Techniques on the Use of a Pipette
TLDRThis informative video tutorial demonstrates the proper use of a 10-mL volumetric pipette to accurately deliver 10.00 mL of Solution A into an Erlenmeyer flask. It emphasizes the importance of pipette inspection, acclimatization, and correct technique to avoid contamination and ensure precise measurement. The steps are clearly outlined, from filling and rinsing the pipette to delivering the solution, with tips on maintaining the meniscus level at the calibration mark and avoiding drips post-transfer.
Takeaways
- 🔍 Always inspect the pipette for chips and a smooth, flat top end to ensure proper functioning.
- 💧 Acclimatize the pipette by rinsing it with the solution to be used, avoiding contamination.
- 🥼 Use a clean, dry beaker to pour a small quantity of solution for pipetting, not directly from the storage flask.
- 📊 Compare solution depths in beakers of different sizes; a smaller depth facilitates pipetting.
- 💉 Use a rubber bulb to draw up the solution for pipette acclimatization, keeping the tip submerged.
- 🖐 Hold the pipette with your left hand, using your right hand to depress the bulb if you're right-handed.
- 🚫 Ensure the solution level rises up the pipette without draining back into the beaker during acclimatization.
- 🌡️ For accurate measurement, fill the pipette past the calibration mark, wipe off any external liquid, and align it with your eye level.
- 🔄 Release the solution slowly, stopping when the meniscus bottom aligns with the calibration mark, ensuring no hanging drop at the tip.
- 🥣 Transfer the solution into an Erlenmeyer flask by touching the pipette tip to the flask wall and waiting 10 seconds before removing.
- 🧪 Do not blow out the pipette after transferring; leave any remaining solution in the tip to avoid altering the delivered volume.
Q & A
Why is it important to inspect the pipette before use?
-Inspecting the pipette ensures that the tip is not chipped and the top end is smooth and flat, which are crucial for accurate pipetting. A damaged pipette can lead to difficulties in delivering the correct volume of solution.
What does acclimatizing a pipette entail?
-Acclimatizing a pipette involves rinsing it with the solution to be used, ensuring that any residual contaminants are removed and the pipette is ready for accurate measurement and transfer of the solution.
Why should you not pipet solution directly from the storage flask?
-Pipetting directly from the storage flask can contaminate the solution. It's best to transfer a small quantity into a clean and dry beaker to maintain the integrity of the solution and prevent any potential cross-contamination.
How does the depth of the solution in a beaker affect pipetting?
-The depth of the solution affects pipetting ease and accuracy. A beaker with a smaller volume of solution has a greater depth, making it easier to pipette without introducing air or sucking up too much liquid.
What is the correct hand position for using a pipette if you are right-handed?
-If you are right-handed, you should depress the pipette bulb with your right hand and hold the pipette in your left hand, keeping your index finger near the top to easily cover the pipette when removing the bulb.
How do you properly fill a pipette for acclimatization?
-To fill a pipette for acclimatization, use a rubber bulb to draw up the solution, ensuring the tip remains below the surface of the liquid to avoid air intake, and fill to about one-third to one-half of the bulb's volume.
What should you do after drawing up the solution for acclimatization?
-After drawing up the solution, remove the bulb, tilt the pipette horizontally to rinse the inner walls, and ensure the solution slides past the calibration mark and rotates to touch all inner surfaces. Then, drain the solution completely and dry the pipette top before repeating this process three times.
How do you accurately deliver 10.00 mL of solution using a volumetric pipette?
-To deliver 10.00 mL accurately, fill the pipette past the calibration mark, cover the top with your index finger, and ensure no liquid is on the outside. Adjust your hand position for stability, bring the calibration mark to eye level, and slowly release pressure until the meniscus aligns with the mark. Confirm there's no hanging drop, and then deliver the solution into the receiving container.
What is the proper way to transfer the solution into an Erlenmeyer flask?
-Transfer the solution by bringing the pipette to the Erlenmeyer flask, releasing the pressure on your index finger, and allowing the solution to drain into the flask with the tip touching the wall. After draining, wait 10 seconds before removing the pipette to ensure all the liquid has been transferred.
Why should you not blow out the remaining solution in the pipette tip after transferring?
-Blowing out the remaining solution can alter the accuracy of the transferred volume. The pipette is calibrated to deliver a precise amount, and the remaining drop at the tip is accounted for in the calibration process.
Outlines
🧪 Introduction to Pipetting Techniques
This section introduces the viewer to the proper techniques for using a 10-mL volumetric pipette to deliver 10.00 mL of solution into an Erlenmeyer flask. It emphasizes the importance of inspecting the pipette for damage, acclimatizing the pipette by rinsing it with the solution to be used, and ensuring the solution is transferred from an appropriate beaker to avoid contamination. The process of filling the pipette for acclimatization using a rubber bulb is explained, detailing the correct hand positions and methods to avoid drawing air into the pipette or contaminating the solution. It also covers the importance of rinsing the inner walls of the pipette with the solution, draining it completely, and repeating the acclimatization process three times.
Mindmap
Keywords
💡Pipette
💡Acclimatize
💡Volumetric Pipette
💡Calibration Mark
💡Meniscus
💡Erlenmeyer Flask
💡Contamination
💡Rubber Bulb
💡Beaker
💡Drain
Highlights
Introduction to pipetting techniques for delivering 10.00 mL of solution using a 10-mL volumetric pipette.
Importance of inspecting the pipette tip and top end for chips and smoothness.
Procedure for acclimatizing the pipette by rinsing it with the solution to be used.
Highlighting the importance of not pipetting directly from the storage flask to prevent contamination.
Comparison between using a 50-mL and a 250-mL beaker for pipetting ease.
Using a rubber bulb for filling the pipette and techniques for right-handed individuals.
Ensuring the pipette tip stays below the liquid surface to avoid air intake.
Proper technique for acclimatizing the pipette with a small amount of solution.
Technique to rinse the inner walls of the pipette, ensuring contact with the calibration mark.
Repeating the acclimatization process three times for thorough preparation.
Instructions for filling the pipette past the calibration mark and controlling the solution level.
Correct posture for viewing the meniscus at eye level and adjusting to the calibration mark.
Ensuring there is no hanging drop at the pipette tip before delivery.
Proper technique for delivering the solution into an Erlenmeyer flask.
Waiting 10 seconds after solution delivery before removing the pipette.
Final note on the residual solution in the pipette tip after delivery.
Transcripts
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