There are five commonly used classes of pipettes in pipette calibration, each with its own set of recommendations and standards for usage, testing, maintenance, and measurement. Pipettes are classified into five types: disposable/transfer, graduated/serological, single-channel, multichannel, and repeat pipettes. The way the equipment is handled, from the most simple transfer pipette dropper to the most complex repeat dispensing pipette, affects the accuracy of the test findings.
We take pleasure in providing our clients with compliance-oriented calibration services, but having in-depth knowledge of all the equipment we service is also part of our competence. This blog will outline the many types of pipettes and demonstrate how to use them to guarantee that your tests get the most exact findings with the least margin of error:
This is the most basic pipette; it is not a complex piece of laboratory equipment and should only be used for crude measurements. When utilizing a disposable pipette, it is critical to use a conventional pipetting method. Aspirate liquid at a 90-degree angle, dispense at a 45-degree angle, and tap off to ensure all liquid is delivered.
The ultimate volume is determined while using this sort of pipette by calculating the difference in the liquid level before and after the liquid is administered, much like a burette. The typical method for using a graduated pipette is as follows:
- Don't let the pipette contact the bottom of the fluid.
- Squeeze the bulb and attach it to the pipette's tip.
- To regulate the volume of aspiration, place your finger on top of the pipette.
- To ensure precise measurement, subtract the required quantity into a separate beaker while remaining eye level.
- Measure the solution from the bottom of the meniscus, the crescent-shaped liquid surface visible in the pipette.
- Subtract the required volume from the beginning volume to obtain the volume to which the desired quantity must be released.
A single-channel pipette is a non-disposable tool, often of the air-displacement variety, that gives reliable measurement results with the use of a single disposable tip. Single-channel pipetting is commonly associated with two techniques:
Forward Technique: This is the intended purpose and the most commonly used pipette measuring technique. To employ this approach, first press the plunger to stop and gently submerge the pipette tip in the liquid, then aspirate your measured volume by slowly releasing the plunger to avoid bubbles. Place the tip against the receptacle's side, and then carefully press the plunger through the first stop to the final blowout position while "touching off" the last drop from the tip.
Reverse Technique: When working with viscous solutions or solutions prone to bubbles, we have the option of using a reverse pipetting approach to reduce interference from air bubbles. To employ this approach, press the plunger all the way down to the third stop position (all the way down), gently submerge it into the liquid, and then slowly return the plunger to the top to aspirate the liquid into the tip. Place the pipette tip against the receptacle's wall and press the plunger to the first stop, then withdraw the tip from the receptacle. You now have a sample of liquid in your tip that is not part of the measurement. You may then repeat the aspiration procedure and continue.
A multichannel pipette uses the same technology and approach as a single-channel pipette. However, it accepts more than one tip at a time. Because the liquid is aspirated from the same well into several channels at the same time, you must guarantee that the aspirated liquid levels are similar before the liquid may be distributed into your tubes or plate wells. The approach is identical to the single channel technique; however, the result is vastly different:
- Install the appropriate tips for each channel and adjust the volume to your liking.
- Hold the pipette vertically, and depress the plunger to the first stop.
- Immerse the plunger tip in the liquid, and then return it to its resting position.
- Place the tip at a 45-degree angle toward the wall of the vessel that will receive the liquid.
- Depress the plunger to the first stop, pause one second, and then expel all the liquid while "touching off" the final drop.
- Remove the tip from the liquid and return the plunger to the resting position.
Repeat Pipette Dispenser
A technician may use this pipette to set and dispense a specified volume into various receptacles without having to aspirate in between dispenses. This capacity for multi-dispensing saves time and labor. The repeat pipette dispenser is not like a traditional pipette. The distinction is between a filling and dispensing lever and a plunger. Follow these steps to properly utilize a repeating pipette:
- Slide the filling lever all the way down.
- Raise the locking clamp to the top.
- Close the lever after inserting the syringe-type tip into the barrel until it snaps into place.
- Immerse the tip at a 90-degree angle in the liquid.
- Slide the filling lever slowly upward to completely fill the tip.
- Discard the liquid from the initial dispense to prime the tip.
- The repeat pipette is now operational.
Before you begin your liquid measurement and pipetting approach, you should examine the sort of test you're performing and select which pipette type is the best fit. Using the improper instrument or even the correct instrument incorrectly can have a big influence on your results. Accuracy and repeatability are two of the most crucial features of pipette testing. Nevertheless, professionals cannot anticipate exact findings unless they have expert knowledge of how to handle all lab equipment.