Pipette use: pipetting tips for special samples

In most cases, the pipetting objects are all aqueous solutions, but it is inevitable to encounter special samples such as highly volatile samples, high viscosity samples, high density samples or very warm samples. . If you need to transfer these special samples often, Leber still recommends that you buy a Pipette with an external piston principle (such as the German IKA pipette). Although the cost of consumables is a bit high, the pipetting accuracy is guaranteed. If you only transfer special samples occasionally, and the financial resources are limited, Then please take a look at this article, it will help you to improve the accuracy of pipetting as much as possible (it can only be said to be helpful, after all, than the special external piston pipette). Below are the pipetting techniques for different samples.

1. Transfer volatile samples

Pay attention to two points: First, be sure to rinse twice before pipetting; Second, drain as soon as possible after pipetting.

2. Remove high viscosity samples

In the reverse pipetting mode: press the suction/discharge button to the second gear (second stop point) while aspirating, and press the button to the first gear (first stop point) during draining. In addition, a residence time of 3-5 seconds is required for both aspiration and drainage.

3. Transfer high density / low density samples

The accuracy values of the pipettes are based on the transfer of pure water. If the density of the sample differs greatly from the density of the water, the accuracy will be much worse. Therefore, it is necessary to first understand the density of the sample before pipetting, and then adjust the range to the product of the volume and density of the sample to be transferred. For example, if the density of a sample is 1.2g/cm3 and you need to transfer 300ul, you should set the range to 360ul. This is only a rough adjustment method, and the strict adjustment method also needs to use the gauge or balance as an auxiliary tool for accurate calculation.

4. Pipette high temperature / low temperature samples

There are three points to be aware of when removing high temperature/low temperature samples: first, it is absolutely impossible to rinse the tips before pipetting; second, each nozzle must be replaced with a new one; third, aspiration and platooning The liquid should be completed as soon as possible.