Hot plates and magnetic stirrers are critical components in almost any laboratory as they assist in the basic heating and mixing of chemicals or samples.
What Is a Hot Plate?
Hot plates are used in a laboratory as a heat source that can uniformly heat solutions and materials. They are considered much safer than traditional Bunsen burners because there is no open flame involved, just a heated plate.
Types of Hot Plate
Many different variations of hot plate have been developed to support a variety of needs. The plate can be made up of different materials and there are different layouts regarding temperature control.
Aluminum
Aluminum is a great conductor of heat which makes this kind of hot plate heat quickly and evenly. It is very easy to clean after cooling. However, an aluminum plate is not recommended if any of the materials to be heated are corrosive. Aluminum is susceptible to corrosive materials and will degrade and rust in their presence.
Ceramic
Ceramic is very resistant to corrosion and can handle high temperatures. The light coloration of its surface makes viewing samples and solutions much easier for reaction changes. Use caution as it can crack if handled roughly or incorrectly.
Glass
Glass is another easy plate to observe your sample through. It is easy to clean, resistant to corrosion, and heats effectively. There is less heat transferred beyond the glass which may reduce the occurrence of accidental burns if other portions of the hot plate are touched.
Additional Features to Consider When Purchasing a Hot Plate
- Digital or Analog temperature controls
- Varying voltages
- Plate shapes can come in circles or squares
- The variety of sizes for specialized analytical needs
Pros
- Hot plates are very cost effective
- They are extremely easy to use
- They support a variety of essential laboratory procedures
- Hot plates are easily portable
Cons
- Safety is important when working with a hot plate, so they must be kept in a secure location away from flammable materials
- Additional gloves or tongs must be purchased to remove heated materials from the hot plate to avoid burns
- The appropriate plate material and temperature range must be purchased or the longevity of the hot plate may be compromised
What Is a Magnetic Stirrer?
A magnetic stirrer is an essential piece of equipment for most laboratories. Certain procedures require a solution to be agitated in order for it to be effectively dissolved. This can be for
- Ensuring a homogenous mixing of sample prior to analysis
- Combining a variety of chemicals into a solution
- Getting solid materials to dissolve in a liquid solution
- Meeting a variable rotating speed required in a preparatory method
Types of Magnetic Stirrers
Magnetic stirrers are typically your go to when you are needing to mix small volumes. If you are needing to mix large volumes, check out overhead stirrers instead. There are two main types of magnetic stirrers; multi position stirrers and individual stirrers.
Multi Position Magnetic Stirrers
Does your process require you to simultaneously mix a large number of solutions or reagents at once? If so then the multi unit option may be the magnetic stirrer for you because you can blend multiple solutions at once. This design is
- Space Saving
- supporting pH and temperature probes, making it perfect for buffer preparation
- Quiet and powerful
Individual Magnetic Stirrers
Certain processes require solutions to be mixed individually. This could be due to limited space in a fume hood, needing to eliminate cross contamination risks, or general safety. Just make sure to choose a magnetic stirrer sized that is adequate for the beaker container you will be mixing in.
- Some models can support hugely different volumes, even from 200-10,000ml!
- They are strong enough to maintain their rotation speed even when you’re adding additional reagents
- They can support a wide range of analytical uses with an RPM range of 0-1500rpm.
Make Sure to
- Use the right size and shape stir bar that isn’t too large or too small for your process
- Purchase a magnet bar retriever so you can remove your magnet from the solution without contamination
- Watch to make sure your magnet isn’t damaged because scratches can contribute to contamination
What is a Hot Plate Magnetic Stirrer?
A hot plate magnetic stirrer is a hot plate with an added bonus, it has a magnetic inside of it. The magnet can be rotated at varying speeds which will create a magnetic field around the hot plate. Paired with a magnetic stir bar, your solution can be heated and mixed at the same time.
Pros
- Being able to simultaneously heat and mix chemicals, solutions can be developed quickly and easily.
- They have easy rotational speed and temperature adjustments
- There are timer functions making it easy to track the length of time a solution is agitated
- They eliminate the need for externally stirring the solution, which saves employee time in prep work
- It saves valuable bench space by having two pieces of equipment in one
Cons
- They usually have a maximum capacity around 4 Liters
- They are more of an investment than the standalone hot plate or magnetic stirrer
Conclusion on Differences Between Hot Plates and Hot Plate Magnetic Stirrers
When trying to determine whether you should buy a hot plate or a hot plate magnetic stirrer, take the time to evaluate your process. Also, keep safety in mind when looking at the different options. Hot plates can be purchased at a reasonable price, but digital temperature readouts, built in off switches that turn off when the temperature max is exceeded, and timers can be worth the added cost. Preventing injury and promoting quality lab procedures are well worth investing in. The efficiency of having two pieces of equipment in one is well worth investing in. these are the Differences Between Hot Plates and Hot Plate Magnetic Stirrers.
References
“Hot Plates Information.” Hot Plates Selection Guide | Engineering360
TecnoMaster. “Features and Uses of the Magnetic Hotplate Stirrer.” KALSTEIN FRANCE, 23 July 2018
“Lab Magnetic Stirrers and Hotplate Stirrers: Choosing the Best One for Your Laboratory.” LaboratoryApp
