Voltammetric determination of Al(III) with adsorptive preconcentration of the pyrocatechol violet complex

1991 ◽  
Vol 69 (9) ◽  
pp. 1418-1426 ◽  
Author(s):  
Dragic V. Vukomanovic ◽  
John A. Page ◽  
Gary W. Vanloon
Keyword(s):  
Metal Species ◽  
Aqueous Samples ◽  
Linear Calibration ◽  
Pyrocatechol Violet ◽  
Key Words Aluminium ◽  
Standard Additions ◽  
The Difference ◽  
A Current ◽  
Good Agreement

A method is described for the determination of aluminium in aqueous samples by linear scan voltammetry after adsorptive accumulation of the pyrocatechol violet (PCV) complex. A pH 6.5 triethanolamine/perchloric acid electrolyte is used for the determination with adsorption onto a mercury drop electrode at −0.50 V (vs a Ag/AgCl/satd KCl reference). Scanning cathodically after adsorption gave a current peak at −0.70 V for reduction of adsorbed PCV and a peak at −0.90 V for reduction of the adsorbed Al-PCV complex. The peaks were well resolved. Using 1.0 μM PCV and a 60 s adsorption period gave linear calibration curves for Al in the range 1 to 25 ng mL−1 Al. The detection limit was 0.1 ng mL−1 Al. For analysis, calibration by the method of standard additions is required. Most other metal species do not interfere, but vanadium (V(IV) and V(V)) forms a complex with PCV that is adsorbed and reduced at the same potential as Al–PCV. The interference may be eliminated by complexation of the V with citrate. Al and V present together may be determined by analysis in the absence of citrate (total: Al + V) and in the presence of citrate (Al); V is determined as the difference in the two values.The analysis of a range of samples with Al concentrations from 6 ng mL−1 to 3 μg mL−1 gave results which were in good agreement with those obtained by other methods. Key words: aluminium, pyrocatechol violet, adsorption, voltammetry, environmental.

Rapid Determination of Sulfite by Flow Injection Analysis Based on Fuchsin′s Addition

2013 ◽  
Vol 295-298 ◽  
pp. 950-953 ◽  
Author(s):  
Dong Yuan ◽  
Da You Fu ◽  
Wen Yuan Tan
Keyword(s):  
Flow Injection ◽  
Addition Reaction ◽  
Rapid Determination ◽  
Sampling Rate ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Good Agreement

A rapid spectrophotometric method for flow injection determination of sulfite in tan wastewater is described. The proposed method was based on the addition reaction of sulfite with fuchsin in Na2B4O7-NaOH medium. The optimum conditions allow a linear calibration range of 0.01-1.20 μg ml-1 SO32-. The detection limit is 0.0023μg ml-1 (S/N=3), and the relative standard deviation for night replicate measurements is 1.1% for 0.5μg ml-1 of sulfite. The sampling rate is 60 samples h-1. The procedure has been applied to the determination of sulfite in tan wastewater. The results were in good agreement with those obtained by pararosaniline method.

The Automated Determination of Serum Uric Acid

1966 ◽  
Vol 12 (11) ◽  
pp. 748-766 ◽  
Author(s):  
Stanley Morgenstern ◽  
Richard V Flor ◽  
James H Kaufman ◽  
Bernard Klein
Keyword(s):  
Uric Acid ◽  
Serum Uric Acid ◽  
Enzymatic Reaction ◽  
Enzymatic Determination ◽  
Before And After ◽  
The Difference ◽  
Automated Determination ◽  
Colorimetric Reaction ◽  
Good Agreement

Abstract An automated procedure is presented for the enzymatic determination of serum uric acid on both the AutoAnalyzer and the Robot Chemist. The procedure measures as the neocuproine complex, the difference in the amount of Cu+ formed by reaction of a Cu++-alkanolamine buffered solution with serum uric acid under precisely controlled conditions before and after uricase treatment of the serum. The difference is proportional to the true serum uric acid content. The elements contributing to the enzymatic reaction, the colorimetric reaction, and the elimination of interferences were investigated. Comparison of serum uric acid values obtained by this method with those obtained by ultraviolet spectrophotometry show very good agreement.

Quantitative Determination by X-Ray Diffractometry of Calcium Sulfate and Calcium Carbonate in Airborne Dusts

1988 ◽  
Vol 3 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Toshihiro Nakamura
Keyword(s):  
Calcium Carbonate ◽  
Calcium Sulfate ◽  
Mutual Interference ◽  
Half Width ◽  
Linear Calibration ◽  
X Ray ◽  
Relative Standard ◽  
Diffraction Peaks ◽  
The Difference

AbstractA quantitative simultaneous determination method by X-ray powder diffractometry is described for calcium sulfate and calcium carbonate in airborne dusts. In order to eliminate the mutual interference among diffraction peaks, and to avoid the presence of the hydration isomers of calcium sulfate, dust samples were heated at 350°C for 2 h. To reduce the errors due to the difference-in crystallinity between the standard materials and the samples, the synthesized calcium sulfate anhydrate (anhydrite) was heated to such an extent that the half-width of the 002,020 peak was identical with that of the anhydrite in pretreated dust samples. Standard calcium carbonate (calcite) was ground until the half-width and the orientation index of the 104 peak of calcite was identical with that of the calcite in dust samples. Linear calibration curves were obtained throughout the range of 0 ∼ 30 wt% for anhydrite and the range of 0 ∼ 10 wt% for calcite, respectively. The determination limits were 0.2 wt% for anhydrite and 0.3 wt% for calcite. Relative standard deviations were 3.4 % for 8.0 wt% of anhydrite and 1.8% for 5.4 wt% of calcite. The present method is applicable to determination of calcium sulfate and calcium carbonate in actual dust samples.

scholarly journals Determination of trace amounts of selenium in natural spring waters and tea samples by catalytic kinetic spectrophotometry

2019 ◽  
Vol 44 (4) ◽  
pp. 57 ◽  
Author(s):  
Ramazan Gürkan ◽  
Nevalnur Zeynep Gürkan
Keyword(s):  
Acidic Medium ◽  
Kinetic Method ◽  
Speciation Analysis ◽  
Fixed Time ◽  
Kinetic Spectrophotometry ◽  
The Difference ◽  
Natural Spring ◽  
Good Agreement ◽  
Catalytic Kinetic Spectrophotometry

In this work, a new kinetic method is described for the determination of trace Se(IV) in natural spring waters and commercial tea samples. The method is based on the activation of Se(IV) onto the indicator reaction in acidic medium. The reaction was monitored using a fixed time approach of 20 min at 680 nm. The variables affecting the reaction rate were evaluated and optimized. The method allows the determination of Se(IV) in the range of 0.0125-1.0 mg L-1 with a detection limit of 3.6 µg L-1. The precision was in range of 0.63-3.15% (as RSD %) with a higher recovery than 98.6%. The method has been found to be selective against matrix effect. The method was applied to the speciation analysis of inorganic Se species present in the selected samples. The method was statistically validated by analysis of two certified samples and comparing the obtained results to those of HG-AAS analysis. Also, the total Se levels of the samples were determined by using both methods after conversion of Se(VI) into Se(IV) in ultrasonic bath in acidic medium for 30 min at 85-90 °C. The results were in good agreement with those of HG-AAS. The Se(VI) level of the samples was calculated from the difference between amounts of total Se and Se(IV).

Improved determination of aluminum in serum and urine with use of a stabilized temperature platform furnace.

1982 ◽  
Vol 28 (10) ◽  
pp. 2139-2143 ◽  
Author(s):  
F Y Leung ◽  
A R Henderson
Keyword(s):  
Reference Interval ◽  
Matrix Interference ◽  
Linear Calibration ◽  
Standard Curve ◽  
Steady State Temperature ◽  
Analytical Recovery ◽  
Standard Additions ◽  
Assay Precision ◽  
Serum And Urine

Abstract This method for determining aluminum in serum and urine is essentially free from matrix interference and gives a linear response with concentration to at least 500 micrograms/l. Use of a stabilized temperature platform (L'vov platform, Perkin-Elmer Corp.) to approach a "steady-state" temperature, addition of matrix modifiers [especially Mg(NO3)2], and the use of peak area integration all helped substantially diminish spectral interference. With the platform furnace, serum protein concentrations as great as 260 g/L did not interfere with the determination of Al. The within- and between-assay precision (CV) was less than or equal to 3.5% and less than or equal to 7.4%, respectively. Analytical recovery of Al added to serum ranged between 95 and 101% throughout the linear calibration range (to 500 micrograms/L), either when measured directly from the standard curve or by the method of standard additions. The reference interval for Al in 28 healthy subjects was 2-14 micrograms/L (mean 6.5, SD 4.1 micrograms/L), and for 130 patients on hemodialysis, 20-550 micrograms/L (mean 87.5, SD 62.5 micrograms/L).

Rapid Determination of Sulfide in Tannery Wastewater by Flow Injection Spectrophotometry

2014 ◽  
Vol 675-677 ◽  
pp. 310-313
Author(s):  
Dong Yuan ◽  
Da You Fu
Keyword(s):  
Flow Injection ◽  
Spectrophotometric Method ◽  
Rapid Determination ◽  
Tannery Wastewater ◽  
Linear Calibration ◽  
Sulfide Ion ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Good Agreement

A simple and rapid spectrophotometric method for flow injection determination of sulfite in tan wastewater is described. It was based on the fade reaction of sulfide ion with Ag (I)- (5-Bromo-2-pyridylazo)-5-diethyl-aminophenol (5-Br-PADAP) in NaAc-HAc medium. The optimum conditions allow a linear calibration range of 0.01-1.10 μg ml-1sulfide ion. The detection limit is 0.0043 μg ml-1 (S/N=3), and the relative standard deviation for night replicate measurements is 2.1% for 0.5μg ml-1of sulfide ion. The procedure has been applied to the determination of sulfide in tannery wastewater. The results were in good agreement with those obtained by methylene blue spectrophotometric method.

Determination of Hydrogen Diffusivity in Rail Steels by Sub-Scale Microhardness Profiling Technique

2009 ◽  
Vol 293 ◽  
pp. 41-45 ◽  
Author(s):  
Abhijeet Moon ◽  
R. Balasubramaniam
Keyword(s):  
Diffusion Coefficient ◽  
Current Density ◽  
Pure Iron ◽  
Rail Steel ◽  
Hydrogen Diffusivity ◽  
Surface Microhardness ◽  
Ambient Temperatures ◽  
The Difference ◽  
A Current

Hydrogen diffusivity was estimated in three different eutectoid rail steels (C-Mn, Cu-Mo and Ni-Cu-Cr) at ambient temperatures using the technique of sub-surface microhardness profiling after cathodic hydrogen charging in 0.5mol/l sulphuric acid at a current density of 0.1A/cm2 for 24 hours. The increase in the concentration of hydrogen at a certain depth below the surface was related to the microhardness increase at this location as compared to the bulk value. The procedure used to obtain the diffusion coefficient of hydrogen from the microhardness profiles is discussed. The hydrogen diffusivity values in all of the rail steels were found to be similar (of the order of 10-13m2/sec). The estimated hydrogen diffusivity in the rail steel was lower than in pure iron (10-8m2/sec). Possible reasons for the difference are discussed.

scholarly journals A Validated, Rapid HPLC-ESI-MS/MS Method for the Determination of Lycopsamine

2015 ◽  
Vol 10 (7) ◽  
pp. 1934578X1501000
Author(s):  
Nikoletta Jedlinszki ◽  
Dezső Csupor
Keyword(s):  
Quality Control ◽  
Calibration Curve ◽  
Pyrrolizidine Alkaloid ◽  
Validation Period ◽  
Aqueous Samples ◽  
Linear Calibration ◽  
Good Repeatability ◽  
Interday Precision ◽  
Control Samples

The aim of the present work was to develop and validate an HPLC-MS/MS method for the determination of a major pyrrolizidine alkaloid of comfrey (lycopsamine) in aqueous samples as a basis for the development of a method for the determination of absorption of lycopsamine by human skin. A linear calibration curve was established in the range of 1.32–440 ng. The intraday precision during the 3-day validation period ranged between 0.57 and 2.48% while the interday precision was 1.70% and 1.95% for quality control samples. LOD was 0.014 ng and recovery was above 97%. The lycopsamine content of the samples stored for 9 and 25 days at 22°C, 10°C and −25°C did not vary. These results underline the good repeatability and accuracy of our method and allow the analysis of samples with very low lycopsamine content.

scholarly journals Comparison of the Board of Trade ampere-standard balance with the Ayrton-Jones current-weigher; with an appendix on the electromotive forces of standard cells

1908 ◽  
Vol 80 (540) ◽  
pp. 383-389 ◽  
Keyword(s):  
Technical College ◽  
National Physical Laboratory ◽  
Current Strength ◽  
Physical Laboratory ◽  
The Difference ◽  
Set Up ◽  
High Degree ◽  
A Current ◽  
Fair Degree

When the Board of Trade ampere balance was set up and verified in 1894, the platinum weight (marked A) used with the instrument was adjusted so that a current which deposited silver from a 15-per-cent. solution of silver nitrate at the rate of 1·118 milligrammes per second produced, on reversal, a change of force equal to the weight of A. At that period such a current was believed to represent the ampere , viz., 1/10 of a C. G. S. unit, with a fair degree of accuracy. During the last few years a new current weigher, designed at the Central Technical College, has been constructed at the National Physical Laboratory with a precision previously not obtained in any instrument for the absolute determination of current strength, and by means of it the electrochemical equivalent of silver has been determined to a very high degree of accuracy. We therefore considered it of interest to determine the difference between the units of current as measured by the two balances, and at the same time ascertain how nearly the ampere, as measured by the Board of Trade balance, deposits silver at the rate of 1·118 milligrammes per second.

scholarly journals XI. The mobilities of the ions produced by Röntegen rays in gases and vapours

1909 ◽  
Vol 209 (441-458) ◽  
pp. 249-279 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Electric Field ◽  
Diffusion Coefficients ◽  
Negative Ions ◽  
Experimental Methods ◽  
Ionic Mobilities ◽  
Monovalent Ion ◽  
The Difference ◽  
A Current

For various reasons the determination of the velocities in an electric field of the ions produced in gases by the action of Röntgen rays is of fundamental importance in electrical theory. A knowledge of the ionic mobilities the velocities under unit electric intensity) affords information with regard to the structure of the ion; if, in addition, the diffusion coefficients of the ions in various gases are known, the charge associated with the ion can be compared with that carried by the monovalent ion in the electrolysis of solutions. Experimental methods of determining the mobilities of the positive and negative ions were devised not long after the ionising action of the Röntgen rays was known. Rutherford determined the values of the sum of the positive and negative mobilities in a series of gases. Zeleny, by comparing the velocity acquired by the ions in an electric field with that of a gaseous current parallel to the field, succeeded in deducing the values of the difference of the ionic mobilities and also their ratio. In later experiments Zeleny employed a current of gas in a direction perpendicular to the electric field and deduced the absolute values of the mobilities in air, oxygen, carbon dioxide, and hydrogen.

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