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RULE OF THUMB: Always select the SMALLEST size pipet that will handle the volume you wish to move to achieve the greatest accuracy. Accuracy decreases as you use unnecessarily large pipets for small volumes.
278 Micropipette Tutorial From the Office of Science Lab Technical Assistant CCC 278 This is a Micropipette it is used to accurately transfer small quantities of liquid On this model the desired volume can be adjusted within the range of microliters (μL) Some Micropipettes have preset volumes and cannot be adjusted This pipette will only deliver 200μL How does it work? It works much like a syringe that would deliver an injection 278 Inside there is a spring loaded piston that moves up and down 278 278 The plunger has two stops: - at the First Stop the piston moves through the volume that is set on the pipette (In this case 278μL) 278μL 278 - The second stop is extra travel used for certain circumstances like evacuating the tip, or drawing up more than the volume indicated on the pipette 278μL 278 - Extra volume (? μL) 278 278 - Find all three positions 278 Proper Use RULE OF THUMB: Always select the SMALLEST size pipet that will handle the volume you wish to move to achieve the greatest accuracy Accuracy decreases as you use unnecessarily large pipets for small volumes • P20 pipet: Maximum volume 20ul Accurate between 2ul and 20ul • P100 pipet: Maximum volume 100ul Accurate between 10ul and 100ul Deliver 15ul which pipet? 278 Setting Volume Set the correct volume on your micropipette by turning the adjustment knob (typically the plunger button) clockwise to increase volume or counterclockwise to decrease volume 78 This2pipette’s range is 200-1000 μL and is set to deliver 278μL NEVER exceed the upper or lower limits of the pipette Setting Volume 278 Settings can vary between models and manufacturer s This pipette’s range is 20-100 μL and is set to deliver 27.8μL However you might see the following readings for this exact setting on different pipettes: 278 27 278 The first two make the decimal places obvious, while the last one implies the tenths place if you know the range Attaching tip 278 Press the pipette into the tip firmly to create an airtight seal Attaining a Sample STEP ONE – press 278 HOLD plunger to first stop and hold Attaining a Sample STEP TWO – Insert tip into 278 HOLD KEEP the pipette VERTICAL at all times sample only far enough to ensure it stays submerged but not to the bottom where it will get blocked Attaining a Sample STEP THREE – Allow 278 plunger to return to the home position SLOWLY so you don’t draw in air bubbles, or splash sample up into tip or the pipette itself KEEP the pipette VERTICAL at all times Attaining a Sample Removed tip from sample before the plunger was all the way home CORRECT Likely allowed the plunger to move to home too quickly Delivering the SampleSTEP FOUR – insert tip 278 into the area you wish to deliver your sample (in this case a gel) KEEP the pipette VERTICAL at all times Delivering the SampleSTEP FIVE – depress the 278 HOLD KEEP the pipette VERTICAL at all times plunger slowly to the first stop, then continue to the second stop, this will evacuate the entire contents of the tip And HOLD Delivering the SampleSTEP SIX – While still 278 HOLD KEEP the pipette VERTICAL at all times holding the plunger at the second stop Withdraw the tip from the well Delivering the SampleSTEP SEVEN – Allow the 278 plunger to return home KEEP the pipette VERTICAL at all times Discarding the Tip STEP EIGHT – Place tip into the opening of the waste container, then depress the tip ejector Tip Ejector 278 Be sure to use a new tip each time WASTE KEEP the pipette VERTICAL at all times Things to AVOID !! 278 Never use a pipette in anything but a vertical orientation 278 Things to AVOID !! Never use a pipette without a tip Small Volumes Technique With small volumes, especially the 1-10ul range, you must keep track of the droplets you pipet •Carefully expel the liquid droplet on the side wall of the tube so that you can see it, drawing the tip away/out carefully BEFORE releasing the plunger •If adding to a larger volume, flush the tip with the solvent liquid after expelling the droplet to make sure you get all the delivery liquid Reverse pipetting vs forward pipetting Reverse pipetting is recommended for solutions with a high viscosity or a tendency to foam Press the plunger to the second stop Dip the tip into the solution, and slowly release the plunger fill the tip with a volume that is larger than the set volume Dispense the liquid into the receiving vessel by pressing the plunger to the first stop this volume is equal to the set volume Hold the button in this position The liquid remaining in the tip can be pipetted back into the original solution or disposed together with the tip Release the plunger to the ready position Pipetting volatile compounds Technique: use the forward pipetting technique 1-2: Calibrate the pipette with the volatile compound aspirate and dispense the liquid a few times keeping the tip in the liquid By doing so, the air inside the pipette will be saturated with vapor of the volatile compound 3-6: Pipette rapidly to avoid evaporation using the forward pipetting technique ... evacuate the entire contents of the tip And HOLD Delivering the SampleSTEP SIX – While still 278 HOLD KEEP the pipette VERTICAL at all times holding the plunger at the second stop Withdraw the tip from. .. Press the plunger to the second stop Dip the tip into the solution, and slowly release the plunger fill the tip with a volume that is larger than the set volume Dispense the liquid into the receiving... volumes, especially the 1-10ul range, you must keep track of the droplets you pipet •Carefully expel the liquid droplet on the side wall of the tube so that you can see it, drawing the tip away/out