الفهرس 
LITERATURE SURVEYOnly 14 pages are availabe for public view
 |  | from | 176 |  |  |
| | | from | 176 | | |
Abstract
SUMMARY
The present thesis describes the performance characteristics of screenprinted
and carbon paste electrodes for determination of Fe(III) ion. These
electrodes are utilized for the determination of Fe(III) ions in pure form and
water samples.
Each screen-printed electrode is composed of a mixture of solvent, the
binding material polyvinyl chloride, graphite powder, plasticizer and ionophore,
while each carbon paste electrode consists of a paste, which is composed of
graphite powder, plasticizer and ionophore. The thesis comprises three chapters:
(1) Chapter I: A literature survey was presented on Fe(III) ions concerning
their determination in various samples. Also, it includes introduction concerning
the theoretical bases for preparation and uses of different types of ion-selective
electrodes and its general properties.
from this literature survey, it was obvious that there is no previous work
using those modified screen-printed and carbon paste electrodes for the
determination of Fe(III) ions.
(2) Chapter II: Includes the experimental part, the materials, solutions,
instruments used and working procedures. It contains full details about
experimental conditions for potentiometric determination of Fe(III) ions in pure
form and water samples, also full details for preparation of screen-printed and
carbon paste electrodes. The preparation of ionophores is also mentioned.
(3) Chapter III: A simple, rapid and reproducible method for
potentiometric determination of Fe(III) ions using modified screen-printed and
SUMMARY RE
109
carbon paste ion-selective electrodes was proposed. The screen-printed and
carbon paste sensors were utilized as indicator electrodes for the potentiometric
titration of Fe(III) ion. The preparation of the screen-printed and carbon paste
electrodes as well as the factors affecting the electrodes performance with this
technology are shown and discussed in details. These factors include:
1-Effect of plasticizer type: When these electrodes are used to monitor the
potentiometric titration of Fe(III) ion, TCP and DOS are selected as the best
plasticizers. This is indicated by high potential break at the end point, which is
related to its high dielectric constant.
2- Effect of ionophore content: 15 and 10 mg of methyl 6-(hydroxymethyl)
picolinate ionophore are the best concentrations for Fe(III)-MCPEs and MSPEs,
respectively.
3-Effect of pH: 3 – 8 is the best pH range for electrodes (I, II, III and VI).
4-Effect of soaking time: The Fe(III) ion-selective electrodes need to be soaked
in 10-3 Fe(III) solution before application in the potentiometric titration of
Fe(III) ion.
5- Range of concentration: 1.0×10-6-1.0×10-2 mol L-1 with a detection limit of
1.0×10-6 mol L-1 and 2.6×10-7-1×10-2 mol L-1 with a detection limit of 2.6×10-7
mol L-1 for MCPEs and MSPEs, respectively.
6- Effect of temperature: 0 - 60 °C are the best temperature ranges for Fe(III)-
MCPEs and MSPEs.
7- Response time: 11, 5, 6 and 8 seconds for Fe(III) electrodes I, II, III and IV,