Determination Of Phenols In Water Research Articles

A new resonance Rayleigh scattering method for phenol based on Cr(III) metal–organic framework probe and 4-aminoantipyrine reaction

Stable Cr(III) metal–organic framework (CrMOF) was prepared and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier infrared spectroscopy (FTIR). It was found that in the presence of potassium periodate (KIO4), phenol (PN) reacted with 4-aminoantipyrine (AAP) to form red quinone imine (QI) product, and a resonance Rayleigh scattering energy transfer (RRS-ET) occurred between the acceptor QI and the donor CrMOF. With the increase of PN concentration, RRS-ET increased, and the RRS intensity at 500 nm decreased. Based on this, a new and simple RRS-ET method for the detection of PN was established, with a detection range of 0.01–0.15 mmol/L and a detection limit (DL) of 0.005 mmol/L. The new RRS-ET method was applied to the determination of PN in water. The relative standard deviation (RSD) was 0.94–7.43%, and the recovery was 97–107%.

Molecularly Imprinted Cellulose Sensor Strips for Selective Determination of Phenols in Aqueous Environment

The surrounding environment is largely contaminated with phenols, and consequently qualitative and quantitative determination of phenols in water is of interest. In the current report, a low cost, naked-eye, portable and disposable cellulosic strips-based sensor was fabricated to detect phenols in aqueous media. The cellulosic filter paper was molecularly imprinted with Fe(III) to prepare strips sensor of Fe(III)-imprinted filter paper. The prepared strips were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis and Fourier-transform infrared spectroscopy. The sensitivity performance of Fe(III)-imprinted filter paper strips was monitored for a series of phenolic compounds. The colorimetric detection of gallic acid was selectively studied herein due to its greatest sensibility. The chromogenic Fe(III)-imprinted filter paper strips provided an instant color shift from yellow to purple upon binding to Gallic acid in an aqueous environment, as visually noted and instrumentally detected by absorption spectral and coloration measurements. The change in color of strips attributing to sensing of Gallic acid was readout at quite low limit (0.1 ppb). This sensor performance was rationalized on formation of coordination complex between phenol and Fe+3. The facile fabricated molecularly imprintedfilter paper strips could be easily used as sensor in rapid potential for colorimetric detection of phenols.

액-액 추출과 아세틸화 후 GC-MS를 이용한 물 중 phenol의 분석

액-액 추출과 아세틸화 후 GC-MS를 이용한 물 중 phenol의 분석

Modifing ASTM standard method by using homogeneous liquid-liquid microextraction combined with fiber optic UV-vis spectrometery for a greener approach to determination of total phenols in water

New developed method based on official American Society for Testing and Materials (ASTM) standard method was used for determining phenolic compounds in water by using homogeneous liquid–liquid extraction (HLLE) and fiber optic-linear array detection spectrometers (FOLADS). HLLE is a method based on phase separation in a ternary solvent system (water-tetrabutylammonium ion, TBA+-chloroform). The phase separation phenomenon occurred by an ion-pair formation of TBA+ and perchlorate ion. The aim of using this method was decreasing volume of extraction solvent used in ASTM standard method. After centrifugation the sediment phase was transferred to a 50-μL cylindrical micro-cell and absorbance was measured at 480 nm. Under the optimum conditions, linearity was obtained in the range of 5.0 to 80.0 μg/L for phenol. Coefficient of correlation (r2) was 0.992. The relative standard deviation was 1% for the analysis of 5 samples with concentration of 50 μg/L of phenol. The limit of detection was 2.0 μg/L. The relative recoveries of phenol in water samples were in the range of 97–104%. The proposed method was successfully applied for determination of phenolic compounds in real water samples.

Microbial trench-based optofluidic system for reagentless determination of phenolic compounds.

Phenolic compounds are one of the main contaminants of soil and water due to their toxicity and persistence in the natural environment. Their presence is commonly determined with bulky and expensive instrumentation (e.g. chromatography systems), requiring sample collection and transport to the laboratory. Sample transport delays data acquisition, postponing potential actions to prevent environmental catastrophes. This article presents a portable, miniaturized, robust and low-cost microbial trench-based optofluidic system for reagentless determination of phenols in water. The optofluidic system is composed of a poly(methyl methacrylate) structure, incorporating polymeric optical elements and miniaturized discrete auxiliary components for optical transduction. An electronic circuit, adapted from a lock-in amplifier, is used for system control and interfering ambient light subtraction. In the trench, genetically modified bacteria are stably entrapped in an alginate hydrogel for quantitative determination of model phenol catechol. Alginate is also acting as a diffusion barrier for compounds present in the sample. Additionally, the superior refractive index of the gel (compared to water) confines the light in the lower level of the chip. Hence, the optical readout of the device is only altered by changes in the trench. Catechol molecules (colorless) in the sample diffuse through the alginate matrix and reach bacteria, which degrade them to a colored compound. The absorbance increase at 450 nm reports the presence of catechol simply, quickly (~10 min) and quantitatively without addition of chemical reagents. This miniaturized, portable and robust optofluidic system opens the possibility for quick and reliable determination of environmental contamination in situ, thus mitigating the effects of accidental spills.

Graphene quantum dots and the resonance light scattering technique for trace analysis of phenol in different water samples

A novel, highly selective resonance light scattering (RLS) method was researched and developed for the analysis of phenol in different types of industrial water. An important aspect of the method involved the use of graphene quantum dots (GQDs), which were initially obtained from the pyrolysis of citric acid dissolved in aqueous solutions. The GQDs in the presence of horseradish peroxidase (HRP) and H2O2 were found to react quantitatively with phenol such that the RLS spectral band (310nm) was quantitatively enhanced as a consequence of the interaction between the GQDs and the quinone formed in the above reaction. It was demonstrated that the novel analytical method had better selectivity and sensitivity for the determination of phenol in water as compared to other analytical methods found in the literature. Thus, trace amounts of phenol were detected over the linear ranges of 6.00×10−8–2.16×10−6M and 2.40×10−6–2.88×10−5M with a detection limit of 2.20×10−8M. In addition, three different spiked waste water samples and two untreated lake water samples were analysed for phenol. Satisfactory results were obtained with the use of the novel, sensitive and rapid RLS method.

Determination of Phenols in Water by Modified Polymer Extraction-Fluorine Derivative Gas Chromatography-Negative Chemical Ionization Mass Spectrometry

Determination of Phenols in Water by Modified Polymer Extraction-Fluorine Derivative Gas Chromatography-Negative Chemical Ionization Mass Spectrometry

[Determination of phenol in water by electrochemical tyrosinase biosensor based on ordered graphitized mesoporous carbon and evaluated by high performance liquid chromatography].

A novel electrochemical tyrosinase biosensor based on ordered graphitized mesoporous carbon (GMC) was obtained, which was used as a platform for phenol detection. The accuracy of tyrosinase biosensor method was comparatively evaluated by high performance liquid chromatography (HPLC). By entrapping tyrosinase molecules (6.5 nm x 9.8 nm x 5.5 nm) into the mesopores of GMC (diameter 10 nm, GMC10), the "interspace confinement effect" of GMC10 may improve the stability of tyrosinase in vitro. After 21-day storage, the GMC10-based tyrosinase biosensor retained more than 85% of its initial response. It is indicated that GMC10 with "interspace confinement effect" can significantly prolong the life of tyrosinase molecules in vitro. Furthermore, the GMC-based tyrosinase biosensor displayed excellent analytical performances for phenol detection, such as stability, repeatability, selectivity, sensitivity and limit of detection. The GMC-based tyrosinase biosensor demonstrated a linear response for phenol from 0. 1 to 10 µmol/L with a low detection limit of 20 nmol/L. The comparative study between HPLC and GMC-based tyrosinase biosensor showed that the detection of phenol in water sample by the GMC-based tyrosinase biosensor method is reliable, accurate and effective. The proposed GMC-based tyrosinase biosensor proved to be a very promising "pre-alarm" tool for rapid detecting phenol pollution in emergency accidents.

A Graphene-Based Electrochemical Sensor for Rapid Determination of Phenols in Water

A glassy carbon electrode (GCE) coated with a graphene/polymer film was fabricated for rapid determination of phenols in aqueous solutions. The electrochemical behavior of different phenols at the graphene/polymer-coated GCE was also investigated. In PBS buffer solution with a pH of 6.5, hydroquinone exhibits a well-defined reduction peak at the modified GCE. Based on this, an electrochemical method for the direct determination of phenols is proposed. Investigating different parameters revealed the optimized detection conditions for the electrode are a scan rate of 50 mV/s, dosage of graphene-polyaniline of 8 μL, dosage of tyrosinase of 3 μL, and pH of 6.5. Under the optimal conditions, the reduction peak current varies linearly with the concentration of phenols, with a linear regression equation of I (10−6A) = −4.887 × 10−4C (mol/L)−5.331 × 10−6 with a correlation coefficient of 0.9963 and limit of detection (S/N = 3) of 2.00 × 10−4 mol/L. The electrochemical sensor is also used to detect phenols in actual samples, where it shows great promise for rapid, simple and quantitative detection of phenols.

Determination of methyl-substituted phenols in water by gas chromatography with preliminary iodination

A procedure is developed for determining phenol; 2-, 3-, and 4-methylphenols, and 2,4- and 2,6-dimethylphenols in aqueous media, which consists in the synthesis of iodine derivatives, their extraction with toluene, and determination by gas chromatography with electron-capture detection. The optimal conditions for the iodination of phenols in water are found; also the extraction and gas chromatography behavior of methylphenols and their iododerivatives are investigated. To make the identification of iododerivatives of methylphenols more reliable, they are subjected to acylation with acetic anhydride in the extract. The analytical range of phenols in water is 0.01–10 μg/L, the relative standard deviation is 2–6%, and the duration of analysis is up to 40 min.

Magnetically confined hydrophobic nanoparticles for the microextraction of endocrine-disrupting phenols from environmental waters

In this article, a solid-phase extraction approach, which takes advantage of the good extraction capabilities of hydrophobic magnetic nanoparticles (MNPs), is presented. The new approach involves the deposition of a thin layer of MNPs in a dedicated stirring unit based on the dual function of a mini-magnet. The system allows the extraction of the analytes in a simple and efficient way. The approach, which reduces the negative effect of the aggregation tendency of hydrophobic MNPs, is characterized for the resolution of a model analytical problem: the determination of some endocrine-disrupting phenols in water by liquid chromatography-photometric detection. All the variables involved in the extraction process have been clearly identified and optimized. The new extraction mode allows the determination of these compounds with limits of detection in the range from 0.15 μg/L (for 4-tert-octylphenol) to 2.7 μg/L (for 4-tert-butylphenol) with a relative standard deviation lower than 5.3 % (for 4-tert-butylphenol).

Biomimetic enhanced chemiluminescence of luminol–H2O2 system by manganese (III) deuteroporphyrin and its application in flow injection determination of phenol at trace level

Abstract A novel, sensitive and high selective flow-injection chemiluminescence (FI-CL) method for the determination of phenol is reported, based upon its decreasing effect on the CL reaction of luminol with hydrogen peroxide catalyzed by manganese (III) deuteroporphyrin [MnDP, Scheme 1 , 3] in alkaline solution. Under the selected optimized experimental conditions, the relative CL intensity was linear with phenol in the range of 4.0 × 10−9 to 4.0 × 10−7 g mL−1. The detection limit (3σ) was 6.3 × 10−10 g mL−1 and the relative standard deviation for 1.0 × 10−7 g mL−1 phenol (n = 11) was 2.99%. The regression equation was I = 120.79 + 1.14 × 1010c (R = 0.9936). This method has been applied to the determination of phenol in water with satisfactory results.

Determination of phenols in waters by stir membrane liquid–liquid–liquid microextraction coupled to liquid chromatography with ultraviolet detection

A simple and rapid method for the determination of eleven phenols in water samples is presented. The target analytes are isolated by stir membrane liquid–liquid microextraction working under the three-phase mode. An alkaline aqueous solution is used as extractant phase while octanol is selected as supported liquid membrane solvent. The target analytes are separated and determined by liquid chromatography (LC) with ultraviolet detection (UV). All the variables involved in the extraction process have been studied in depth. Low detection limits (in the range from 82.1 ng/L for phenol to 452 ng/L for 2,4,5-trichlorophenol) were obtained. The repeatability, expressed as relative standard deviation (RSD), varied between 1.3% (for 4-nitrophenol) and 8.0% (for 4-chlorophenol). The enrichment factors were in the range from 168 (for 2,4,5-trichlorophenol) to 395 (for 3-chlorophenol). The proposed procedure was applied for the direct determination of the eleven phenols in some real water samples including river, well and tap waters. The accuracy was evaluated by means of a recovery study, the results being in the range of 87–120%.

Determination of Phenol in Water by 4-Aminoantipyrine Spectrometry Using Peroxodisulfate as Oxidant

We studied using an ammonium peroxodisulfate as the oxidizing reagent instead of potassium hexacyanoferrate(III) on the 4-aminoantipyrine spectrometry for the determination of phenol. Suitable color development was obtained by the addition of 1 - 5 mL of ammonium peroxodisulfate solution (pH 10, 220 mmol/L) and 2 mL of 4-aminoantipyrine solution (98 mmol/L) to a 100 mL sample solution at pH 10 buffered with an ammonium chloride - ammonia solution (9.8 mol/L). The proposed procedure was applied to methyl benzoate extraction for determining small amounts of phenol in water. Results obtained by the proposed method were in agreement with that by the JIS method.

Development of a solid-phase extraction method followed by HPLC-UV detection for the determination of phenols in water.

A gradient HPLC-UV method for the determination of phenol and 10 of its derivatives was developed. Optimization studies were performed on parameters such as pH, solvents ratio, column temperature, sample volume, run time and flow rate. Calibration experiments were tested for linearity and reproducibility. Milli-Q water (HPLC water) was spiked with phenols’ standard solutions for recovery studies using solid-phase extraction (SPE) for analytes enrichment. The total run time was 20 min; the coefficient of determination, R 2 was > 0.99 for all analytes; mean percentage recovery ranged between 67.9±7.28 and 99.6±4.26. Detection limits ranged from 0.51 to 13.79 µg/ml while reproducibility expressed by the coefficient of variation of triplicate extractions was less than 12% for the 11 analytes. Two of the analytes, 2-chlorophenol and 2, 4-dichlorophenol were detected in some drinking water samples analysed.

Development and application of microporous hollow fiber protected liquid-phase microextraction via gaseous diffusion to the determination of phenols in water

A new organic solvent-free microextraction technique termed liquid–gas–liquid microextraction (LGLME) was developed. In this technique, a small amount (6 μl) of aqueous acceptor solution (0.5 M NaOH) is introduced into the channel of a 2.65 cm polypropylene hollow fiber. The hollow fiber is then immersed in an aqueous sample donor solution. The aqueous acceptor phase in the channel of the hollow fiber is separated from the sample solution by the hydrophobic microporous hollow fiber wall with air inside its pores. The analytes (phenols) passed through the microporous hollow fiber membrane by gas diffusion and were then trapped by the basic acceptor solution. After extraction, the acceptor solution was withdrawn into a microsyringe and injected into a capillary electrophoresis sample vial for subsequent analysis. Limits of detection of between 0.5 and 10 μg/l for eight phenols could be achieved. The relative standard deviations ( n = 6) of this technique between 2.7 and 7.6%. The technique also provides good enrichment factors for all the eight analytes.

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.

LC Determination of Mono-Substituted Phenols in Water Using Liquid–Liquid–Liquid Phase Microextraction

A simple liquid–liquid–liquid microextraction device of new design was used to pre-concentrate phenols from water samples before liquid chromatographic (LC) analysis. Extraction was induced by the pH difference inside and outside an organic phase located at the interface. The pH of the donor phase outside the organic phase was adjusted to 1 with HCl whereas the acceptor phase was a basic solution at pH 13. On stirring neutral phenols were extracted into the organic solvent then back-extracted into 1 μL of basic acceptor solution suspended from the tip of a micro syringe. The acceptor phase was then withdrawn into the micro syringe and injected directly into the LC. The technique uses a low-cost disposable extraction ‘device’ and is very convenient to operate. Up to 230-fold enrichment of analytes could be achieved. This procedure could also serve as a sample clean-up step because neutral and basic compounds were not extracted into the acceptor phase. The RSD (n = 5) was better than 6.2% and the linear calibration range was from 1 to 1000 µg–L−1 with r 2 ≥ 0.992.

Evaluation of a new reagent: anthraquinone-2-sulfonyl chloride for the determination of phenol in water by liquid chromatography using precolumn phase-transfer catalyzed derivatization.

A new reagent, anthraquinone-2-sulfonyl chloride, is used for the derivatizaton of phenols. Several compounds with different polarities are selected to evaluate the new reagent and derivatives of these phenols that are prepared via a facile pathway. The optimal conditions for analytical derivatization and mechanism of the derivatization reaction are discussed. The derivatization procedure involves an ion-pair extraction of the deprotonated phenols with a tetrabutylammonium counter ion in the organic phase. At the interface of two phases, the derivatization reaction occurs quantitatively at room temperature within 3 min. The derivatives are stable and readily amenable to analysis by normal-phase (NP) and reversed-phase (RP) high-performance liquid chromatography (HPLC). Excellent linearity response was demonstrated over the concentration range of 0.2-200 micromol/L at 320 nm for NP-HPLC and at 256 nm for RP-HPLC. Combined with preconcentration using a Waters Sep-Pak Plus C(18) cartridge, detection limits of phenols for water-sample analysis are as low as 1 x 10(-9) mol/L (approximately 0.1 microg/mL).

M-Aminophenylarsonic Acid as a Reagent for the Extraction Preconcentration of Phenol

The azocoupling reaction of phenol with the diazonium salt of m-aminophenylarsonic acid was used for the determination of phenol in water at a level of maximum permissible concentrations. The resulting compound is stable in a wide pH range, which made it possible to develop a procedure for the determination of phenol with the preconcentration of the azo compound by extraction to isobutanol at pH 2 and subsequent back extraction to the aqueous phase at pH ≥ 10. The high concentration coefficient of phenol (65) provides for determination of phenol down to 0.9 μg/L.