Lab Centrifuge Explained: How It Works & Why You Need One

Summary:

A centrifuge spins sample buckets at high speed, generating a centrifugal force that drives the contents of the sample outward based on their density. This equipment is essential to biological, chemical, and clinical processes.

Introduction to Laboratory Centrifuges

A laboratory centrifuge is a critical equipment in nearly every research and clinical facility. It plays a significant role in separating particles from liquids based on density, making it easier for lab technicians and scientists to conduct experiments and diagnostic tests. Whether in clinical labs, research institutions, or industrial applications, centrifuges play a key role in isolating cells, purifying proteins, and separating blood components.

How a Lab Centrifuge Works

At its core, centrifugation is separation through sedimentation. A centrifuge uses a motor to spin liquid samples at high speeds, generating a powerful centrifugal force.

Centrifugation is influenced by:

• The density of the samples and the solution

• The temperature and viscosity

• The distance that the particles are displaced

• The speed of rotation

Centrifugal speed is measured in revolutions per minute (RPM) or relative centrifugal force (RCF), also known as g-force. The RPM measures the speed of the rotor, and the RCF measures the force exerted on the sample, which is what separates the components based on density.

The centrifuge’s rotor is central to the centrifugal process. As the rotor spins, it generates a centrifugal force that drives denser particles to sink to the bottom of the container, while more lightweight particles remain suspended.

Types of Laboratory Centrifuges

Centrifuges come in various sizes, each designed for specific applications. Whether you are working with small sample sizes, large volumes, or temperature-sensitive materials, there is a centrifuge that suits your needs. The most common types of centrifuges are:

1. Microcentrifuges

Microcentrifuges separate samples with smaller volumes, such as 2 mL, 1.5 mL, 0.5 mL, and PCR tubes. They are usually operated at 12,000 to 13,000 RPM speeds, while more specialized equipment can reach speeds of 30,000 RPM.

These centrifuges are typically used for molecular separations of cell organelles like nuclei, DNA, and phenol extraction. They use tube samples that are smaller in size when compared to the standard tubes used in larger centrifuges.

Some manufacturers also offer interchangeable rotors and tube adaptors that facilitate the use of larger test tubes along with smaller ones. Depending on the nature of your research, microcentrifuges also come with temperature controls that make them suitable for temperature-sensitive research.

2. Benchtop centrifuges

Benchtop centrifuges are characterized by their small bench space footprint. They can be used for clinical and laboratory research, including cell separation and routine sample preparation. They are ideal for separating small volumes of samples, such as yeast cells and red blood cells.

These centrifuges are driven by an electric motor, where the tubes are rotated about a fixed axis, swinging bucket, or continuous flow, depending on the model you are using. Benchtop centrifuges' speeds range between 200 and 6,000 RPM for clinical benchtop centrifuges.

Refrigerated benchtops feature interchangeable rotors and adaptors to accommodate a wide range of sample volumes from under 1 mL to a few litres, at a maximum speed of 60,000 RPM.

3. Refrigerated centrifuges

In addition to rotors and racks for sample tubes, refrigerated centrifuges are equipped with a cooling technology for temperature-sensitive materials. They typically use a compressor or thermoelectric cooling technology to keep temperatures between -20 degrees Celsius and- -40 degrees Celsius.

They are ideal for collecting substances that separate rapidly, such as yeast cells, chloroplasts, and erythrocytes. They can also analyze DNA, RNA, PCR, and antibodies. 

Refrigerated centrifuges are designed to handle larger sample volumes with speeds ranging from 6,500g to 60,000g.

4. Ultracentrifuges

Ultracentrifuges are the most sophisticated type of centrifuges available. They are used for specialized tasks such as isolating subcellular components, macromolecules, and viruses. They can reach speeds of up to 100,000 RPM, and are equipped with cooling technology to balance the heat produced by such intense spinning.

These centrifuges are divided into two categories - preparative and analytical - based on your lab's specific needs. Preparative centrifuges are commonly used for separating large biomolecules, while analytical ultracentrifuges are used to study macromolecules in real time.

• Preparative Ultracentrifuges: These centrifuges are essential for separating large biomolecules and subcellular components such as lipoproteins from plasma. When a run is prepared for an ultracentrifuge, the contents of the tube are examined after the centrifugation process.

• Analytical Ultracentrifuges: These centrifuges are equipped with advanced, optimal systems that allow scientists to observe the behavior of macromolecules during centrifugation. They are used to study molecules' size, shape, and interaction, making them essential for biophysicists and biochemists.

5. Beckman Coulter Centrifuge

Beckman Coulter centrifuges are designed for accuracy and reliability. These centrifuges can reach 100,000 to 150,000 RPM and are designed for maximum efficiency and resolution.

Key Features to Look for in a Laboratory Centrifuge

Here are some of the things to look for when choosing a laboratory centrifuge:

• Speed (RPM and RCF): How fast do you need your centrifuge to go? Speed is an essential factor in the functionality of your equipment. But remember that RCF, the force exerted on samples, is more important than the RPM (the rate at which the rotor is spinning).

• Rotor Compatibility: Each centrifuge model is compatible with a limited set of rotors and accessories. The main styles of rotors available are fixed-angle and swing-out rotors. Swing-out rotors work for applications that involve sedimentation and radiant separation. Fixed-angle rotors are great for pelleting applications (cells, bacteria, DNA, proteins) and high-speed ultracentrifugation.

• Capacity: Another factor to consider when choosing a centrifuge is the volume and number of samples you will be processing at any time. Some centrifuges are designed for smaller volumes and sample processing, while others allow many samples.

• Temperature Control: Many centrifuges run at room temperature without heating or cooling options. However, if you plan on working on temperature-sensitive materials, consider refrigerated centrifuges.

• Safety Features: Some safety features include an electronic lid-lock, which prevents the lid from being opened accidentally while the equipment runs. You should also consider imbalance sensors, which stop the centrifuge if a high level of imbalance is noticed.

Why You Need a Lab Centrifuge

Centrifuges are essential equipment in microbiology laboratories. Some of the reasons you need them include:

• Efficient Separation of Components: Centrifuges allow for the rapid and efficient separation of different components within a sample. This capability is critical for many microbiological processes, including isolating cells from culture media, DNA, RNA, and purifying proteins and nucleic acids.

• High Throughput and Consistency: Centrifugation enables the processing of multiple samples simultaneously, speeding up laboratory processes while ensuring consistency of results.

• Precision and Sensitivity: Centrifuges can achieve high speeds and apply centrifugal force, allowing for the separation of even the tiniest particles, such as viruses and subcellular organelles. Precision and sensitivity are essential for detailed analysis and accurate results of laboratory processes.

• Versatility: Some centrifuges come with accessories that can be customized for diverse purposes. From basic cell harvesting to advanced molecular biology, centrifuges can be adapted to meet the specific needs of different experiments and protocols.

Buying Guide: Choosing the Right Laboratory Centrifuge

As crucial as centrifuges are to laboratory processes and experiments, not all suit you. The problem may be price, space available, or even the speed and model of the equipment. We are experts in choosing the right laboratory centrifuges:

• Define Your Requirements: Begin by clearly defining your centrifugation needs. Consider factors such as application or usage (molecular biology, clinical testing, etc), type of samples you will be processing, desired throughput, speed, and capacity.

• Consider Lab Space: Examine your space and how it might affect your choice of equipment. If you have little space, consider getting a microcentrifuge or benchtop centrifuges, and if you have more space, a floor model or high-powered option like an ultracentrifuge is best.

• Budget and Warranty: Getting a centrifuge is an expensive endeavor. But your budget should not be the reason you’re buying ill-fitted equipment. You can get a high-quality used centrifuge at the R&D Laboratory Equipment for easy money. We also offer a warranty on our products.

• Compatibility with Existing Infrastructure: Ensure that the chosen centrifuge is compatible with your existing laboratory infrastructure, including power requirements, available bench space, and compatibility with ancillary equipment such as tube adapters and accessories.

Maintenance & Best Practices for Lab Centrifuges

To keep your centrifuge in top condition, follow these simple tests:

• Clean regularly with neutral solutions like alcohol or alcohol-based disinfectants.

• Regularly lubricate the centrifuge, especially the O-rings, which prevent sample leakage.

• Train laboratory technicians and attendants on the proper usage and handling of centrifuges.

• Always check for scratches or chemical exposure on the rotor.

• Schedule regular professional maintenance.

Conclusion

Your research facility is incomplete without a laboratory centrifuge to help ensure the accuracy of results and efficient analysis. However, you need to be careful when picking a centrifuge for your laboratory, because not all equipment will fit your needs or existing infrastructure. This is when you should consult with a professional lab equipment seller like R&D Laboratory Equipment for expert advice and guidelines on laboratory centrifuges for sale. You can also reduce your costs by getting a high-quality used centrifuge online.

FAQs

1. What is the working principle of a centrifuge?

A centrifuge operates on the principle of separating substances based on density through sedimentation, which is driven by a centrifugal force.

2. Why do you need a centrifuge?

You need a centrifuge for efficient analysis and experimentation on molecular properties, biological samples, viruses, etc.

3. How do you care for and maintain a centrifuge machine?

Clean the chamber, rotor, adapters, and external surfaces daily with a soft cloth soaked in alcohol-based disinfectants.

4. What is the function of a centrifuge in a laboratory?

Centrifuges are used in chemistry, biology, biochemistry, and clinical medicine to isolate and separate substances.

5. How does a centrifuge work?

A centrifuge spins at high speed, generating enough centrifugal force to separate substances in test tubes based on density.

6. Why is it called a centrifuge?

A centrifuge gets its name from the centrifugal force - the virtual force that pulls spinning objects outward.

7. What are the benefits of a centrifuge machine?

Quick and efficient separation of substances, precise results for diagnostic and research purposes, and versatility in application across various industries are advantages of getting a centrifuge.

8. What is the lifespan of a centrifuge?

A centrifuge can last more than 10 years when properly operated and maintained.

9. What are the main parts of a centrifuge?

The basic components of all centrifuges are the rotor assembly and the electrical motor.

10. Where can I find a laboratory centrifuge for sale?

You can get a second-hand centrifuge for sale at R&D Laboratory Equipment.