How To Effectively Use Pippette Tubes?

Pipette tips are laboratory equipment that is used for dispensing measured amounts of liquids in different scientific and medical processes. For anyone who is in the lab, whether a novice or an expert, information on pipette tips is basic in ensuring the right measurements, minimizing contamination and enhancing the efficiency of the lab. In this article, we will give a brief description of the correct usage of pipettes as well as several suggestions that will help to enhance the quality of pipetting.  

Understanding Pipette Tips 

Pipette tips are tips with cylindrical cross-sectional shapes that are used to contain the liquid samples in transfer processes. They are usually made from plastic or glass and come in various sizes; microcentrifuge tubes, PCR tubes and conical tubes. These tubes are used together with pipettes which are very sensitive tools that are used in transferring liquids.  

Optimizing Pipette Tips for Increased Efficiency 

Pipette tips used in conjunction with pipettes should be handled in the following ways; increase precision in the measurements, reduce contamination and gain more efficiency. Some of the practices to consider are as follows:  

Choose the Right Pipette tip size. 

Pipette tips are also in microcentrifuge tubes of 0. 5 mL to 2. 0 mL and conical tubes ranging from 15 mL to 50 mL. The size of the tube required has to depend on the quantity of the liquid to be transported from one vessel to the other vessel. When the tube used is too big or too small, it may lead to wrong measurement or even the liquid cannot be sampled easily. 

• Microcentrifuge tubes: They are employed for volumes of liquids which are below 2ml and they are normally used with micropipettes. 
• Conical tubes: Best used for a large number of samples and are employed widely in cell culture, biochemistry and clinical laboratories. 

Proper Pipette Calibration 

The first activity that must be performed correctly is pipetting calibration which is used in handling liquids. Pipettes may be off by a few degrees after some time and this may result in inaccurate measurement of the volume of liquid. This has to be done from time to time so that the pipette should be able to pick up and deliver the correct volume of the liquid. 

• Frequency of calibration: Each pipette needs to be calibrated at least three to six months depending on the usage of the equipment. 
• Calibration checks: Some laboratories even have daily or weekly performance checks where water samples pre-weighed is used to check on the pipette. 

Correct Pipetting Technique 

How you handle tips determines the level of accuracy and precision in the results you obtain. Here are some tips that you need to consider to enhance your pipetting skills: 

• Pre-wet the tip: In case the last time when the sample is to be collected, it is preferred to wet the pipette tip by repeating the process of aspiration and dispensing at least once or twice. This eliminates evaporation and ensures that the right amount of the substance has been transferred from one container to the other. 
• Hold the pipette vertically: In this case, when transferring a liquid, ensure that the pipette is held vertically to get the right volume of the liquid. 

• Immerse the tip at the correct depth: The level of immersion should depend on the amount of volume that needs to be aspirated. In case the tip is placed too shallowly, then there is a possibility of the appearance of air bubbles and consequent distortion of measurement. If done too deep then the pipette tip gets contaminated with undesirable substances such as microorganisms. 
• Use slow and consistent pressure: To avoid splashing or formation of bubbles in the liquid while pipetting liquids, perform slow steady movements on the pipette plunger. 

Measures to be Adopted to Avoid the Pipette Tips to Contaminate the Solution 

This is always a challenge to get contamination in any laboratory especially when working with samples like DNA, RNA or proteins. Some of the methods that one can use to ensure that the sample and pipette tube are not contaminated include 

The proper techniques in pipetting. 

Where the biological samples or chemicals are prone to aerosol formation such as in the case of samples in liquid form, filtered pipette tips should be used. These tips are designed with filtering elements which helps to prevent aerosols and fluids from reaching the pipette and the sample to keep the pipette clean. 

Practice Aseptic Techniques  

If you are working in the laminar flow hood then you should always wear a mask and gloves and use gloves. Never bring the pipette tube in contact with your hand or gloves while using it because this will introduce contaminants into the solution. However, if it is necessary to manipulate the tube then it is done with sterile forceps only.

Change Pipette Tips after transferring from one sample to another 

 In general, do not pipet the sample to a new test tube or tube without first replacing the pipette tip. This is especially very important because even the traces of the previous sample may contaminate the current sample, especially in PCR.  

Use Sterile Pipette Tubes 

If pipette tubes are to be used for cell culture or microbiology work then these should be sterile. Some pipettes are purchased autoclaved if the tubes are to be used again then be sure to autoclave them or treat them with sterilizing solutions.  

Some Tips on Increasing the Efficiency of Liquids Transfer 

Pipetting is repetitive and even if there are slight differences in the procedure it takes a lot of time in the end. Here are some guidelines that can be followed when using pipette tips to increase the efficiency of the transfer of the liquid: 

Use Low-Retention Tips 

Low-retention pipette tips have a hydrophobic layer on the outer surface of the pipette tips so that the inside walls of the tip do not adhere to the liquid. This ensures that most of the liquid is agitated hence reducing sample wastage and at the same time enhancing accuracy. 

Do not work at a fast pace 

When transferring the solution from one tube to another, do this at a steady frequency. The rate at which aspirating or dispensing may occur may lead to inaccurate measurements, spills or even the inclusion of air bubbles. 

Avoid Over-Pipetting 

It is also important not to fill your pipette or pipette tube to its maximum level. If one transfers more volume than the one required, liquid spills over the pipette or outside the tube, the sample is contaminated or the sample is gone.  

Conclusion 

Pipette tips can be viewed as rather delicate tools, and the correct utilization of which directly depends upon how carefully some rules are complied with. It is equally important to choose the correct pipette and the type of tube that is to be used as well as the technique used in pipetting. Suppose you are to follow the tips that have been outlined in this article. In that case, you should expect to improve the accuracy of pipetting, minimize contamination cases and generally increase the efficiency of your laboratory.  

FAQs 

Q1: What precautions should be taken to prevent contamination of pipette tips? 

To reduce contamination issues, use Sterilized tips and filter pipette tips and practice the aseptic technique. The use of tips to transfer samples is recommended and it is recommended not to touch the sampling tube with hand or fingers. 

Q2: What is the importance of pre-wetting the pipette tip? 

Like with any other laboratory procedure, pre-wetting of the pipette tip helps to reduce the effects of evaporation and help in the delivery of liquids especially where a high degree of accuracy is required in experiments. 

Q3:  When should I calibrate my pipette?  

Pipettes should be calibrated at least once every three to six months of their usage depending on how frequently they are used. This is why the calibrations should be conducted from time to time to ensure that the measurements of liquids are accurate and consistent.