Integrate the area above the curve i(t)dt = Q (charge in Coulombs). Then use the Faraday laws to calculate the quantity of substance (mol or equiv) or its mass .
As mentioned above, obtaining the charge transferred and using Faraday's law is the most straightforward way of obtaining the amount of material deposited. However, you must be quite careful with a couple of things, which depend on your particular system: the first is the number of electrons transferred, which is dependent on the deposition reaction, but also, and this is sometimes a little more tricky, you need to make sure that there are no side reactions contributing to the charge. In order to use this method, you are assuming that all of the current you measure is due to your material being deposited, so if you have anything else happening at the electrode, it will introduce errors into your calculations. Common side reactions in metal deposion in aqueous systems, for example, are oxygen reduction or hydrigen evolution.
In my opinion, the use of Faraday's law is for the theoretical amount of metal deposited on the electrode surface since as Daniela commented above the side reactions will be present in aqueous systems.
As practical measurements you can measure the electrode mass before and after the deposition, but you have to be careful with the deposit mass loss. Another option is the control of metal concentration in your solution during the deposition.
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