Citation
Muhammad, Aliyu
(2016)
Fabrication of electrochemical sensor based on multi-walled carbon nanotubes/gold nanoparticles for voltammetric detection of amoxicillin and thiamphenicol residues in bovine milk.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
Antibiotic residues in milk are of great concern to health regulatory agencies, milk
consumers and dairy farmers due largely to their effects ranging from allergic
reactions, antibiotic resistance and ability to interfere with the technological properties
of milk used for manufacturing fermented products. The conventional methods used
in detecting these residues suffered some limitations of being expensive, time
consuming and lack the capacity for point of care analysis.
A bulk scale synthesis of nanocomposites containing gold nanoparticles (AuNPs) and
multi-walled carbon nanotubes (MWCNTs) using ethylenediamine (en) as a cross
linker between MWCNTs and AuNPs is presented here. The amine groups in en were
used as growth point for the AuNPs synthesis through electrostatic attraction between
the amine group (NH4+) and AuCl4- while sodium citrate acts as a reducing agent. The
results showed that the size and distribution of AuNPs on the surface of the MWCNTs
is greatly affected by the amount of HAuCl4. Morphology of the synthesized
nanocomposites was characterized by Field Emission Scanning Electron Microscopy
and Transmission Electron Microscopy while the elemental composition and
crystallography of the composites were investigated by Energy Dispersive X-ray, Xray
Diffraction, Ultraviolet Visible, Thermal Gravimetric Analysis and Raman
spectroscopic techniques. The nanocomposite was used to modify a screen printed
electrode. Electrochemical characterization of the electrode revealed that the
nanocomposites have increased its electro-active surface area and conductivity. The
fabricated sensor was applied for the voltammetric detection of amoxicillin in Bovine
milk samples by adsorptive stripping voltammetry (AdSV). The result shows that the
synthesized nanocomposites had induced a remarkable synergetic effect towards
electro-oxidation of amoxicillin. Under optimized experimental conditions, (0.1 M
phosphate buffer of pH 7.0, accumulation potential -0.4 V, accumulation time 180 s.)
AdsV measurements of amoxicillin showed a wide linear dynamic range within the concentration range of 0.2-30 μM. Two linear calibration ranges from 0.2-10 μM and
10-30 μM were observed with equations of Ipa (μA) = 2.88 C (μM) + 1.2017; r =
0.9939 and Ipa (μA) = 0.88 C (μM) + 22.97; r = 0.9973 respectively. The limit of
detection (LOD) and limit of quantification (LOQ) were calculated as 0.015 μM and
0.149 μM, respectively. Differential pulse voltammetric technique (DPV) was
employed for thiamphenicol detection. The result shows that the synthesized
nanocomposites also induced a remarkable synergetic effect for the oxidation of
thiamphenicol. Under optimized experimental conditions, (0.1 M citrate buffer of pH
6.0, accumulation potential -0.7 V, accumulation time 150 s). DPV measurements of
thiamphenicol shows a wide linear dynamic range within the concentration range of
0.1-30 μM. Two linear ranges were recorded from 0.1- 10 μM and 10-30 μM with
equations of Ipa (μA) = 0.9888 C (μM) + 1.2563; r = 0.9939 and Ipa (μA) = 0.216 C
(μM) + 7.36; r= 0.9973 with LOD and LOQ of 0.003 μM and 0.01.0 μM respectively.
The fabricated sensor was applied for determination of amoxicillin and thiamphenicol
in Bovine milk with satisfactory recovery results which compared favorably with
HPLC standard method. This suggests its applicability as an alternative means of
detecting amoxicillin and thiamphenicol in Bovine milk samples for environmental
monitoring and quality control processes.
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Additional Metadata
Item Type: |
Thesis
(Doctoral)
|
Subject: |
Electrochemical analysis |
Subject: |
Biosensors |
Subject: |
Nanoparticles |
Call Number: |
FS 2016 64 |
Chairman Supervisor: |
Professor Nor Azah Yusof, PhD |
Divisions: |
Faculty of Science |
Depositing User: |
Ms. Nur Faseha Mohd Kadim
|
Date Deposited: |
26 Jun 2019 02:02 |
Last Modified: |
26 Jun 2019 02:02 |
URI: |
http://psasir.upm.edu.my/id/eprint/69266 |
Statistic Details: |
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