Table of Contents
Dispose of the chemicals in proper wast containers and wash the materials. How can you draw small volumes of liquids into a pipette safely? Draw the chemicals with a pipette bulb. A small container is the safest to use and easy to control.
How do you make a liquid into a pipette?
Rinse the pipet two or three times with the liquid you wish to transfer. Do this by drawing a small amount of liquid into the pipet, turning the pipet horizontally and rotating it so that the liquid contacts the entire inside surface of the pipet. Let the liquid drain into a waste container.
How do you draw solutions into a pipette?
Draw a small amount of the solution you wish to pipet into the pipet. Tilt and roll the pipet so that the solution has contact with all the inside surfaces. Discard the solution from the rinses. Repeat this rinse at least once more.
Do not allow the solution to be drawn up into the pipettor This will result in chemicals getting into the top of the pipet where you must put your finger?
Do not ever use your mouth to pull the liquid into a pipet. This will result in chemicals getting on top of the pipet where you must put your finger. Do not insert the pipet into the hole in the bulb. You might break the pipet and cut yourself while trying to insert it.
What device is used to draw liquid into a pipette?
Pipette-aides or pipettors are suction devices that are used to either suck liquids into or expel liquids out of pipettes. For some types of measurements it may be necessary to expel, or blow-out, the total liquid volume from the pipette using the pipette-aid.
How a solution is drawn into a pipette by using a pipette filler?
Insert the tip of the pipette into the liquid to be dispensed. Siphon liquid into the pipette to the desired level by squeezing valve “S” on the bottom of the pipette filler. This uses the vacuum created in the bulb to draw liquid into the pipette. Be careful not to draw liquid into the pipette filler.
Which is the correct method for drawing liquid into a pipette?
Set the volume on the pipette. Depress the plunger. Immerse the tip to the correct depth, which can vary by the pipette and tip, and smoothly let the plunger go to its resting position. Wait about one second for the liquid to flow into the tip.
When liquid is drawn into a volumetric pipet Why should the liquid level not be allowed to fall below the calibration mark?
Remember: When using a buret do not allow the liquid level to fall below the 50.00 mL calibration mark as the volume in the tip of the buret is not known and will introduce error into the experiment.
When drawing liquid into a volumetric pipet where should you aim the tip?
(NEVER pipet directly from a reagent bottle or volumetric flask.) Place the tip of the pipet below the liquid’s surface. Using a bulb or pump, draw the liquid into the pipet. Draw slightly more liquid than needed, but DO NOT allow the liquid to enter the bulb.
Why do you need to condition the volumetric pipette with each solution?
If droplets form on the walls, wash the inside with a soap solution, and rinse with distilled or deionized water. Repeat the cleanliness test. Just before use, a buret should be “conditioned” to ensure that any water adhering to the inside walls is removed.
Do you need to remove the last drop of the solution in the pipette?
The last drop inside a pipette is not blown out because a small drop of liquid stays in the pipette on account of surface tension. Secondly, pipettes are made in such a way that the experimental value does not get affected by this drop. If it is blown off, you will get a wrong value.
When drawing liquid into a micropipette at what point should you push the plunger to the first stop?
Press the plunger down until the first stop – be careful to not go past the first stop! Depress the plunger BEFORE you put your pipette into the solution – otherwise bubbles can be created, introducing air that can cause contamination and other problems.
Why should a pipette always be rinsed first with the liquid to be used?
It’s an analytical technique that can be used to find the concentration of a solution (the amount of a solute dissolved in it). Prior to this, the pipette should have been rinsed with distilled water, followed by the solution it is to be filled with, again to avoid contamination.
Should the little liquid on the tip of the pipette be squeezed out?
A volumetric pipet should not be “blown out” to eject all liquid at the tip because volumetric pipets are calibrated in a manner that takes into account the solution which remains at the tip due to surface tension. Do it gently so that the meniscus drops slowly to the calibration mark.
What is the use of volumetric flask?
A volumetric flask (measuring flask or graduated flask) is a piece of laboratory apparatus, a type of laboratory flask, calibrated to contain a precise volume at a certain temperature. Volumetric flasks are used for precise dilutions and preparation of standard solutions.
How do micropipettes work?
The air displacement micropipettes work on the common air displacement principle. A plunger is depressed by the thumb and as it is released, liquid is drawn into a disposable tip. When the plunger is pressed again, the liquid is dispensed.
What is the use of dropper in laboratory?
An eye dropper, also known as a Pasteur pipette, or dropper, is a device used to transfer small quantities of liquids. They are used in the laboratory and also to dispense small amounts of liquid medicines.
Why should pipette be drained in a vertical position?
The pipette should be held vertically during aspiration. On aspiration of the liquid the hydrostatic pressure of the liquid column in the tip falls as the angle of inclination of the pipette increases.
What is the best way to remove drops of solution adhering to the tip of a pipette?
Remove the tip by touching off the liquid droplet on the surface of the liquid in the container. Recommended when dispensing less than 1µL as a neat transfer. Touching the droplet to the liquid draws the small droplet out of the pipette tip which ensures accurate delivery.
How does a volumetric pipette work?
A volumetric (Transfer) pipet delivers its marked capacity in one delivery (capacity is printed on the bulb). These pipets are filled to a level above the capacity mark and then water is released until the meniscus is aligned with the zero graduation. The pipet is then completely emptied into the receiving vessel.
