I have a set of data in text file which is in voltage... I m in need to convert that data to micropascal.. please help me. 

What is voltage (other then a measurement of electrical power)? What format is the data in? MicroPascal is, I'm guessing, a programming language. If so you don't convert data to a programming language, you convert to data format.

A micropascal is a unit of pressure. ashabanu: are you using some sort of pressure gauge that produces voltages, and you're trying to correlate those voltage readings to pressures? If so - have you tried to run a correlation among some base line readings (known pressures producing a resulting voltage)? Yet the subject mentions decibels - why? Please clarify your question so that we may help you better.

A micropascal is a unit of pressure.

Oops ;)