Teaspoon
There is more than one type of teaspoon:
A US teaspoon is 4.93ml: US teaspoon
A UK teaspoon is 5ml: UK teaspoon
Microliters
Microliters are a unit of volume in the metric system used to measure very small amounts of liquid. One microliter is equal to one millionth of a liter. This tiny unit of measurement is often denoted by the symbol μL. To put it into perspective, a single drop of water is roughly equivalent to about 50 microliters.