A method of pipetting an accurate quantity of liquid comprising the steps of drawing water into a pipetting chip (2) from a liquid container (8), drawing air into said tip first slowly at a first rate and then quickly at a second rate to turn said drawn water into a mist of drops in said tip (2) and increase the relative humidity of the air in said tip (2), waiting a preset time period, and drawing a tested liquid into said tip (2).This makes the quantity of vapor of the tested liquid in said tip (2) very small and constant and thus the accurate quantity of tested liquid can be pipetted.