Working on Electrical Resistivity Tomography hardware

Dear All,

I am currently working on developing the hardware of electrical resistivity tomography (ERT) system in visualizing the two phase flow in acrylic pipe.

Would appreciate any suggestion on which types of Arduino should I purchase, the functions of Arduino that I want to have is it can measure the voltage difference sequentially (maybe any Arduino can have the multiplexer function in it) and store the data, then the data can be transmitted to the computer.

What is the most economical and efficient Arduino that I should use in developing the above mentioned sensor?

You didn't mention the required resolution of the digitized signals. Arduinos come with 10 or 12 bit ADC resolution, and somewhat stable voltage references. For higher resolution or stability you can add an external ADC.