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LMC6082: Potentiostat for polarographic dissolved oxygen probe

Part Number: LMC6082
Other Parts Discussed in Thread: LMP91000, LMC6081, , LMC6482, LMP2232, LMC6492

Dear Forum,

I am currently trying to design a dissolved oxygen device using a 2-wire polarographic probe.  The max output of this probe is roughly 40-80 nA when biased at 670 mV.  I was going to use the LMP91000 AFE in my design with a 5 meg Resistor for the TIA, but I've gotten feedback k the OpAmps in this chip are inot deal for such a high impedance signal.  

So I was planning to recreate the circuit shown below with a low input offset current OpAmp like the LMC6082 (or LMC6081).  I would dispense with amplifier A1 and simply send VE- to ground.  I would feed A2 with a 670 mV potential from a buffered VDAC to the noninverting terminal of TIA and configure the rest of A2 as shown in the figure below:  Inverting input tied to VE+ and through the R(TIA) resistor to Output.  I would probably include a Cap (2.2-22 pF) in parallel with R(TIA) as well.

My question is whether my choice of OpAmp is wise and if this design is inherently flawed.  Cost at this level is not a huge issue, and I'm looking at the LMC6081/2, LMC6492, LMP2232, and LMC6482.