I= KINETIC DETERMINATION OF IRON AND SPECTROPHOTOMETRIC DETERMINATION OF MERCURY BY EXPLOITING THE REACTION OF NEUTRAL RED
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Title of Thesis
KINETIC DETERMINATION OF IRON AND SPECTROPHOTOMETRIC DETERMINATION OF MERCURY BY EXPLOITING THE REACTION OF NEUTRAL RED

Author(s)
M. Nasiruddin Khan
Institute/University/Department Details
Department of Chemistry/ University of Karachi
Session
2006
Subject
Chemistry
Number of Pages
127
Keywords (Extracted from title, table of contents and abstract of thesis)
neutral red, iron, mercury, nr, dyes

Abstract
A catalytic kinetic determination of Iron (11) and spectrophotometric determination of Mercury (11) were performed by exploiting the reactions of Neutral Red (NR). The iron catalyzed oxidation of NR with potassium bromate was studied kinetically by using fixed time method. The reaction was followed by measuring the decrease in absorbance at 535 nm. The effect of surfactants, salt effect, pH, and reagent concentration were investigated to achieve the selectivity and sensitivity of the analytical procedure. Under optimized conditions ( 4.2 x 10-5 mol.L-1 NR, 1.4 x 10-3 mol.L-1 KBrO3, 1.5 x 10-2 mol.L-1 cationic surfactant, 0.5 mol.L-1 LiCl and pH 2.60 at 30°C), iron (11) was determined in the range 0.1 to 0.5 µg mL-1 with a detection limit of 0.019 µg mL-1 and a relative standard deviation (n=6) 1.02 % for 0.2 µg mL-1 Fe(II). The influence of foreign ions on the accuracy of the results was investigated. The developed method is extremely sensitive, selective and simple. The method was applied successfully to the determination of iron in the pharmaceutical and synthetic samples. The results showed good agreement with those obtained by atomic absorption spectrophotometer (AAS). To elucidate the reaction mechanism involved in the selected reaction, detailed kinetic studies were performed under pseudo-order conditions and thermodynamic parameters were obtained.

The reaction between NR and Hg (11) was investigated for the direct spectrophotometric determination of trace Hg (11). The use of the anionic surfactant, sodium dodecyl sulphate (SDS) was useful to increase the sensitivity of the analysis. The effects of the other parameters to optimize the analytical conditions were also found. The calibration plot was linear up to 1.0 µg mL-1 and the average molar absorption coefficient was found to be 2.2 x 104 L morl-1 cm-1 with regression equation of ”A = 0.2116C (µg mL-1) + 0.0023 and R2 = 0.9959 at 272 nm The detection limit obtained was 0.013 µg mL-1 and the relative standard deviation was 1.13 % for 0.30 µg mL-1 Hg (11) (n=6). The proposed reaction has been employed in the determination of mercury in plant, soil and synthetic samples. Results were also verified by AAS method using hydride generation technique (MHS-10) system.

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3827.37 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
132.03 KB
2 1 Introduction 1
148.55 KB
  1.1 Aim Of Work 1
3 2 Literature Review 6
932.6 KB
  2.1 Overview 6
  2.2 Dyes 14
  2.3 Physical And Chemical Properties Of Iron & Mercury 17
  2.4 Surfactant 21
  2.5 Previous Works 24
4 3 Experimental 41
188.45 KB
  3.1 UV-Visible Spectrophotometer 41
  3.2 Atomic Absorption 41
  3.3 Equipments 43
  3.4 Reagents 43
  3.5 Composition Of pH 2.60 Buffer 43
  3.6 Composition pH 6.60 Buffer 43
  3.7 Preparation Of Neural Red Solution 43
  3.8 Preparation Of Potassium Bromate Solution 44
  3.9 Preparation Of Cationic Surfactant 44
  3.10 Preparation Of Lic1 And AlCl 3 Solution 44
  3.11 Preparation Of Fe( Ii) Solution For Aas 44
  3.12 Preparation Of (Hg )II Solution For AAS 44
  3.13 Sample Preparation For Iron Determination 45
  3.14 Sample Preparation For Mercury Determination 45
  3.15 Procedure For Fe( II) Analysis 46
  3.16 Procedure For Hg( II) Analysis 46
  3.17 Standard Atomic Absorption Conditions For Fe And Hg 47
5 4 Results And Discussion 48
2586.42 KB
  4.1 Catalytic Kinetic Determination Of Fe( Ii) 48
  4.2 Analytical Aspects And Statistical Measurements For Fe( Ii) 80
  4.3 Spectrophotometric Determination Of Hg( Ii) 101
  4.4 Analytical Aspect And Statistical Measurements For Hg( Ii) 104
  4.5 Conclusion 115
  4.6 References 116
  4.7 Acknowledgements 123
  4.8 Curriculum Vitae 127