phase of the system. The linear range was 1.50–500 μg kg −1 ( R ≥ 0.9997; n = 8) with coefficients of variation equal to 0.38% for phenol and 0.30% for o-cresol ( n = 5). The method yielded limits of detection (LODs) of 1.27 and 1.88 μg kg −1 and limits of quantification (LOQs) of 4.22 and 6.28 μg kg −1 for phenol and o-cresol, respectively. Recoveries between 95.7% and 107% were obtained for the determination of phenol in natural water and wastewater samples. In addition, excellent agreement was observed between this new ATPS method and the standard 4-aminoantipyrine (4-AAP) method.

Bioelectrochemical Response of the Polyaniline Tyrosinase Electrode to Phenol

A new, simple amperometric sensor system for detecting phenols has been developed. Using the electrochemical doping method, a polyaniline tyrosinase electrode (TS/PAN/Pt) has been devised as a detecting phenol sensor. The effect of experimental parameters, such as operating potential, pH, and temperature, has been studied. The activation energy of the enzyme-catalyzed reaction is 14.73 kJ mol−1. Comparison of the responses with the 4-aminoantipyrine standard method for phenol sample analysis indicated the feasibility of the TS/PAN/Pt sensor. The TS/PAN/Pt shows a high operational stability. Under the optimum conditions, the TS/PAN/Pt displayed detection limits for phenol in the lower nanomolar range.

Determination of phenols in waters using micro-pumped multicommutation and spectrophotometric detection: an automated alternative to the standard procedure

An automated and greener spectrophotometric procedure has been developed for the determination of phenol in water at 700 nm. The method uses the reaction between phenol, sodium nitroprusside, and hydroxylamine hydrochloride in a buffered medium at pH 12.3. The flow manifold comprises four solenoid micro-pumps employed for sample and reagent introduction into the reaction coil and to transport the colored product formed to the detector. The linear dynamic range was 50-3,500 ng mL(-1) (R = 0.99997; n = 6) and the method provided a limit of detection (3sigma) of 13 ng mL(-1). The sampling throughput was estimated to be 65 measurements per hour and the coefficient of variation was 0.5% (n = 10) for a 1.0 microg mL(-1) phenol concentration. Recoveries of 92-105% were obtained for phenol determination in spiked water samples at concentration levels from 50 to 5,000 ng mL(-1). The use of multicommutation reduced the reagent consumption 25-fold, the sample consumption 225-fold, and the waste generation 30-fold compared with the batch procedure. The proposed method is an environmentally friendly alternative to the official 4-aminoantipyrine method since it avoids the use of chloroform.

The 4-aminoantipyrine Method Revisited: Determination of Trace Phenols by Micellar Assisted Preconcentration

The traditional method for phenol analysis based on the oxidizing coupling of 4-aminoantipyrine (4-APP) with phenol in alkaline solution is re-evaluated in this study in combination with micellar assisted preconcentration (cloud point extraction). The method employs the conventional reaction pathway while extraction is facilitated by surfactant based precipitation, during which the nonpolar derivative of 4-AAP-phenol is entrapped in the micelles and concentrated into a surfactant-rich phase. The latter is the re-solubilized and the complex is quantified spectrophotometrically in the presence of a surfactant. Compared to the traditional method the modification proposed offers certain analytical advantages like massive analysis of many samples, lower detection limits and shorter time of analysis. The method was applied in various samples of different origin with satisfactory results.

Pervaporation-flow injection analysis of phenol after on-line derivatisation to phenyl acetate

A reverse pervaporation-flow injection (rPFI) method coupled with on-line derivatisation was developed for the determination of trace phenol in aqueous samples. On-line rPFI derivatisation was performed by direct injection of acetic anhydride into a donor stream of standard or sample phenol solution, which had been merged upstream with an alkaline concentrated sodium chloride stream. The reaction mixture was passed through a mixing chamber to generate phenyl acetate, which was then transported to the pervaporation unit. After evaporation into the headspace of the pervaporation unit, phenyl acetate diffused through a hydrophobic membrane into a static alkaline solution in the acceptor chamber where it was trapped for 15 min. Phenyl acetate was converted to phenolate ions and then transported to an electrochemical detector where it was analysed amperometrically at a glassy carbon electrode at +0.62 V (versus Ag/AgCl). The calibration plot was linear over the range of 50–1000 μg l −1 with a sample throughput of 4 h −1. The detection limit was determined to be 25 μg l −1 and 4.85% R.S.D. for n=6 (at 1000 μg l −1). This new method was applied to the analysis of several samples and the data compared with those obtained by the standard 4-aminoantipyrine (4-AAP) method and reversed-phase HPLC.

Disposable tyrosinase-peroxidase bi-enzyme sensor for amperometric detection of phenols

A new disposable amperometric bi-enzyme sensor system for detecting phenols has been developed. The phenol sensor developed uses horseradish peroxidase modified screen-printed carbon electrodes (HRP-SPCEs) coupled with immobilized tyrosinase prepared using poly(carbamoylsulfonate) (PCS) hydrogels or a poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ) matrix. Optimization of the experimental parameters has been performed with regard to buffer composition, pH, operating potential and storage stability. A co-operative reaction involving tyrosinase and HRP occurs at a potential of −50 mV versus Ag/AgCl without the requirement for addition of extraneous H 2O 2, thus, resulting in a very simple and efficient system. Comparison of the electrode responses with the 4-aminoantipyrine standard method for phenol sample analysis indicated the feasibility of the disposable sensor system for sensitive ‘in-field’ determination of phenols. The most sensitive system was the tyrosinase immobilized HRP-SPCE using PCS, which displayed detection limits for phenolic compounds in the lower nanomolar range e.g. 2.5 nM phenol, 10 nM catechol and 5 nM p-cresol.

4-Aminoantipyrine spectrophotometric method of phenol analysis: Study of the reaction products via liquid chromatography with diode-array and mass spectrometric detection

The synthesis of new pyrazolone molecules and their application as chromogenic agents in phenol analysis by the 4-aminoantipyrine method has been described by our group in previous published papers. A fully detailed mechanism is given therein based on experimental and theoretical data. In this paper, the study of the reaction products and by-products via liquid chromatography with diode array and mass spectrometric detection is presented, sorting out the spectrophotometric determination of phenols.

Inhibitory Kinetic Fluorimetric Determination of Trace Phenols

An inhibitory kinetic fluorimetric method is reported for the determination of trace phenols. The proposed method is based on the inhibitory effect of phenols on the reaction of H2O2 oxidation of Rh6G catalyzed by Fe(III) in perchloric acid medium. The detection limit for phenol is 8.45 ng/ml. The linear range of the determination is 0.013∼0.192 μg/ml. This method has been successfully used to determine phenols in crude carbolic acid, synthetic samples and industrial wastewaters. A comparison is made between the proposed and the 4-aminoantipyrine (4-AAP) methods. It is found that the method proposed in this paper is superior to the 4-AAP method.

Determination of phenol in water by pervaporation–flow injection analysis

A pervaporation–flow injection method for the determination of phenol in aqueous samples is described. The method involves sample injection into a concentrated sodium chloride (25 wt.%) donor stream at pH 2 and stopping the flow of the acceptor stream containing 0.1 M KNO 3 and 0.01 M NaOH in the acceptor chamber of the pervaporation unit for 12 min. This period allows the completion of phenol transfer from the headspace of the donor chamber of the pervaporation unit through the membrane into the static solution in the acceptor chamber. After restarting the flow through the acceptor chamber the phenol concentration is detected amperometrically at a glassy carbon electrode set at +0.6 V. At 20°C the linear detection range was found to be 1–50 mg l −1 with R.S.D. varying between 1 and 4% for n=3. The detection limit and sample throughput were determined as 0.9 mg l −1 and 5 h −1, respectively. Excellent agreement with the standard 4-aminoantipyrine (4-AAP) method was observed when validating the method with lake samples containing suspension and spiked with phenol.