Abstract: A measured amount of a first fluid is metered into a measured amount of a second fluid by a method where a fluid is confined within a first chamber and a plunger of predetermined volume is mechanically moved into the chamber to displace a first measured amount of fluid after which a second plunger is mechanically moved into a defined volume of the chamber to displace a second volume of fluid therefrom different from the first volume whereupon the first and second volumes can be mixed in predetermined proportions.

Abstract: A method of metering and dispensing a first liquid, using a probe having an aspiration tip defining a tip chamber. The aspiration tip chamber is sized so as to be capable of holding and metering at least two largely different volumes of a first liquid. In the method a filler liquid is introduced into a portion of the chamber and a first liquid is aspirated in a predetermined amount into the chamber, so that a predetermined amount of the first liquid can be metered and dispensed with high accuracy and precision. The chamber is capable of being used for two largely different doses of the first liquid. Additional liquids can be aspirated along with the filler liquid. The filler using can be a reactant, a cleaner or the like.