Separating Suspensions Like A Pro: A Complete Guide About Centrifuge, Its Types and Applications

Let’s face it. The world of science constantly demands precision and separating suspensions can be our greatest puzzles. Separating these components can feel like an impossible feat because you think that might take forever. But what if there’s a better way to achieve fast, efficient and precise precisions? You’re right, the centrifuge machine is here to save the day.

Centrifugal machines or better known as centrifuges are powerful tools that utilise centrifugal force to rapidly separate mixtures. By spinning a sample at high speeds, this machine can achieve what traditional methods might take hours to accomplish, all while delivering cleaner and more complete separations.

In this guide,  we'll explore how these remarkable machines work, the numerous benefits they offer, and the diverse applications they excel at. So, say goodbye to the frustration of traditional methods and separate your suspensions like a pro.

Different Types Of Centrifuge

These centrifugal machines come in all shapes and sizes, each designed to tackle specific separation challenges. Just like choosing the right tool for the job, selecting the appropriate one ensures optimal results in your experiment. Here's a glimpse into some common types:

Benchtop Centrifuges

These compact workhorses are the go-to for many routine laboratory tasks. They offer moderate speeds and are ideal for separating everyday samples like blood components or isolating cells from a suspension. Their small footprint makes them perfect for space-constrained labs.

High-Speed  Centrifuges

As the name suggests, these machines spin at extremely high speeds that can reach up to several hundred thousand RPMs. This incredible force allows them to separate very small and dense particles, like viruses or nanoparticles. However, their high speeds require specialised rotors and strict safety procedures.

Refrigerated Centrifuges

Maintaining a consistent low temperature is critical for separating heat-sensitive biological samples. That’s why these devices come equipped with a refrigeration unit that keeps samples chilled throughout the process. They are effective in preventing samples from degrading and are very useful for isolating proteins or studying enzymes.

Microcentrifuges 

These tiny champions are perfect for working with small sample volumes, typically a few hundred microlitres. Often used in molecular biology research, they can separate cellular components or isolate DNA from a sample. Their compact size makes them ideal for personal workstations.

Ultracentrifuges

Ultracentrifuges are often referred to as the ultimate speed masters of its world. The reason? These machines can reach speeds exceeding a million RPMs. Because of those characteristics, ultracentrifuges are used for highly specialised tasks like separating isotopes or purifying macromolecules. They are typically found in advanced research facilities.

Choosing the Right Settings

These contraptions aren't one-size-fits-all. As mentioned before, different types spin at different speeds. This is why choosing the right speed is crucial for achieving a successful separation of your solutions.

Just imagine trying to separate sugar crystals from the sand. At a slow speed, both might settle together. But increase the speed, and the denser sugar crystals will be pushed outwards much faster, leaving the lighter sand particles behind. This is where understanding your sample and the desired outcome becomes important.

Here are some factors to consider when choosing the right speed:

• Particle size and density: Denser and larger particles require higher speeds for effective separation.
• Sample volume: Larger volumes might necessitate lower speeds to avoid wobbling or uneven separation.
• Desired purity: Higher speeds can achieve a cleaner separation, but they can also damage delicate samples.

If you're unsure about the ideal speed for your experiment, consulting the user manual, or reference scientific protocols relevant to your sample is always a wise move.

How To Use A Centrifugal Machine:  A Step-by-Step Guide

Now that you’ve chosen the right centrifugal machines for your experiment, let's navigate the process of using them safely and effectively. While specific protocols may differ according to  your equipment and sample, here's a general step-by-step guide to get you started:

1. Prepare Your Samples

Before you start at anything, ensure your samples are properly balanced. This is crucial for maintaining smooth operation at high speeds. You can utilise pre-weighed tubes or balancing scales to achieve this as any other lab does. Unevenly balanced tubes can cause the machine to wobble, potentially leading to damage or inaccurate results.

2. Load and Secure

Next, carefully place your balanced sample tubes into the rotor or the rotating part of the machine. For proper positioning, refer to the user manual for proper loading positions specific to your machine. Once loaded, securely fasten the lid. This extra step will prevent any mishaps during your operation.

3. Set Your Parameters

Most of these clarifying machines let you adjust speed (RPM or revolutions per minute or relative centrifugal force (RCF) and centrifugation time.  So, to get the right settings for your sample and desired outcome always check your user manual or established laboratory protocols. Ideally, higher speeds and longer times generally result in a cleaner separation. But remember, some samples might be delicate and require gentler settings.

4. Run and Monitor

Once everything is set and secure, start the centrifugation cycle. Make sure to observe the machine during operation, listening for any unusual noises or vibrations. If anything seems off, immediately stop the run and consult the user manual for troubleshooting steps.

5. Stop and Open Safely

After the cycle is complete, the machine will slow down to a stop. Important: Don't open the lid right away! This is because opening the lid while the rotor is spinning can be dangerous and may lead to mishaps. So, wait patiently for the rotor to come to a complete stop. 

6. Retrieve Your Samples

Once the rotor has stopped completely, carefully open the cover to get your samples. Now, the magic happens! Your previously murky suspension is not neatly separated, with your desired component settled at the bottom of the tube, ready for further investigation.

Tips for Maximising Performance

There's always room for improvement, right? And so, let’s talk about some helpful tips and tricks for optimising your centrifugal machine and achieving the best possible results.

Balancing is Key

Unevenly balanced tubes can lead to a wobbly machine, potentially damaging the equipment or affecting separation efficiency. So, invest in a balancing scale for precise balancing, especially when working with multiple samples.

Choose the Right Tubes

Different types of these separating machines require specific tubes. Make sure you're using tubes designed for the model you are using and compatible with the type of sample you're working with. Plastic tubes are common for general use, while glass tubes might be preferred for specific applications.

Mind the Temperature

Temperature control is very critical for certain samples. So, if you are working with biological materials that are sensitive to heat such as enzymes or proteins, use refrigerated clarifying machines to avoid damage to these molecules during the process.

Less Means More (Sometimes)

Sometimes, less volume means more when you think about sample volume. So use less sample volume in your tubes. Filling tubes to their maximum capacity may result in spillage, and in some cases, even the breakage of the tube, during high-speed runs. This is why you must stick to the recommended filling volumes specified in your machine’s user manual.

Cleaning and Maintenance

Just like how you care for other lab equipment, proper care, and maintenance are very important too for your centrifugal machine. And this could only mean one thing- optimum performance and a longer life span for the equipment. So, regularly clean the rotor and also the chamber to prevent the buildup of sample residue. This has been said many times and again, check your user manual as well for specific cleaning procedures and recommended cleaning schedules.

Safety First

This cannot be stressed enough. Just like any other lab tools, these machines are powerful, and safety should always be your top priority. Familiarise yourself with the safety protocols of your specific model. Most importantly, wear appropriate personal protective equipment (PPE) like lab coats,  gloves, and eye protection when operating the equipment.

Supercharge Your Separations With Science Equip

All in all, the true workhorse in any lab is not the fanciest equipment, it’s the centrifuge. While microscopes and Bunsen burners  may often steal the spot, these unassuming lab tools silently separate mixtures. And with a wide array of options, finding the right ones for your scientific journey can be overwhelming. But worry less, because we’ve got you covered.

At Science Equip, we're passionate about empowering scientists with the right tools to make groundbreaking discoveries. More than that, our platform is also your one-stop shop for all things centrifugation.  We offer a selection of laboratory equipment from leading manufacturers, catering to every separation challenge and a budget that’s within your pocket’s reach.