Pipette tips should be chosen based on their function and quality. Two main factors affect the quality of the tips. The first factor is the polypropylene blend. High-quality tips are produced by virgin polypropylene, free from plastic and metal additives that can contaminate the samples. When buying colored tips, make sure to check whether the tips contain metal additives or not.
The second factor that influences the quality is the injection molding machine. Minimal variations, either inter-batch or intra-batch, like straightness differences, molding flash, or streaking, can adversely affect the precision of the results. These imperfections cannot be seen with the naked eye. Hence, you must avoid buying substandard tips to minimize the risks of inaccurate results.
When choosing the pipette tips, the options are endless. There are non-sterile and sterile tips, filter and non-filter tips, long, short, and low-retention tips, and so much more. To help you choose the best pipette tip according to your application, here’s a simple breakdown:
Sterile or Non-Sterile
The applications where sterility is essential must consider the use of sterile tips. However, you can also get non-sterile tips and autoclave them yourself. This will be a great way to save money. One thing you need to ensure is that the non-sterile tips must be autoclavable. You should also make sure of the following essential aspects:
- Quality Control
Tips coming straight from manufacturers are sterilized and are checked regularly for quality. On the contrary, labs do not perform tests to check the effectiveness of the autoclaving process. This negligence can often lead to contaminated samples.
- RNase and DNase
If you are autoclaving the tips yourself, you must know that albeit free from living organisms, yet not necessarily free from DNase and RNase. When performing sensitive tests, the better approach is to go for sterile tips from a reliable resource that can guarantee DNase and RNase-free tips.
When liquids are aspirated, aerosols are generated within pipette tips. These aerosols can contaminate the pipette and the upcoming samples if you do not use filter tips. Filter tips are an essential requirement for sensitive testing.
For instance, when performing PCR testing for COVID-19 or other samples, there is an excellent probability of cross-contamination by aerosols in the pipette. This can result in false-positive results since even the most negligible quantities of DNA from a prior sample have the potential to amplify.
It is essential to use filter tips when handling liquids that can damage the pipette. For instance, you must use filter tips when testing radio-labeled or corrosive samples for your safety as well as the pipette. Here are some liquids that must be handled with filter tips to avoid pipette contamination.
- Infectious samples
- DNA or RNA samples
- Strong bases and acids
- Viscous, volatile, or corrosive samples
- Radio-Labeled samples
Filter tips are also handy to train new lab technicians. If you spend a little extra money on filter tips, it will save you in the long run. The new technicians will get some time to get accustomed to the instruments, and you will also limit the possibility of pipette contamination or damage. The chances of liquids entering the bottom end of the pipette will be significantly reduced.
It’s a common accident where a technician has cross-contaminated by putting the pipette shaft into a tube for standard tips to reach the bottom part. In order to eliminate the risk, many manufacturers offer an extended length of pipette tips. This extension is suitable for labware such as deep-well blocks or microcentrifuge tubes.
Short tips offer a couple of benefits. They support the targeting of small wells. For instance, when manually pipetting into a well plate with a multichannel pipe. Another benefit is that they can improve the ergonomics by allowing the user to pipette near the bench. This can considerably reduce the strain in the user’s arm.
Wide Bore Tips
Forcing fragile narrow samples through the narrow orifice of conventional tips can cause them to damage. Hence, you must use wide bore tips when transferring cellular samples, for example, fragile cell lines or other viscous materials. A wider orifice prevents cell shearing and also reduces the resistance in the flow of liquids.