Embedded mini-analyzer device for in situ wide range heavy metal identification and concentration detection
Metal toxicity is a critical concern in both human health and ecosystem. Many heavy metals are lethal at high concentration. It can also be harmful at trace concentration since accumulating such materials in human organs lead to longterm negative health effects such as cancer, heart disease and h...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/77630/1/FK%202019%2024%20ir.pdf |
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| Summary: | Metal toxicity is a critical concern in both human health and ecosystem. Many
heavy metals are lethal at high concentration. It can also be harmful at trace
concentration since accumulating such materials in human organs lead to longterm
negative health effects such as cancer, heart disease and high blood pressure.
Therefore, heavy metal detection of trace concentration is very important. Heavy
metals can be detected using electrochemical detection system. It consists of electrodes,
potentiostat that controls the electrode and signal processing block. With
the advancement of integrated technology, in-situ electrochemical systems provide
feasible solution for sensitive detection and miniaturized platform. The
potentiostat as main part of the system; read, amplify and control the current flow
through the electrodes.
In this study, the fully differential variable gain potentiostat, would be able to
measure wide range current of different types of electro chemicals, typically from
100 nA to 100 mA and can generate an excitation potential between -3V and +3V.
This potentiostat is designed with a fully differential operational amplifier and
rail-to-rail common-mode range buffer for linearity of output signal.
Voltammetry as electrochemical technique is used in this project for the heavy
metals detection. This designed device was able to perform differential pulse
anodic stripping voltammetry (DPASV) as a sub techniques of voltammetry.
Among many types of voltammetry techniques, differential pulse anodic stripping
voltammetry (DPASV) technique was chosen where a pulse shaped voltage is
applied on the sen- sor and the current through the sensor is measured to determine the concentration and types of heavy metal.
To achieve the ability of in-situ processing of detection, embedded algorithms like
digital FIR filter, multiple peaks finding, peaks classification and linear
regressions have been implemented on an ARM processor. The resulted signals
known as voltammogram and the concentration value will be displayed on a
graphical LCD. Voltammogram is a plot of current reaction with applied voltage.
Tests were carried out for solution with different heavy metals like cadmium (Cd),
lead (Pb) and copper (Cu). A concentration range from 0.5 ppm to 10 ppm of lead
have been used to test the system accuracy and detection limits. The system was
able to detect the heavy metal with correlation factor of 0.99, between the
concentration value and voltammogram current peaks. |
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