I have a 9v battery split in the middle to get + and - supply for opamp. The same battery is regulated 5v and connected to vcc and gnd of arduino. How to connect the virtual ground to arduino now? Will this cause problems? Opamp output never goes to negative..
In the diagram below I am concerned this will short out the bottom resistor. Do I need separate supplies?
Keep it like this. Use your vrtual ground for your opamp inputs.
Realize that you will need to send negatve voltage (relative to your virtual ground) to your arduino. Anything above 0.5V will damage your arduino (as it sees 1V relatve to virtual ground as 5.5V).
You cannot sink large current to your virtual ground...
That is als why you cannot use your virtual ground as arduino ground.
Then how can arduino adc take any valid measurements without using virtual ground....every measurement will be relative to that ground right? I am planning to use the opamp as a differntial amplifier so arduino somehow needs to get the result.
As long as you know how arduino ground relates to virtual ground, that is not a problem.
If you use a rail to rail opamp you can also feed it with 5V and gnd from arduino.
You could feed it with 5V from arduino, -4V from your battery (5V - 9V), and gave gnd a just a bit from the middle.
Or you organize a real symmetric power supply... in that case you can share the middle gnd with arduino gnd.
It will all depend a bit on what exectly you want to accomplish with the opamp.
It will
How to connect the virtual ground to arduino now?
You cannot
Will this cause problems?
Yes
Opamp output never goes to negative.
Then you don't need a split supply
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Is it a single supply diff amp?
Are both inputs positive or does one or both go negative?
Nope dual rail.
@md_imran_sarkar
Then the simplest solution is to use two 9V batteries.
GND is common to both the op-amp circuit and the Arduino.
Connect the +9V to the Arduino Vin, no need for a 5V regulator
Many dual supply op-amps can work with unsymmetrical supplies.
If the output will never go negative then you could also use this circuit.
I think I will use separate power supplies to isolate the loads.
Sure, if you don't want to use batteries that will also work.
Just make sure the outputs are isolated, because you are connecting the positive of one to the negative of the other.
Hi, @md_imran_sarkar
Can you please tell us what your project is?
What is the differential amplifier amplifying?
Thanks... Tom... 
Why do you need a split supply?
What is the range of each of the signal inputs relative to ground?
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