In a laboratory environment, it is required to have a high degree of precision, a high degree of accuracy, and a low degree of contamination. Pipettes are particularly required in any experiment and assay that involves the transfer of fluids because they are used to measure out small volumes of fluids. However, one of the protocols that make these processes credible is the measures that involve changing the pipette tips after each use. This might look like a minor action, but it is one of the major and delicate actions that enable the accuracy of results and the avoidance of sample or experimental contamination amongst others.
Pipettes are used to dispense particular volumes of liquid but the accuracy has to be calibrated when the same tip is used. There may be some carry-over of the previous sample in the tip after the transfer and the next sample may be diluted. This can make it possible to obtain differences that are very far from the actual concentrations of the reagents or the samples required in an experiment.
That is why when using a pipette, scientists will always ensure that they change the pipette tip with a new one after every use due to the liquids that may be left on the tip which may lead to cross-contamination. This practice is important, especially during experiments especially when there is a need for a high degree of accuracy for instance in quantitative analysis or preparation of standard solutions.
Another kind of contamination is sample carryover in which some of the samples from the previous run adhere to the pipette tip and are transferred to the following sample. This is especially so where the experiment involves the setting up of different concentrations of reagents or working with sensitive biological specimens. When done, it results in a crossover that causes the samples to be contaminated to get the results.
This also helps in preventing cross-contamination because each sample is different from the other as well as the use of pipette tips. This is especially the case in a high-throughput system meaning a process or system that can process many tasks or data at a time, where many samples are run consecutively one after the other with high chances of contamination.
Contamination is one of the most important issues and a major concern of any laboratory. It occurs when there is interference by extraneous material, chemical, biological matter, or microorganisms in the sample that may influence the experiment. The presence of any level of contaminants in the samples will make it rather impossible to arrive at the correct conclusions.
Another aspect that could go wrong is using the same pipettes with different samples because they can introduce contaminants in the samples. This is especially so in experiments in biology for instance, where the contamination of the sample with other materials could complicate the experiment, if not ruin it completely especially when working with DNA, RNA, or proteins among others. For example in PCR assays used in DNA amplification, contamination from a previous sample can lead to either positive reactions when there are none or non-specific reactions.
Some laboratory activities need to be done aseptically. Tissue cultures, cell cultures, or microbiological tests must be done in an aseptic manner to exclude bacteria, viruses, or fungi.
The problem with using the same pipette tips, no matter how they may look, is that they introduce other impurities that were not in the sample. These interferences may either slow the growth of cells, alter the function of biological molecules or even produce erroneous results in microbiological assays. When using new tips for every sample, laboratories are also able to reduce sample contamination as much as possible to ensure that the experiments are very clean to obtain accurate results. However, one thing that needs to be looked at, about the use of disposable tips is its environmental effects.
In laboratory work one is always certain to make an error somewhere but the magnitude of the error is determined by the procedure followed in the experiment. Some of the mistakes that are often made include the following: failure to replace the pipette tips especially when transferring from one sample to the other. This little mistake can cause contamination, wrong measurement, and hence wrong results to be obtained, this shows why it is important to change the tips after every use.
Proper pipetting techniques are important in the laboratory to ensure that the experiments are repeatable and precise. In addition to changing pipette tip between samples, there are several other best practices that laboratory personnel should follow:
Laboratories should also make sure that personnel are trained from time to time to make sure that they know the right practices to follow and why it is necessary to change the pipette tips on every sample. This training, which should be conducted from time to time, aims at ensuring that you acquire adequate knowledge and skills to enhance the standard of the laboratory.
This is because using the same pipette tips to transfer solutions repeatedly compromises the validity of the results by causing cross-contamination that requires the replacement of the pipette tips to give accurate measurements.
Reuse of pipette tips leads to sample carryover, sample contamination, inaccurate results, and compromised sterility of the experiment thus making the experiment unreliable.
It is recommended that a new pipette tip should be used for each sample so that there is a steady flow of the experiment. It also reduces the probability of making an error and, thus, increases the reliability of various experiments’ outcomes.
