Patent ID: 8414778

Claim:
A filtration method comprising: a liquid introducing step to introduce a liquid into a filter-incorporated tip through a guide opening portion thereof, wherein the filter-incorporated tip has a nozzle-tipped container and a filter, the nozzle-tipped container has a guide opening portion that can be directly or indirectly fitted to an air nozzle capable of ejecting a gas and a front nozzle portion capable of delivering the liquid by the ejection of the gas from the air nozzle, and the filter is locked in the nozzle-tipped container to partition the interior of the nozzle-tipped container into the guide opening portion side and the front nozzle portion side and can temporarily hold the liquid and isolate a predetermined substance as the liquid passes through the filter, when the nozzle-tipped container is coupled to the air nozzle on the guide opening portion side; a coupling step to directly or indirectly couple the filter-incorporated tip containing the liquid to the air nozzle; a pressure application step to eject the gas from the air nozzle into the coupled filter-incorporated tip; and a preprocessing step to process the liquid using a pipette tip fitted to the air nozzle before the liquid introducing step, the air nozzle being capable of performing a suction of gas in addition to the ejection; wherein the liquid introducing step comprises introducing the liquid into the filter-incorporated tip using the pipette tip; and wherein the coupling step comprises removing the pipette tip from the air nozzle and then directly or indirectly coupling the filter-incorporated tip to the air nozzle.