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 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.

Determination of p-Toluenesulfonamide in Ice Cream by Combination of Continuous Flow and Liquid Chromatography: Summary of Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 672-674 ◽  
Author(s):  
Paul R Beuaars ◽  
Remmelt Van Dijk ◽  
Arie Brands
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Ice Cream ◽  
Relative Standard ◽  
On Line ◽  
Positive Results

Abstract A collaborative study of the determination of p-tolu-enesulfonamide (p-TSA) in ice cream by a combination of continuous flow and on-line liquid chromatography was conducted. Seven ice cream samples containing 0-6.35 mg p-TSA/kg at 4 levels (1 blank and 3 pairs of split level samples) were analyzed by 11 laboratories. For all samples analyzed, the repeatability relative standard deviation varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviation ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55,1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101 %). No false positive results were reported for the blank sample, and no interference was encountered by the presence of vanillin in samples. The method has been adopted first action by AOAC INTERNATIONAL.

scholarly journals Online Determination of Trace Amounts of Tannic Acid in Colored Tannery Wastewaters by Automatic Reference Flow Injection Analysis

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Liang Wei
Keyword(s):  
Tannic Acid ◽  
Flow Injection ◽  
Flow Injection Analysis ◽  
Alkaline Solutions ◽  
Experimental Conditions ◽  
Reference Flow ◽  
Relative Standard ◽  
Standard Solution ◽  
Acid Reduction

A simple, rapid and sensitive method was proposed for online determination of tannic acid in colored tannery wastewater by automatic reference flow injection analysis. Based on the tannic acid reduction phosphotungstic acid to form blue compound in pH 12.38 alkaline solutions, the shade of blue compound is in a linear relation to the content of tannic acid at the point of the maximum absorption peak of 760 nm. The optimal experimental conditions had been obtained. The linear range of the proposed method was between 200 μgL−1to 80 mgL−1and the detection limit was 0.58 μgL−1. The relative standard deviation was 3.08% and 2.43% for 500 μgL−1and 40 mgL−1of tannic acid standard solution, respectively, (n=10). The method had been successfully applied to determination of tannic acid in colored tannery wastewaters and the analytical results were satisfactory.

Online Determination of Anionic Surfactant in Environmental Water

2012 ◽  
Vol 610-613 ◽  
pp. 1113-1116
Author(s):  
Liang Wei ◽  
Yi Chun Dai
Keyword(s):  
Anionic Surfactant ◽  
Sodium Dodecyl ◽  
Environmental Water ◽  
Buffer Solution ◽  
Experimental Conditions ◽  
Ethyl Violet ◽  
Relative Standard ◽  
Potassium Hydrogen ◽  
Standard Solution

It was found that ethyl violet can react with sodium dodecyl benzene sulfate (SDBS) to form ion associates in pH 2.2 ~ 2.8 of buffer solution of potassium hydrogen phthalate and hydrochloric acid in the presence of polyvinyl alcohol. Based on this, a method was proposed for online determination of anionic surfactant in environmental waterby. Under the optimum experimental conditions, Beers law was obeyed in the concentration range of 80 µg/L ~ 3500 µg/L of anionic surfactant (SDBS). The relative standard deviation of 2.1% was was obtained by injecting 800 µg/L of sodium dodecyl benzene sulfate standard solution (n=10). The detection limit calculated from three times of the average background noise was 4.39 µg/L. The proposed method had been applied successfully to the determination of anionic surfactant in environmental water and the results showed good agreement with that of the standard method.

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.

Online Monitoring of Trace Copper (II) in Environmental Waters

2012 ◽  
Vol 599 ◽  
pp. 188-191
Author(s):  
Liang Wei ◽  
Yi Chun Dai
Keyword(s):  
Online Monitoring ◽  
Atomic Absorption Spectrophotometry ◽  
Neutral Red ◽  
Environmental Waters ◽  
Experimental Conditions ◽  
Standard Curve ◽  
Relative Standard ◽  
Standard Solution ◽  
Catalytic Spectrophotometry

Based on the fact that copper can catalyze the fading reaction of neutral red reduced by hydrogen peroxide using the alanine as a sensitizer in NH4Cl-NH3•H2O medium (pH 8.0), a method was developed for online monitoring of trace copper in environmental waters by flow injection catalytic spectrophotometry. The experimental conditions were optimized. Under optimum conditions, the linear range of the proposed method was between 1.0 µg/L to 125 µg/L and the correlation coefficient of standard curve was 0.9995. The detection limit of the proposed method was 0.11 µg/L. The relative standard deviation of 2.7% and 1.5% was obtained by injecting 15.00 µg/L and 100.00 µg/L copper of standard solution respectively (n=8). The proposed method had been applied to determination of trace amounts of copper in environmental waters. The results were in good agreement with those obtained by atomic absorption spectrophotometry (AAS)

Gas-Liquid Chromatographic Determination of Fluchloralin in Formulations

1977 ◽  
Vol 60 (5) ◽  
pp. 1145-1147
Author(s):  
Gregory S Grimes
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed that is precise, rapid, simple, and specific for fluchloralin in emulsifiable liquid formulation. Sample and reference standard are weighed, internal standard solution is added, and an aliquot of the mixture is injected onto the chromatographic column. Fluchloralin gives a sharp symmetrical peak at about 5.4 min. The internal standard has a broader symmetrical peak at about 6.9 min. The relative standard deviation for 21 consecutive injections of the standard solution was 0.3773%. The method was compared with the official GLC method, 6.210–6.215, for the structurally similar trifluralin. Fluchloralin gave a sharp symmetrical peak at about 8.5 min; the internal standard had a sharp symmetrical peak at about 9.2 min. The relative standard deviation of 21 consecutive injections of reference standard solution was 0.6988%. Comparison of the variances of the 2 methods by the F-test at the 99% confidence level showed that the proposed method demonstrated substantially better precision.

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.

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.

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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