If I wanted to dispense 18.3 micro liters would I use a p-100 choosing from p-10, p-100 and p-1000?

Answer 1

Definitely a p-100. Here's why:

A p-10 only dispenses up to 10 microliters. A p-1000 dispenses up to 1,000 microliters, but it is not accurate enough to dispense 18.3 microliters. (The general rule is to NOT go below 10% of its capacity, so that would be 100 microliters.)

So, the p-100 is the right choice.