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.

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.

Chemiluminescence determination of chromium(VI), molybdenum(VI), and vanadium(V) with bis-(2,4,6-trichlorophenyl) oxalate and perylene

1982 ◽  
Vol 47 (6) ◽  
pp. 1606-1612 ◽  
Author(s):  
Záviš Holzbecher ◽  
Lubomír Kábrt ◽  
Lubomír Janšta
Keyword(s):  
Hydrogen Peroxide ◽  
Standard Deviation ◽  
Oxygen Transfer ◽  
Methyl Acetate ◽  
Catalytic Effect ◽  
Metal Salts ◽  
Experimental Conditions ◽  
Chromium Vi ◽  
Relative Standard

The effect of the experimental conditions (pH, ionic strength, hydrogen peroxide concentration) and of various metal salts on the chemiluminescence occurring during oxidation of bis-(2,4,6-trichlorophenyl) oxalate (TCPO) with hydrogen peroxide in the presence of perylene was studied in water-methyl acetate solutions. The spectrum of the emitted radiation was found practically identical with the fluorescence spectrum of perylene. The observed catalytic effect of Cr(IV), Mo(VI), and V(V) on the chemiluminescence reaction in question can be explained so that these elements form peroxo acids with hydrogen peroxide, thereby facilitating the oxygen transfer from the latter to TCPO. Based on this phenomenon, a method is suggested for the determination of the above elements in concentrations about 10-3 to 10-4 mol l-1; its precision, represented by the relative standard deviation, is about 3-4%, the limits of determination of Cr(VI), Mo(VI), and V(V) are approximately 5-10 μg.

Spctrophotometric Determination of Trace Ruthenium by its Catalytic Effect on Oxidation of 3,5-DiBr-PADAP with KIO4

2012 ◽  
Vol 554-556 ◽  
pp. 1999-2005
Author(s):  
Zhi Rong Zhou ◽  
Qun Wang ◽  
Shu Yuan Zhang
Keyword(s):  
Activation Energy ◽  
Standard Deviation ◽  
Detection Limit ◽  
Catalytic Reaction ◽  
Oxidation Reaction ◽  
Catalytic Effect ◽  
Optimum Conditions ◽  
Potassium Periodate ◽  
Relative Standard

A spectrophotometric method for the determination of ruthenium (III) is described, based on its catalytic effect on the oxidation reaction of 2-[(3,5-dibromo-2-pyridy)azo]-5-diethylaminophenol (3,5-diBr-PADAP) with potassium periodate in 0.008 mol/L sodium hydroxide medium and in the presence of OP emulsifier (p-iso-octyl phenoxy polyethoxy ethanol) at 100 °C. The above reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 530 nm for the catalytic reaction of 3,5-diBr-PADAP. The calibration curve for the recommended method was linear in the concentration range over 0.04 µg/L–1.0 µg/L and the detection limit of the method for Ru (III) is 0.012 µg/L. The influence of the factors such as acidity, concentration of reactants, reaction time, temperature and co-existing ions on the reaction is discussed. The optimum conditions of reaction are established and some kinetic parameters are determined. The apparent activation energy of catalytic reaction is 100.48 kJ/mol. The relative standard deviation for the determination of ruthenium (III) at the concentration of 0.02 µg/25mL is calculated to be 2.30 % (n=11). In combination with distilled separation, the method has been successfully applied for the determination of trace ruthenium (III) in some ores and metallurgy products with the relative standard deviations (RSD) over 1.8 %–2.9 % and the recovery over 98.1 %–103.1 %.

scholarly journals Two Spectrophotometric Assays for Dopamine Derivatives in Pharmaceutical Products and in Biological Samples of Schizophrenic Patients Using Copper Tetramine Complex and Tri-iodide Reagent

2005 ◽  
Vol 2005 (1) ◽  
pp. 1-9 ◽  
Author(s):  
F. A. Nour El-Dien ◽  
M. A. Zayed ◽  
Gehad. G. Mohamed ◽  
Reham G. El-Nahas
Keyword(s):  
Standard Deviation ◽  
Degradation Products ◽  
Outer Sphere ◽  
Pharmaceutical Products ◽  
Official Method ◽  
Good Precision ◽  
Experimental Conditions ◽  
Relative Standard ◽  
Schizophrenic Patients

Two simple, rapid, and sensitive spectrophotometric methods are proposed for the determination of levodopa (LD). The first method is based on coupling of 4-aminoantipyrine (4-AAP) with one of the dopamine derivatives (LD, CD) to give a new ligand that reacts with copper tetramine complex to give intensely colored chelates. The colored products are quantified spectrophotometrically at 525 and 520 nm for LD and CD, respectively. The optimization of the experimental conditions is described. The method has been used for the determination of19.7–69.0and18.1–54.3μg mL−1of LD and CD, respectively. The accuracy of the method is achieved by the values of recovery (100±0.2%) and the precision is supported by the low standard deviation (SD=0.17–0.59) and relative standard deviation (CV=0.4%–1.54%) values. The second method is based on the formation of ion-pair iodinated inner sphere or outer sphere colored complexes between the LD and triiodide ions at pH 5 and room temperature (23±3°C). This method has been used for the determination of LD within the concentration range39.44–78.88μg mL−1with SD=0.22–0.24and recovery percent=100±0.3%. The sensitivity of the two methods is indicated by Sandell's sensitivity of0.014–0.019g cm−2. The results of the two methods are compared with those of the official method. The interference of common drug additives, degradation products, and excipients was also studied. The proposed methods were applied successfully to the determination of the LD-CD synthetic mixture and Levocare drug. The determination of LD in urine of some schizophrenic patients was applied with good precision and accuracy. The reliability of the methods was established by parallel determinations against the official British pharmacopoeia method.

scholarly journals Kinetic determination of Se(IV) in pharmaceutical samples

2000 ◽  
Vol 65 (8) ◽  
pp. 595-601
Author(s):  
S.S. Mitic ◽  
J.I. Vucetic ◽  
S.M. Miletic ◽  
D.A. Kostic
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Reaction Rate ◽  
Kinetic Method ◽  
Kinetic Equations ◽  
Kinetic Determination ◽  
Pharmaceutical Samples ◽  
Inhibiting Effect ◽  
Concentration Interval

A kinetic method is described for the determination of Se(IV) based on its inhibiting effect on the Fe(III) catalysis of the oxidation of C6H5COONa with hydrogen peroxide. The detection limit is 0.06 pg cmT The relative error ranges between 2.1 and 9.5 % for the concentration interval 0.26 to 2.6 ?g cm-3. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined in order to assess the selectivity of the method. The method was applied for the determination of Se(IV) in pharmaceutical samples.

Determination of Prednisone Acetate at Trace Level by Flow Injection Analysis with Tris(1,10-Phenanthroline) Ruthenium(II) Chemiluminescence Detection

2011 ◽  
Vol 236-238 ◽  
pp. 2729-2732
Author(s):  
Pi Xue Gong ◽  
Wei Hua Liu ◽  
Wen Wen Liu ◽  
Kang Du ◽  
Kang Liu ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Flow Injection ◽  
Acidic Medium ◽  
Luminescent Properties ◽  
Chemiluminescence Detection ◽  
Trace Level ◽  
Experimental Conditions ◽  
Relative Standard

A simple, sensitive and rapid method for flow injection with chemiluminescence analysis has been developed for the determination of prednisone acetate at trace level. This method is based on the luminescent properties of the tris(1,10-phenanthroline) ruthenium(II)-potassium permanganate -prednisone acetate in acidic medium sensitized by Na2SO3. The optimized experimental conditions are evaluated. Under the optimum experimental conditions, the linear ranges of prednisone acetate are: 4.0×10-10~4.0×10-8g·mL-1and 4.0×10-8~2.0×10-7g·mL-1with a low detection limit is 4.5×10-11g·mL-1and the relative standard deviation for 1.0×10-8g·mL-1sample is 1.04% (n=11). The proposed method has been successfully applied to the determination of prednisone acetate in tablets.

A novel kinetic-spectrophotometric method for determination of nitrites in water

2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Zenovia Moldovan
Keyword(s):  
Kinetic Method ◽  
Calibration Graph ◽  
Linear Calibration ◽  
Nitrite Concentration ◽  
Experimental Conditions ◽  
Sulfuric Acid Medium ◽  
Relative Standard ◽  
Kinetic Spectrophotometric ◽  
Drinking Water Samples

AbstractA simple, selective and sensitive kinetic method for the determination of nitrite in water was developed. The method is based on the catalytic effect of nitrite on the oxidation of methylene blue (MB) with bromate in a sulfuric acid medium. During the oxidation process, absorbance of the reaction mixture decreases with the increasing time, inversely proportional to the nitrite concentration. The reaction rate was monitored spectrophotometrically at λ = 666 nm within 30 s of mixing. Linear calibration graph was obtained in the range of 0.005–0.5 μg mL−1 with a relative standard deviation of 2.09 % for six measurements at 0.5 μg mL−1. The detection limit was found to be 0.0015 μg mL−1. The effect of different factors such as acidity, time, bromate concentration, MB concentration, ionic strength, and order of reactants additions is reported. Interference of the most common foreign ions was also investigated. The optimum experimental conditions were: 0.38 mol L−1 H2SO4, 5 × 10.4 mol L−1 KBrO3, 1.25 × 10.5 mol L−1 MB, 0.3 mol L−1 sodium nitrate, and 25°C. The proposed method was conveniently applied for the determination of nitrite in spiked drinking water samples.

scholarly journals Online Preconcentration and Determination of Trace Amounts of Zinc in Nature Waters

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Liang Wei ◽  
Xinshen Zhang ◽  
Yichun Dai ◽  
Jin Huang ◽  
Yong-hong Xie ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Tween 80 ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Buffer Solutions ◽  
Relative Standard ◽  
On Line ◽  
Standard Solution ◽  
Zinc Determination

A simple, sensitive, reliable and flexible flow injection spectrophotometric method is proposed for on-line preconcentration and determination of trace amounts of zinc in water. At the presence of Tween-80 in pH 9.3 buffer solutions, the shade of color of Zn (II)-PAN complex is in a linear relation to the zinc amount at the point of the maximum absorption peak of 560 nm. The optimal experimental conditions, including reaction conditions and preconcentration conditions, had been obtained. The linear range of the proposed method was between 2.0 and 360 μg L−1and the detection limit was 0.42 μg L−1. The relative standard deviation was 3.55% and 2.14% for 5.0 μg L−1and 50 μg L−1of zinc standard solution (n=8). The method had been successfully applied to zinc determination in water samples and the analytical results were satisfactory.

scholarly journals Catalytic Spectrophotometric Method for Determination of Formaldehyde Based on its Catalytic Effect on the ReactionBetween Bromate and Safranin

2010 ◽  
Vol 7 (s1) ◽  
pp. S481-S487
Author(s):  
Mohsen Keyvanfard
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Catalytic Effect ◽  
Limit Of Detection ◽  
Kinetic Method ◽  
Fixed Time ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Replicate Measurements

The reaction monitored spectrophotometrically by measuring the decrease in absorbance of the reaction mixture at 533 nm. The fixed-time method was used for the first 60s. For initiation of the reaction, under the optimum conditions, in the concentration range of 0.02-1.5 μg mL–1formaldehyde can be determined with a limit of detection 9.5 ng mL–1. The relative standard deviation of five replicate measurements is 2.3% for 0.5 μg mL–1of formaldehyde. The method was used for the determination of formaldehyde in water samples with satisfactory results. A new simple and fast catalytic kinetic method for the determination of trace amount of formaldehyde is described. The method is based on the catalytic effect of formaldehyde on the oxidation of safranin by bromate in the present of sulfuric acid.

scholarly journals Determination of Amineptine and Amprolium Hydrochlorides through Ion Associates with Cobalt (II) Thiocyanate

2002 ◽  
Vol 70 (4) ◽  
pp. 379-390 ◽  
Author(s):  
Abou Attia Fekria M.
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Organic Phase ◽  
Ion Pairs ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
New Methods ◽  
Quantitative Extraction ◽  
Relative Standard

Two new methods for the determination of amineptine (AMN) and amprolium (AMP) have been developed. The methods consist of extractin the ion - pairs between the drug and the inorganic complex [Co (SCN)4]−2. The optimal experimental conditions of both methods including pH, concentration of Co (II) and tlxocyanate ions, and the organic solvents were studied. The optimum pH was found to be 3.9, nitrobenzene proved to be the most suitable solvent, giving quantitative extraction for the two drugs. The two drugs can be determined in the organic phase spectrophotometrically at 625 nm showing Sandell sensitivities of 0.19 and 0.12 µg cm−2 with relative standard deviation of 0.46 and 0.87 % for amineptine and amprolium, respectively.The indirect method was also applied to measure cobalt in the organic phase by atomic absorption spectrometry at 240.7 nm, and the relative standard deviation of the method is approximately 0.35 and 0.29 % for amineptine and amprolium, respectively. The proposed methods were found to be suitable for the accurate, simple and rapid analysis of amineptine and amprolium hydrochlorides in the bulk drugs and in pharmaceutical forms.

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