Understanding an opamp circuit
A 10-bit ADC has \$ 2^{10} \$ = 1024 steps. In binary it's going to go from 00 0000 0000 to 11 1111 1111.

Your analog ref is 2.495 V (on figure 2). \$ \frac {2.495}{1024} = 2.4~mV/step \$ on ADC input.

At maximum signal gain of 19,520 your signal resolution is \$ \frac {2.4~mV}{19520} = 123~nV = 0.123~\mu V \$.