Pre-wetting is one of the fundamental techniques in laboratories that enables the enhancement of the liquid transfer process. Pre-wetting is the act of wetting the interior of the pipette tip before using it to dispense the liquid you are measuring so that the liquid will behave in the manner you expect it to because it won’t stick to the walls of the pipette tip, especially when you are measuring small volumes or viscous liquids in this article, we will explain the importance of pre-wetting pipette tips, how to pre-wet ti, ps and how to optimize your pipetting plan.
These procedures include pipetting, whereby the pipette tip is moistened by drawing the liquid into the pipette and then dispensing it. This small change can go a long way in improving the level of accuracy in pipetting, especially where high levels of accuracy are needed. The first objective of pre-wetting is to create the same conditions in the tip as much as possible to the conditions of the experiment. This is particularly so when the pipette tip is dry; the first measurement may be inaccurate since the liquid tends to stick to the inner walls of the tip. This is minimized by pre-wetting as the tip is ready for the liquid and therefore, precise outcomes are obtained.
The following are some of the benefits associated with pre-wetting a pipette tip, which are very important in making sure that your experiments are valid. First, it reduces the surface area available to adhere to the pipette tip's inner wall, which is important when handling small volumes. It also improves the reproducibility of the measurements in a manner that makes each aspiration and dispensing cycle reproducible. In addition, pre-wetting helps to minimize the impact of air bubbles, which is one of the causes of variation in the volume of the liquid dispensed. In conclusion, pre-wetting is a simple but effective technique for enhancing your pipetting abilities.
The following are the steps that need to be followed to achieve proper pre-wetting of the pipette tip:
However, their application is helpful in many cases, and they are most advantageous when used in specific liquids and under specific experimental conditions. Pre-wetting is crucial, especially when dealing with highly viscous solutions like glycerol or some oil, because these solutions stick to the walls of a dry pipette tip. It is also important when working with flammable liquids since they tend to evaporate, thus causing difficulties in the measurements. Moreover, pre-wetting is recommended when small portions are applied, and even the remaining liquid on the sample's surface will influence the outcome.
However, as is clear from the description above, pre-wetting can be done wrongly if some measures are not taken. Another mistake is that too much liquid is aspirated during the pre-wetting step, which results in overfilling and spilling. The correct amount of liquid to aspirate should fill the tip to the top, not the filter or the pipette’s body. The other mistake is not repeating the pre-wetting process if required, especially when handling viscous or volatile liquids. Failure to do so leads to poor measurement, which is particularly dangerous in applications where precision is crucial. Lastly, do not use the same pipette tip for different samples if the pipette tip has not been pre-wetted appropriately since this will lead to contamination.
The following are some tips to enhance the accuracy of pipetting.
Some tips include ensuring the pipetting angle is constant and the pipette tip is dipped into the liquid to the right level. This practice also minimizes the chances of an air bubble getting into the tip, distorting the measurement. It is also crucial to select the right pipette tip according to one's needs and to make sure that the tip fits the pipette and is suitable for it. It is also important to service and calibrate your pipettes often to ensure that they do not drift off and give inaccurate volumes as may be required. Last, always pipette gently and steadily; do not pipette fast or jerk the pipette since this will lead to inaccuracy.
One of the most basic yet rather efficient methods that can enhance the reliability of pipetting is the pre-wetting of the pipette tips. Proper conditioning of the pipette tip to the liquid being measured reduces the chances of getting inaccurate results due to liquid retention, trapped air bubbles, and other related issues. Therefore, by including pre-wetting in your pipetting process and observing proper pipette handling, you will get more consistent and accurate results in your laboratory experiments.
Pre-wetting is crucial to low retention and filtered tips while using small volumes or highly viscous liquids, but it is useful with any type of tip.
Normally, pre-wetting is done once or twice, but it may be necessary to pre-wet several times for highly viscous or volatile fluids.
Yes, pre-wetting helps reduce sample loss by reducing the surface area for the liquid to adhere to the walls of the pipette tip, hence improving the accuracy of the measurements.
