If you have a carpenter’s level handy, you can confirm that the surface is completely level. Set the level on the tabletop or counter, and make sure that the horizontal bubble is completely centered in its glass tube. If you’re using a very large centrifuge that rests directly on the floor of your lab, you can skip this step.
If you’re confused about which size tube to use with which size centrifuge, consult a more experienced laboratory technician. Or, consult the manual for the centrifuge you’re using. Most tabletop mini centrifuges take a 1. 5 mL microtube or a 0. 5 mL tube.
For example, if you fill the first microtube with 10 mL of solution, make sure that all of the other microtubes you plan to use for the experiment are filled with 10 mL of solution. A microtube filled with 9 or 11 mL could unbalance the centrifuge.
Or, if your microtubes have marks on the side indicating the amount of liquid in the tube, make sure that all tubes are filled to the same level. [5] X Research source Balance tubes are commonly filled with water. However, if the solution you’re using in the experiment has a density much higher or lower than that of water, use a liquid with a similar density in the balance tubes.
By adding 1 equally weighted tube on either side of the centrifuge, you’ll keep the center of gravity exactly in the middle of the centrifuge rotor.
Create a system so that you know which tubes are microtubes and which are balance tubes (if the liquids are the same color). You could put a small sticker on top of the sample-filled microtubes, or use a blue marker to color a small dot on top of the balance tubes.
Continuing the example, after you’ve added microtubes at 3 o’clock and 9 o’clock, you could add 2 more at 2 o’clock and 8 o’clock and another pair at 11 o’clock and 5 o’clock. If you have an odd number of microtubes, you’ll need to balance the centrifuge using an alternate configuration.
The clock positions work well when balancing a 12-hole centrifuge. Other common sizes include centrifuges with 24 and 30 holes.
Balance the centrifuge with 6 microtubes using the same configuration, but swap out the balance tube for a sample-filled microtube.
You can balance a centrifuge using 8 microtubes in the same configuration. Just replace one of the microtubes with a sample-filled tube.
