Method and apparatus for dispensing low nanoliter volumes of liquid while minimizing waste

A method for dispensing low nanoliter volumes of a plurality of liquids into a plurality of microplates, each microplate having a plurality of sample wells, comprising:

• aspirating a volume of each of a plurality of liquids from samples of the liquids into a plurality of syringes, each syringe being associated with one of the liquids;
• returning a volume of each of the aspirated liquids from the plurality of syringes to the samples, wherein the returned volume is at least 80% of the aspirated volume, and a volume of each of the aspirated liquids is retained in each liquid's associated syringe;
• dispensing a first low nanoliter volume of the retained liquid from each associated syringe into sample wells of a first microplate, wherein the dispensed first volume is not more than 10% of the aspirated volume;
• and
• dispensing a second low nanoliter volume of the retained liquid from each associated syringe into sample wells of a second microplate, wherein the dispensed second volume is not more than 10% of the aspirated volume.

An apparatus for dispensing low nanoliter volumes of a liquid, the apparatus comprising one or more receptacles for aspirating and dispensing a liquid and a controller that directs the apparatus to:

• aspirate a volume of liquid into a receptacle from a sample of the liquid;
• return a substantial portion of the volume of the aspirated liquid to the sample, the returned volume of the liquid being less than the aspirated volume so that a volume of liquid is retained in the receptacle;
• and
• dispense a low nanoliter portion of the retained volume of liquid into a first container, the volume of the aspirated liquid being at least several times the volume of dispensed liquid.