scholarly journals STUDY OF THE EFFECT OF ETHANOL ADDITION AND SOLUTION HEATING ON THE DETERMINATION OF AMMONIA IN WATER BY INDOPHENOL BLUE METHOD

2010 ◽  
Vol 2 (2) ◽  
pp. 97-101 ◽  
Author(s):  
Hasri Hasri ◽  
Mudasir Mudasir
Keyword(s):  
River Water ◽  
Aqueous Media ◽  
Analytical Performance ◽  
Water Medium ◽  
Blue Color ◽  
Ammonia Determination ◽  
Relative Standard ◽  
Ethanol Addition ◽  
Optimal Heating

The effect of ethanol addition and solution heating on the analytical performance of the determination of ammonia in water by indophenol blue method was studied. The addition of ethanol and solution heating was intended to overcome the problem of reproducibility and sensitivity ussually found in the determination of ammonia by indophenol blue method which is carried out in 100 % aqueous media. The determination of ammonia was done indirectly by reacting ammonia in the sample with hypochloride and phenol using nitroprussida as catalyst to yield blue color-intense chromophore of indophenol. The chromophore was then detected by UV-Visible spectrophotometer. The proposed method was applied for the determination of ammonia in various samples of river water located in Yogyakarta and Makassar.             Results of the study showed that ethanol addition into analytical solution and solution heating enhanced the formation of indophenol blue. The optimal heating was achieved after 90 minutes of mixing. In ethanol/water medium (50/50, v/v), indophenol blue exhibited maximum absorbance at 648 nm. The analytical performance of ammonia determination by indophenol blue method in this medium is as followed: detection limit = 0.03 ppm, relative standard deviation (RSD) = 2.50 % and the calibration curve was linear in the concentration range of 0.0 - 0.4 ppm with correlation coefficient (r) = 0.9968. Results of ammonia determination in various samples of river water showed that the highest concentration of ammonia (2.421 ppm) was found in Tallo river, Makassar, while the lowest (0.359 ppm) was shown by the river near SGM factory, Yogyakarta.   Keywords: Ammonia, Ethanol, Spectrophotometry, Indophenol blue.

scholarly journals A kinetic method for the determination of phenol

2002 ◽  
Vol 67 (10) ◽  
pp. 661-667 ◽  
Author(s):  
Snezana Mitic ◽  
Valentina Zivanovic
Keyword(s):  
Standard Deviation ◽  
River Water ◽  
Reaction Rate ◽  
Kinetic Method ◽  
Potassium Periodate ◽  
Experimental Conditions ◽  
Inhibiting Effect ◽  
Relative Standard ◽  
Kinetic Expression

Akinetic method for the determination of phenol is proposed. The method is based on the inhibiting effect of phenol on the Mn(II) catalysis of the oxidation of malachite green with potassium periodate. The reaction rate was followed spectrophotometrically at 615 nm. Kinetic expression for the reaction in the presence and absence of phenol are postulated. The optimal experimental conditions for the determination of phenol were established and phenol was determined in concentrations from 30.0 to 188.0 ng/cm3 with a relative standard deviation of 5.5%. The lower detecton limit is 7.8 ng/cm3. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The method was applied for the determination of phenol in tap and river water.

Atomic Absorption Spectrometric Determination of Arsenite in Water Samples by Graphite Furnace After Extraction with Ammonium sec-Butyldithiophosphate

1984 ◽  
Vol 67 (2) ◽  
pp. 277-280
Author(s):  
Dipankar Chakraborti ◽  
Kurt J Irgolic ◽  
F Adams
Keyword(s):  
Atomic Absorption ◽  
River Water ◽  
Water Samples ◽  
Graphite Furnace ◽  
Dimethylarsinic Acid ◽  
Relative Standard ◽  
Methylarsonic Acid ◽  
Atomic Absorption Spectrometric ◽  
Hexane Solution

Abstract Arsenite—but not arsenate, methylarsonic acid, or dimethylarsinic acid—is extracted from water samples by 5 mL of a 0.01M hexane solution of rec-dibutylthiophosphate. A 10 μL aliquot of the extract is injected into an atomic absorption spectrometer with a graphic furnace for the determination of arsenic. The calibration curve is linear to 1500 Dg As. Quantities of arsenic as low as 100 ng As (0.2 ppb As when contained in 500 mL) can be confidently determined. The method was tested with natural river water and synthetic river water. The relative standard deviations associated with the recoveries of arsenite from natural water and synthetic river water spiked with arsenite range from 4.8 to 8.0%. Ten to 15 arsenite determinations can be completed in 1h.

scholarly journals Determination of Semivolatile Organic Compounds in Environmental Samples by Gas Chromatography/Mass Spectrometry after Extraction by Cyclic Steam Distillation

2003 ◽  
Vol 86 (2) ◽  
pp. 246-256
Author(s):  
Kuniaki Kawata ◽  
Akiko Tanabe ◽  
Hiroaki Yagoh ◽  
Tsuyoshi Ibaraki ◽  
Akio Yasuhara ◽  
...  
Keyword(s):  
Essential Oil ◽  
River Water ◽  
Organic Compounds ◽  
Aromatic Hydrocarbons ◽  
Gas Chromatography Mass Spectrometry ◽  
Semivolatile Organic Compounds ◽  
Relative Standard ◽  
Water And Soil Samples ◽  
Polycyclic Aromatic

Abstract A method was developed for the multiple determination of semivolatile organic compounds found in groundwater, river water, seawater, sediment, and soil. Forty standard compounds were determined: n-alkenes, cycloalkanes, aromatic hydrocarbons, and polycyclic aromatic hydrocarbons. The compounds were isolated from water and soil samples by using an essential oil distillator (cyclic steam distillator) with hexane as a solvent. The extract was cleaned by using a silica gel cartridge with an acetone–hexane solution. The compounds were determined by using a gas chromatograph/mass spectrometer with 12 stable isotope-labeled compounds (surrogate compounds). The efficiencies of recoveries from water samples were 80.0–106% for groundwater, 80.1–106% for river water, and 81.2–103% for seawater. The relative standard deviation (RSD) values were 2.05–16.0% for groundwater, 3.22–16.6% for river water, and 4.45–16.0% for seawater. The efficiencies of recoveries from sediment and soil were 71.5–96.4% and 70.1–99.8%, respectively. RSD values ranged from 2.27 to 16.0% for sediment and from 2.12 to 15.1% for soil. Adjustment of recovery efficiencies of standard compounds by using surrogate compounds gave more accurate values. The present study proved that an essential oil distillator provides satisfactory results for multiple determinations of the semivolatile compounds in environmental waters, sediment, and soil.

scholarly journals Electrochemical and analytical performance of boron-doped diamond electrode for determination of ascorbic acid

2017 ◽  
Vol 10 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Ivana Sálusová ◽  
Kristína Cinková ◽  
Barbora Brtková ◽  
Marian Vojs ◽  
Marián Marton ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Analytical Performance ◽  
Current Response ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Relative Standard ◽  
Pulse Voltammetry

Abstract The electrochemical behavior and determination of ascorbic acid (AA) was investigated at a bare boron-doped diamond (BDD) electrode using cyclic and differential pulse voltammetry. The influence of pH of supporting electrolyte and scan rate on the current response of analyte was examined to select the suitable experimental conditions. It was found that AA provided one well-shaped irreversible and diffusioncontrolled oxidation peak at +0.87 V vs. Ag/AgCl in Britton-Robinson buffer pH 4.0. Applying differential pulse voltammetry, the peak current of AA was linearly proportional to its concentration from 5 × 10-6 to 2 × 10-4 mol L-1 (R2 = 0.999), with the limit of detection of 1.1 × 10-6 mol L-1 and the good repeatability (relative standard deviation of 2.3 %). The developed electroanalytical protocol was successfully applied to determine the content of AA in commercial pharmaceutical preparations, based on the standard additions method, with the obtained recovery of 122 %. The accomplished analytical performance indicates that BDD electrodes are promising electrochemical sensors for pharmaceutical analysis.

scholarly journals Investigation of Charge Transfer Complex Formation Between Fe(III) and 2,6-Dihydroxy Benzoic Acid and its Applications for Spectrophotometric Determination of Iron in Aqueous Media

2009 ◽  
Vol 6 (4) ◽  
pp. 985-992 ◽  
Author(s):  
Mohammad Saeid Hosseini ◽  
Sara Madarshahian
Keyword(s):  
Charge Transfer ◽  
Stability Constant ◽  
Benzoic Acid ◽  
Spectrophotometric Determination ◽  
Dynamic Range ◽  
Charge Transfer Complex ◽  
Aqueous Media ◽  
Acidic Media ◽  
Relative Standard

On the basis of affinity of Fe(III) ions toward functional groups of 2,6-dihydroxy benzoic acid (2,6-DHB), a charge transfer complex (CT) is formed between Fe(III) ion and 2,6-DHB in acidic media. The stoichiometry and stability constant of the complex was determined using both mole ratio and Job’s methods. The stability constant of 1:1 complex formed in acidic media is 2.55±0.14×105(mole ratio) or 2.70±0.12×105(Job), in which the quantities are in agreement with together. This method was used for spectrophotometric determination of Fe(III) in aqueous media. The dynamic range and detection limit (DL) were 1.2×10-5to 3.6×10-4M and 1.5×10-6M, respectively. The relative standard deviation (RSD) was found to be 0.76% in the replicate treatments (n=7) with 1.6×10-4M Fe(III). The practical applicability of the method was confirmed using a synthetic certificated reference material (CRM) and spiked natural water samples.

Kinetic Method for the Determination of 2,4-Dinitrophenol

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
S. S. Mitic ◽  
V. V. Zivanovic ◽  
G. Z. Miletic ◽  
D. A. Kostic ◽  
I. D. Rasic
Keyword(s):  
Detection Limit ◽  
River Water ◽  
Standard Error ◽  
Kinetic Method ◽  
Relative Standard Error ◽  
Potassium Periodate ◽  
Experimental Conditions ◽  
Inhibiting Effect ◽  
Relative Standard

A kinetic method for the determination of dinitrophenol is proposed. The method is based on the inhibiting effect of 2,4-dinitrophenol on the Mn(II) catalysis of the oxidation of malachite green with potassium periodate. The reaction was monitored spectrophotometrically at 615 nm. Kinetic expressions for the reaction are postulated. The optimal experimental conditions for the determination of 2,4-dinitrophenol were established and 2,4-dinitrophenol was determined in concentrations from 0.092-0.92 mg . mL-1 with relative standard error of 5.9 %. Detection limit is 0.014 mg . mL-1. The selectivity of the method is appropriate. The method was applied for the determination of dinitrophenol in urine and river water.

scholarly journals Amine-functionalized magnetic activated carbon as an adsorbent for preconcentration and determination of acidic drugs in environmental water samples using HPLC-DAD

2020 ◽  
Vol 18 (1) ◽  
pp. 1218-1229 ◽  
Author(s):  
Mpingana Ndilimeke Akawa ◽  
Kgogobi Mogolodi Dimpe ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Activated Carbon ◽  
River Water ◽  
Water Samples ◽  
High Performance ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Array Detector ◽  
Acidic Drugs ◽  
Relative Standard

AbstractIn the present study, a convenient and highly effective method was developed for the quantification of acidic drugs in wastewater and river water samples. Ultrasonic-assisted magnetic solid phase extraction employing magnetic waste tyre-based activated carbon nanocomposite functionalized with [3-(2-aminoethylamino)propyl]trimethoxysilane as a cost-effective and efficient adsorbent was used for the extraction and preconcentration of acidic drugs (naproxen [NAP], ketoprofen (KET) and diclofenac [DIC]). The quantification of target analytes was achieved by high‐performance liquid chromatography with diode array detector. Under optimum conditions, the detection limit, quantification limit and relative standard deviation obtained for the analytes of interest ranged from 0.38 to 0.76, 1.26 to 2.54 µg L−1 and 2.02 to 4.06%, respectively. The applicability of the developed method was assessed by the spike recovery tests and the relative recoveries proved that the method is reliable for the determination of acidic drugs in wastewater. Thereafter, the method was applied successfully for the determination of NAP, KET and DIC in river water, influent and effluent wastewater.

scholarly journals Rapid Method for the Determination of 5-Hydroxymethylfurfural and Levulinic Acid Using a Double-Wavelength UV Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Junhua Zhang ◽  
Junke Li ◽  
Yanjun Tang ◽  
Guoxin Xue
Keyword(s):  
Standard Deviation ◽  
Rapid Method ◽  
Present Method ◽  
Levulinic Acid ◽  
Uv Spectroscopy ◽  
Spectral Interference ◽  
Water Medium ◽  
Limit Of Quantification ◽  
Relative Standard

This study reports on a rapid method for the determination of levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) in acid hydrolyze system of glucose based on UV spectroscopy. It was found that HMF and LA have a maximum absorption at the wavelengths of 284 nm and 266 nm, respectively, in a water medium, and the absorptions of HMF and LA at 284 nm and 266 nm follow Beer’s law very well. However, it was found that a major spectral interference species will arise in the quantification of HMF and LA; nonetheless, this interference can be eliminated through the absorption treatment of charcoal. Therefore, both HMF and LA can be quantified with a double-wavelength technique. The repeatability of the method had a relative standard deviation of less than 4.47% for HMF and 2.25% for LA; the limit of quantification (LOQ) was 0.017 mmol/L for HMF and 4.68 mmol/L for LA, and the recovery ranged from 88% to 116% for HMF and from 94% to 105% for LA. The present method is simple, rapid, and accurate. It is suitable to use in the research of the preparation of HMF and LA in biorefinery area.

scholarly journals Determination of Glyphosate Residues in Plants by Precolumn Derivatization and Coupled-Column Liquid Chromatography with Fluorescence Detection

2000 ◽  
Vol 83 (3) ◽  
pp. 728-734 ◽  
Author(s):  
Félix Hernández ◽  
Carmen Hidalgo ◽  
Juan V Sancho
Keyword(s):  
Column Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Media ◽  
Precolumn Derivatization ◽  
Trace Level ◽  
Plant Materials ◽  
Tomato Plants ◽  
Relative Standard ◽  
Pear Trees

Abstract A rapid method was developed for the trace-level determination of glyphosate in olives. After extraction of the glyphosate with water–dichloromethane and simultaneous removal of the olive oil, an aliquot of the aqueous extract is derivatized with 9-fluoroenylmethyl chloroformate (9-fluorenylmethoxycarbonyl chloride; FMOC-Cl) to produce a highly fluorescent derivative. A 2 mL aliquot of this extract is injected directly into a coupled-column liquid chromatography system with fluorimetric detection (LC/LC–FD). The procedure was validated by recovery experiments at 3 spiking levels; recoveries ranged from 80 to 97% with relative standard deviations of 3–6%. The limits of detection and quantitation were estimated to be 0.01 and 0.05 mg/kg, respectively. The method was also applied to other plant materials, i.e., tomato plants, strawberry plants, and pear trees (branches, leaves, and fruits) suspected to be contaminated by glyphosate. In all these cases, the extraction was performed in aqueous media. The derivatization reaction was modified by increasing the FMOC-Cl concentration, to ensure a quantitative reaction between analyte and reagent in the presence of high levels of coextractives, which also react with FMOC-Cl. The final determination was by LC/LC–FD, yielding a rapid, selective, and sensitive method for the determination of glyphosate residues in these samples. The method was tested with real-world samples after application of glyphosate to the surrounding area of crops.

scholarly journals Factors Affecting Multiresidue Determination of Priority Herbicides when Using Solid-Phase Microextraction

2002 ◽  
Vol 85 (2) ◽  
pp. 486-493 ◽  
Author(s):  
Dimitra A Lambropoulou ◽  
Ioannis K Konstantinou ◽  
Triantafyllos A Albanis
Keyword(s):  
River Water ◽  
Water Samples ◽  
Natural Waters ◽  
Sea Water ◽  
Solid Phase ◽  
Time Profile ◽  
Factors Affecting ◽  
Stirring Rate ◽  
Relative Standard

Abstract A solid-phase microextracton (SPME) procedure was developed for the determination of 10 selected organonitrogen herbicides (s-ethyl dibropylthiocarbamate [EPTC], molinate, propachlor, trifluralin, simazine, atrazine, propazine, terbuthylazine, alachlor, and prometryn) and was tested with various natural waters. Gas chromatography coupled with flame thermionic and mass spectrometric detection was used for quantitation. For this purpose, polydimethylsiloxane and polyacrylate fibers were used and the factors affecting the SPME process such as pH, ionic strength, methanol content, memory effect, stirring rate, and adsorption-time profile were investigated and optimized. By using spiked liquid chromatography water, optimal factors were determined to be 25% salt, <0.5% methanol, stirring rate of 960 rpm, pH 4, and an equilibrium time of 30 min. These conditions were used in further studies of the fibers and in analysis of natural water samples. The method was applied to spiked natural waters such as ground water, sea water, lake water, and river water at a concentration range of 0.5–10 μg/L. Limits of detection ranged from 5 to 90 ng/L, and precision ranged from 5 to 15% (as relative standard deviation), depending on the pesticide, fiber, and detector used. The recoveries of herbicides were 70.2–118.4%, and the average r2 values of the calibration curves were >0.99 for all analytes. The results demonstrate the suitability of the SPME method to determine these organonitrogen herbicides in various natural waters. River water samples originating from the Epirus region (Northwestern Greece) were analyzed to verify the performance of the optimized method by comparing the results obtained by SPME with those obtained by using conventional solid-phase extraction of the selected herbicides.

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