(Picture taken from http://www.als-japan.com/1031.html)Electrodes are electrical conductors that can be used for various purposes such as electrocardiography (ECG) and chemical analysis using electrochemical methods. There are different types of electrodes available in the market but the ones that I have been using are the gold (Au) electrodes.
In order to ensure that the Au electrodes are fit for use, they are polished to remove unwanted chemical residues from previous use. New electrodes of course, do not need to be polished. Polishing is done using alumina powder on a nylon pad. The electrodes are held perpendicular to the nylon pad (with Au in contact with the pad that has alumina powder.) Then for a desired time (eg 10 min each), these electrodes are polished in a figure of 8 or circular motion. The particles in the alumina powder will remove the residues on the gold surface. In addition, nano-strip can be used too. By incubating the electrodes in nano-strip for 15 min, any remaining organic residues are removed.
So how do you know if the electrodes are clean? Electrochemical signals are measured with an electrochemical workstation. A clean Au electrode should give a high electrochemical signal while a Au electrode covered with residues will give a low signal because these residues will slow down the transfer of electrons between the electrode and electrolyte.
(Picture taken from http://www.uni-muenster.de/Physik.PI/DeCola/equipment.html)Yvonee Chew 0703189A
Hi Yvonee!
ReplyDeletewanna ask you does it comes with reference electrodes too?
because in my lab, i learnt a little bit about electrochemistry too and they mentioned about presence of reference electrode :))
THANKS!
stella
0701059H
Hello Stella,
ReplyDeleteI'm not if it comes with the reference electrodes but the reference electrodes are used as part of the three-electrode system that is connected to the workstation to measure the electrochemical signals.
The three-electrode system consist of a working electrode (which is the gold electrode in this case), a reference electrode and a counter electrode.
Yvonee Chew
0703189A
What is the difference of a gold electrode and a normal electrode, other than the colour?
ReplyDeleteIs there any significance if i would to use the gold electrode rather than the normal electrode or vice versa?
Alvin
Hello Alvin,
ReplyDeleteAll electrodes are made of different inert materials (gold, platinum, glassy carbon etc.) that are located in the middle. Hence there isn't any electrode that is considered normal.
For each type of electrode, they have different properties such as electrical conductivity. Depending on the needs of the project, different electrodes are used. Some electrodes may lower background signals (such as indium tin oxide) while others may higher background signals (such as gold).
Yvonee
0703189A
Hi Yvonee!
ReplyDeleteWhy is it that we must use the transfer of electrons between electrodes and electrolytes? What is the purpose of doing that? How does this principle help or apply in electrocardiography?
QINGLING
Hey Yvonee,
ReplyDeleteWhat are the differences in the types of metal used? Is the effectiveness of the ECG based on the charges of individual metals? If so, which metal is commonly used in the market?
Felicia
0703345I
Hi Qing Ling,
ReplyDeleteI think my post is a little misleading so I've corrected it to aid understanding.
Electrodes can be used in many areas such as ECG and chemical analysis using electrochemical methods. In electrochemistry, we measure the transfer of electrons between electrode and electrolyte. In ECG, it measures the electrical signals of the heart.
As for purpose, electrodes in electrochemistry enables us to understand the reaction that occurs at molecular levels. Eg. if an electrode is modified to be able to capture a protein, transfer of electron from the electrolyte to the electrode can be physically hindered if the protein has bound. Hence presence of protein will cause differing electrochemical signals produced. This is just one of the many possibilities how use of electrodes can be exploited.
As for ECG, I am unable to provide much insights because I'm attached to a research lab. I've read up a little and found that electrodes are placed onto the skin of the arms, legs etc to measure the electrical activity (depolarisation and repolarisation) of the heart. This can aid the medical team to determine the heart condition.
Hope it helps:)
Yvonee
0703189A
Hi Felicia,
ReplyDeleteI am unable to provide much insights on ECG because I'm attached to a research lab. I've read up a little so I hope it helps.
Yes, ECG electrodes can be made of different materials but stainless steel is most commonly used. As different materials have different properties (eg electrical conductivity), yes, measurements taken from machine A using material A electrodes should not be compared to reference range for material B electrodes because this can lead to misdiagnosis. However, it is unlikely the case as stainless steel is most commonly used.
Hope it helps:)
Yvonee
0703189A
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