Now that you know when to choose each type of tip, we need to address tip quality and fit. Low quality or poorly fitting tips can negatively impact the reproducibility of your results. This means that you will need to repeat experiments, wasting valuable time and money. On top of that, repeating experiments means even more pipetting, which increases the strain on your arm, wrist and fingers – especially if you use poorly fitting tips that require high attachment and ejection forces – and can ultimately lead to repetitive strain injuries.
2. How to assess tip quality
The first factor influencing the quality of tips is the polypropylene blend. High quality tips are made from virgin polypropylene, which is free from plastic and/or metal additives that could contaminate your samples. Checking that a manufacturer doesn't use metal additives is especially important when buying colored tips, as metal additives can often be found in dyes.
The second factor influencing quality is the injection molding machine. The slightest batch-to-batch or within batch variations – such as differences in straightness, molding flash or streaking – negatively impact the accuracy and precision of your results. These irregularities often can't be seen by the naked eye, so it is better to avoid buying the cheapest tips on the market, to reduce the risk of inaccurate and imprecise results.
2. How to find a properly fitting tip
Tip shapes are not universal, so not every tip will fit your pipette. Ideally, you should only use the tips recommended by your pipette manufacturer. If you use tips that haven't been tested and validated by your manufacturer, you should always gravimetrically test their performance to ensure that they produce reliable results.
3 Conclusion
Buying high quality, properly fitting tips might seem more expensive at first glance, but will save you a lot of time, money and health issues. However, the question of whether you can work with non-sterile standard tips, or whether you need to invest in tips with features such as heightened hydrophobic properties or wider tip orifices, depends on your requirements. Make sure to answer this question every time you start a new application by following our hints above, so that your tips will never compromise your lab work again.
