Using a Micropipette - University of Leicester

gilsu north in micropipette Azhar one of the most commonly used instruments in a molecular biology laboratory they're used in conjunction with plastic disposable pipette tips to measure or transfer small amounts of liquids usually from 0.2 microliters to 1000 microliters or one milliliter different per pets work across different ranges of volumes and are named by the maximum volume they pipette the different Pathet suck very similar so they're labeled on the top of each push button with a capital P followed by a number which indicates the maximum volume for that particular pipette a p2 pipettes between 0.2 and 2 microliters a p20 per pets between 2 and 20 microliters a p2 hundred per pets between 20 and 200 microliters and ap1000 per pets between 100 and 1000 microliters a pipette is an expensive precision instrument improper use will damage the pipette so correct use is essential you should never use a pipette to measure volumes outside of its range for example using a pea 202 pipette to lower volumes such as 10 microliters or to higher volumes such as 250 microliters will result in inaccurate volume measurements and will damage the internal mechanism of the pipette each pipette has a vertical row of three numbers visible in the body of the instrument to set the volume you can use either the thumb wheel or on newer models the push-button this will cause the three number dials in the body of the pipette to rotate and change the volume of liquid that will be taken up however the dial numbers indicate different volumes depending on which pipette is used for example these three per pets have been set to read the same numbers on the dial one five two four the p2 this means that the pipette is set to a volume of 1.5 to microliters the bottom two dolls are in red indicating five tenths and two hundredths of a microliter for the p20 this means that the pipette is set to a volume of fifteen point two microliters the red bottom dollar owes two tenths of a microliter with the p200 the same visual setting means that the pipette is set to a volume of 152 microliters this p1000 is set to 0-5 two which indicates a volume of five hundred and twenty microliters a setting of 100 indicates the maximum volume for this per pet which is 1000 microliters the uppermost number is in red which for this per pet indicates the number of milliliters once you've set the volume you need attach the appropriate pipette tip to the end of the pipette P 20 and P 200 per pets use the same yellow tips P 1000 per pets use larger blue tips another type of tip called a filter tip is often used in the laboratory the sterile filter within each tip can help to prevent contamination hold the pipette with one hand with the narrow side resting in the palm of the hand add the pipette tip by gently but firmly pushing the pipette into the pipette tip which is held in a tip box you may need a little practice to learn to apply the right amount of pressure to give a good airtight seal between the tip and the pipette liquid is drawn in and expelled using the pipette spartan gently apply pressure to the button with your thumb until you feel a natural stop this is called the first stop the distance you need to push the push button down will vary depending on the volume you require a p20 set to 2 microliters will require less push-button movement than a p20 set to 20 microliters so to use the pipette push the button down to the first stop then keeping the push button at this level place the pipette tip about two millimeters into the liquid you wish to draw up release the push button by slowly allowing it to return to its original position pause for a second to make sure all the required volume of liquid has been taken up into the tip this is especially important when using more viscous liquids which take longer to draw up withdraw the pipette tip from the liquid and place it inside the recipient container slowly push down on the push button this will release the liquid in the pipette tip into the tube this time pushed beyond the first stop this ensure that any residual liquid is expelled from the pipette tip fully withdraw the pipette tip from the liquid before you release the push-button so to recap push down the push button until you feel some resistance place the pipette into the liquid and slowly release the push button release the liquid from the pipette by pushing past the first stop to fully expel the liquid from the pipette tip into the recipient container withdraw the pipette from the container before you release the button for very small volumes the aspirated liquid can hang in a drop from the end of the tip and may not be transferred to the tube at all so you should touch the tip to the inside wall of the recipient container whilst expelling the liquid once you've aspirated the liquid release the pipette tip from the pipette by pressing down on the tip ejector this is the small white button at the top of the main body of the pipette be sure that the attached pipette tip is inside the appropriate waste container before pressing the tip ejector a new clean pipette tip should be used with each new liquid or if the tip touches any surface or any liquid other than one your pathetic if in doubt change the tip do not use a pipette without a tip attached liquid should never enter the body of the pipette it will cause the pathetic corrode and will be a major source of contamination between liquids and experiments do not use a pipette past its volume limits this causes pipetting inaccuracies and also damages the pipette if you're having trouble attaching a tip to your pipette don't repeatedly Jam the pipette into a tip this can damage the pipette and if the tip doesn't stay on the end of the pipette simply repeat the procedure with a new tip when pushing down the push-button to take up a set volume of liquid don't push past the first stop if you push past the first stop the volume you then take-up will be too large when taking up liquids don't simply let go of the push button the liquid can be sprayed around the inside walls of the tip and up into the pipette body causing inaccurate volume dispensing and pipette contamination make sure you release the push button in a controlled manner if you don't pause after you release the push button there won't be enough time for the correct volume to be taken into the tip air will be taken in instead also when you're withdrawing a large volume from a narrow container make sure the tip stays below the surface whenever you have liquid in a pipette tip don't play the pipette down liquid can get into the body of the pipette which causes cross-contamination pipette damaged and inaccurate per petting and finally remember when per petting small volumes touch the pipette tip to the side of the tube to ensure the liquid is released into the recipient container

Channel: University of Leicester

Views: 751,208

Rating: 4.9322963 out of 5

Keywords: Using a Micropipette, Micropipette Technique, Micropipette, GENIE, University of Leicester, Biological Science, Gilson Micropipette, Raymond Dalgleish, Nicola Suter-Giorgini, Cas Kramer

Id: uEy_NGDfo_8

Length: 8min 49sec (529 seconds)

Published: Thu Jun 25 2009