الفهرس 
Summary
SERS detection of certain dyes in sequential injection analysis.Only 14 pages are availabe for public view
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Abstract
The present work is concerned with Raman spectroscopy and some of its
applications. The thesis comprises four main chapters in addition to an introduction
and scope of investigation:
Introduction:
Raman spectra are acquired by irradiating a sample with a powerful laser
source of visible or near-infrared monochromatic radiation. During irradiation, the
spectrum of the scattered radiation is measured at some angle (often 90 deg) with a
suitable spectrometer. At the very most, the intensities of Raman lines are 0.001 %
of the intensity of the source; as a consequence, their detection and measurement
are somewhat difficult.
Surface enhanced Raman spectroscopy (SERS) involves obtaining Raman
spectra in the usual way on samples that are adsorbed on the surface of colloidal
metal particles (usually silver, gold, or copper) or on roughened surfaces of pieces
of these metals. Raman lines of the adsorbed molecule are often enhanced by a
factor of 103 to 106 times.
Chapter I: It contains two parts,
Part 1: SERS detection of certain dyes in sequential injection analysis.
SERS technique was successfully combined with SIA with a full automated
system using LabView software. In-situ photo-reduction of silver ions was
developed to produce a SERS substrate. The whole setup was full computer
controlled by using ATLAS software. The proposed method studied the
enhancement effect of the photo-reduced SERS spot with the elimination of the
memory effect that was produced in all the flowing systems. In order to test the
success of the proposed method, two applications were carried out. The developed
method was applied on certain dyes like Cu(PAR)2 complex, rhudamin6G and
methylene blue.
Different variables affecting the SERS intensity of Cu(PAR)2 complex, such
as carrier’s concentrations, flow rate and the volume of the injected analyte were
studied.
A validation study of the developed method was performed. Under the
optimal conditions, the calibration curve for the standard Cu(PAR)2 complex was
constructed. The obtained calibration curve was linear in the range of 2.5-100
μg/ml with a good correlation coefficient (r= 0.9992). Limit of detection (LOD)
and limit of quantitation (LOQ) were 0.7 and 2.0 μg/ml, respectively. It was found
that; the method is precise and robust.
Part 2: Combination of SERS and SIA for simultaneous determination of
aspirin and vitamin C in bulk and in pharmaceutical dosage forms.
The combination between SERS and SIA was applied for the quantitative
determination of aspirin and vitamin C simultaneously in bulk and dosage forms.
All variables affecting the SERS intensity of both studied drugs include; the
carrier’s concentration, flow rate and the diluting solvents were studied.
A validation study of the proposed method was performed. Under the
optimal condition, calibration lines of the studied drugs were constructed. The
obtained calibrations curves were linear in the range of 100-500 ng/ml aspirin
(r=0.9997) and 10-110 ng/ml vitamin C (r=0.9991). It was found that; the method
is considered precise and robust.
Different commercial dosage forms were analyzed using the proposed
method. Excellent results were obtained after comparing the F- and t- values of the
proposed and reported methods.
Chapter II: SERS for monitoring silver nanoparticles-induced antibacterial
effect.
The ability of SERS method in the analysis of the antibacterial effect of
different shapes of AgNPs was described. Different reduction reactions were.
carried out to produce different shapes of AgNPs. It was found that there is a
relation between the geometry of the prepared AgNPs and the toxicity of it on
Gram negative bacteria. Three different reference methods were carried out in
order to test the effect of the three shapes of AgNPs on E.coli as a model example
of Gram negative bacteria.
Zone inhibition, growth curve and SERS methods were applied using the
same concentration ranges of the prepared AgNPs in addition to Ampicillin as a
positive control. The sensitive changes in the SERS spectra of the studied E.coli
treated with the tested AgNPs allowed the suggestion of the mechanism of
antibacterial effect of the prepared AgNPs. The effect of water chemistry on the
toxicity of the studied AgNPs was tested.
It was found that; the hexagonal shape of AgNPs is more toxic on the
studied E.coli than the spherical and triangular NPs. This may be due to the acute
edges of the hexagonal-AgNPs allow it to penetrate the bacterial cell wall and
inhibit the protein synthesis which lead to cell death.
Chapter III: Application of SERS as a stability indicating assay of some
penicillins.
This is the first trial of application of SERS as a detection and quantitation
tool in the stability indicating assay of some penicillins, named, penicillin G,
ampicillin and carbenicillin. The enhancement effect of the SERS monitoring was
based on the hydroxylamine AgNPs which act as a SERS substrate. Penicilloic
acid, the main degradation product, was reported as the main cause of allergic
reactions after treating with some type of penicillins. The finger printing
identification tool of the Raman spectroscopy allowed the proposed method to insitu
detect the changes in the structure of the intact ampicillin as a representative
example of the studied penicillins. The results obtained with the proposed SERS
method were confirmed with LC/MS spectroscopy as a comparative method to
elucidate the degradation products.