6 input differential ADC - Gas sensing

Hi Everyone,

I have acquired a Gas sensing board from Alphasense for a project I'm working on.

This board will produce six analogue voltages between -5v and 5v, depending on sensor type and gas concentration. I would like to measure these with an Arduino (and external ADC).

http://www.alphasense.com/WEB1213/wp-content/uploads/2015/11/AFE.pdf

Is there any well supported ADCs out there that can do this. Ideally more than 10 bit, the digital logic is 3V3. I don't want to have to write a library as this is only for a prototype before integration into a product.

I don't want to have to build 6 analogue op-amp circuits to shift the voltage to all positive. As this is a lot of work for a prototype.

Alphasense Board:
http://www.alphasense.com/WEB1213/wp-content/uploads/2015/11/AFE.pdf
Alphasense Circuit:

Any suggestions are welcome,
Cheers

The docs are not very helpful. In detail I'm missing a circuit diagram and application note for connecting the module.

And also ....There are a few little A/D boards out there if you google ā€œ Arduino and A/Dā€ The likes of Sparkfun sell them , some include multiplexers to read several channels.