A comparison of spectrophotometric methods for the determination of uranium

1991 ◽  
Vol 56 (4) ◽  
pp. 774-784 ◽  
Author(s):  
Luděk Jančář ◽  
Irena Jančářová ◽  
Josef Havel

Some spectrometric and extraction photometric methods for the determination of uranium were compared using pure solutions, a model sample and samples of surface waters and waste waters; the characteristics examined included sensitivity, accuracy, repeatability, time demands and tediousness. Among the most sensitive methods are those based on the use of triphenylmethane dyes in the presence of surfactants; uranium is separated from associate ions by extraction into tri-n-octylamine in an organic solvent and subsequently re-extracted into an aqueous phase. The results compare well with those attained by using methods given in the Czechoslovak State Standard and in the standard of the Czechoslovak Uranium Industry corporation.

1999 ◽  
Vol 71 (11) ◽  
pp. 2161-2176 ◽  
Author(s):  
B. Ya. Spivakov ◽  
T. A. Maryutina ◽  
H. Muntau

Environmentally significant phosphorus species in water and phosphorus fractions in sediments are briefly discussed and the methods for their determination are described. One of the most critical analytical steps is the separation of the different forms which, after conversion into orthophosphates, may be determined by a multitude of various techniques. Spectrophotometric methods are often preferred for routine analysis. Several rapid automatic methods for the separation and determination of orthophosphate, linear polyphosphates, cyclic condensed phosphates and lower oxidation state anions of phosphorus, which may exist in natural and waste waters, have been developed. They are mainly based on the use of flow-injection analysis, high-performance liquid chromatography including ion chromatography, capillary electrophoresis and a few of other techniques. These methods have been described and critically evaluated.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
K. Susmitha ◽  
M. Thirumalachary ◽  
T. Charan Singh ◽  
G. Venkateshwarlu

Tenofovir disoproxil fumarate is a nucleotide reverse transcriptase inhibitor that has activity against the hepatitis B and HIV viruses. Three simple and sensitive extractive spectrophotometric methods have been described for the assay of tenofovir disoproxil fumarate either in pure form or in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes of the drugs with triphenylmethane dyes, namely, bromothymol blue (BTB), bromophenol blue (BPB), and bromocresol purple (BCP) in acidic medium. The extracted complexes showed absorbance maxima between 410 and 415 nm. Beer’s law is obeyed in the concentration ranges 1.5–25, 1.0–25, and 1.25–25 μg mL−1 with BTB, BPB, and BCP, respectively. The effectc of concentration of dye, pH, and interference of excipients have been studied and optimized. The limits of detection and quantification have been determined. All three methods are validated as per the guidelines of ICH. The methods have been applied to the determination of drug in commercial tablets and results of analysis were validated statistically through recovery studies.


1984 ◽  
Vol 32 (10) ◽  
pp. 1107-1112 ◽  
Author(s):  
E T Mays ◽  
R C Feldhoff ◽  
G S Nettleton

In phase partition fixation tissue is immersed in an organic solvent at equilibrium with an aqueous phase containing a fixing agent. By using radioisotope labeling techniques the effects of phase partition fixation on protein retention during fixation of tissue with formalin and glutaraldehyde have been determined and compared with those of standard aqueous fixation using these fixatives. It has been shown that retention of protein in tissue during phase partition fixation was as good or better than during aqueous fixation. Improved retention provides further evidence that phase partition fixation may be a useful alternative to aqueous fixation.


1984 ◽  
Vol 49 (9) ◽  
pp. 1974-1989 ◽  
Author(s):  
Milan Pištělka ◽  
Bohumil Stojek ◽  
Josef Havel

The influence of various tensides on the sensitivity of the reaction of uranyl with chromatographically pure Eriochromazurol B (2'',6''-dichloro-3,3'-dimethyl-4-hydroxyfuchsone-5,5'-dicarboxylic acid) was studied and considerable bathochromic and hyperchromic effects were observed. The reaction is most sensitive in the presence of cetyltrimethylammonium or certylpyridinium bromide. Based on the study of the equlibria and optimization of the conditions, a method is suggested for the determination of uranium traces in waters consisting in the measurement of absorbance at 624 nm at pH 5. With the molar absorptivity value of 136 000, the method ranks among the most sensitive spectrophotometric methods of determination of uranium in general. The uranium traces in waters can conveniently be extracted with tri-n-octylamine and reextracted into an aqueous phase. For 10 ml samples, the detection limit is 0.025 ppm uranium. The results obtained are evaluated statistically.


2016 ◽  
Vol 10 (4s) ◽  
pp. 621-629
Author(s):  
Valentina Pidlisnyuk ◽  
◽  
John Harrington JR ◽  
Yulia Melnyk ◽  
Yuliya Vystavna ◽  
...  

The article focuses on examining the influence of fluctuations in annual precipitation amount on the quality of surface waters. Water quality was estimated with data on BOD, COD and phosphate–ion concentration within five selected regions of Ukraine. Analysis of the precipitation data (1991 – 2010) showed different regional trends. Using the statistics, determination of the interconnection between precipitation amount and water resources quality were done. The obtained regularities and associated uncertainties can be used for prediction of changes in water resource quality and as a guide for future adaptation to possible climate change.


Author(s):  
Abbas Shebeeb Al-kadumi ◽  
Sahar Rihan Fadhel ◽  
Mohammed Abdullah Ahmed ◽  
Luma Amer Musa

We proposed two simple, rapid, and convenient spectrophotometric methods are described for the determination of Amoxicillin in bulk and its pharmaceutical preparations. They are based on the measurement of the flame atomic emission of potassium ion (in first method) and colorimetric determination of the green colored solution for manganite ion at 610 nm formed after reaction of Amoxicillin with potassium permanganate as oxidant agent (in the second method) in basic medium. The working conditions of the methods were investigated and optimized. Beer's law plot showed a good correlation in the concentration range of 5-45 μg/ml. The detection limits and relative standared deviations were (2.573, 2.814 μg/ml) (2.137, 2.498) for the flame emission photometric method and (1.844, 2.016 μg/ml) (1.645,1.932) for colorimetric methods for capsules and suspensions respectively. The methods were successfully applied to the determination of Amoxicillin in capsules and suspensions, and the obtained results were in good agreement with the label claim. No interference was observed from the commonly encountered additives and expectancies.


2020 ◽  
Vol 16 ◽  
Author(s):  
Mamdouh R. Rezk ◽  
Mina Wadie ◽  
Soheir A. Weshahy ◽  
Mahmoud A. Tantawy

Background: Alfuzosin is recently co-formulated with solifenacin for relieving two coincident urological diseases, namely; benign prostate hyperplasia and overactive bladder Objective: Herein, green, simple and rapid spectrophotometric methods were firstly developed for simultaneous determination of the two cited drugs in their co-formulated pharmaceutical capsule Methods: Alfuzosin, which is the major component in the dosage form, was directly assayed at its extended wavelength at 330.0 nm. The challenging spectrum of the minor component, solifenacin, was resolved by five spectrophotometric methods, namely; dual wavelength (DW) at 210.0 & 230.0 nm, first derivative (1D) at 222.0 nm, ratio difference (RD) at 217.0 - 271.0 nm , derivative ratio (1DD) at 223.0 and mean centering of ratio spectra (MC) at 217.0 nm Results: The Proposed methods were successfully validated as per ICH guidelines. Alfuzosin showed linearity over the range of 4.0 - 70.0 μg/mL, while that of solifenacin were 4.0 - 50.0 μg/mL for DW, 2.0 - 70.0 μg/mL for 1D and RD methods, 1.0 - 70.0 μg/mL for 1DD and 4.0 - 70.0 μg/mL for MC method. Statistical comparison with their official ones showed no noticeable differences. The methods showed good applicability for assaying drugs in their newly combination. Besides eco-scale, the greenness profile of the methods was assessed and compared with the reported spectrophotometric one via the newest metric tool; green analytical procedure index (GAPI). Conclusions: The proposed methods are superior in not only being smart, accurate, selective, robust and time-saving, but also in using distilled water as an eco-friendly and cheap solvent


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