TM 5-6630-215-12e.Use ofFigure 2-2.Reading the MeniscusPipets and Cylinders.Rinse the pipet or cylinder twoor three times with the sample to be tested before filling.Use asafety pipet filler to draw the sample into the pipet.When filling apipet, keep the tip of the pipet below the surface of the sample asthe sample is drawn into the pipet, or you will lose the suction andpossibly introduce surface particles.(1) Serological Pipets.Serological pipets are long tubeswith a series of calibrated marks to indicate the volume of liquidthat will be delivered by the pipet.The calibrated marks may extendto the tip of the pipet may only be on the straight portion of thetube.Fill serological pipets to the zero mark and discharge thesample by allowing the sample to drain until the meniscus is levelwith the desired mark.If the serological pipet has calibrated marksextended to the tip of the pipet, the sample must be blown out of thetip for accurate sample measurements.(2) Transfer Pipets.Transfer pipets are long tubes with asingle ring to indicate the volume of liquid that will be deliveredwhen it is filled to the mark.To discharge the sample from a trans-fer pipet, hold the tip of the pipet at a slight angle against thecontainer wall and allow the sample or reagent solution to drain.Do not attempt to discharge that portion of the sample of reagentthat remains in the tip of the pipet after draining.Transfer pipetsare manufactured so that a reproducible amount of sample alwaysremains in the tip of the pipet.(3) The Rubber Bulb Pipet Filler.There are several types whichmay be used.The rubber bulb assembly can be used as illustrated(fig. 2-3).Insert the pipet into the sample; depress the bulb;restrict the intake end of the rubber tubing and release the bulb.Observe the pipet to ensure that the direction of suction isillustrated.2-5
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