An ultrasonic bath is an important piece of equipment in many laboratories. They are useful in various applications including degassing, cell lysis, cleaning, and more.
Using a bath improperly can cause a range of issues, including safety risks, ineffective ultrasonic processes, or a shorter lifespan of your bath.
Here, we look at the key best practices to follow when using an ultrasonic bath:
- Use a basket or other means of suspension
- Choose the appropriate solution
- Don’t use flammable liquids
- Don’t put your hand in the bath
- Ensure the tank is filled properly
- Ensure the right temperature
- Thoroughly read the manual
Let’s look at each of these in a bit more detail:
1. Use a Basket or Other Means of Suspension
It’s important that objects placed in the bath don’t come into contact with the base of the tank. This is typically where the transducers are attached. If objects (particularly dense or heavy ones) come in contact with these, it can affect their operation, and even cause permanent damage.
Instead, any objects, including vessels such as beakers or tubes, should be suspended in the tank. This is usually done by means of a wire basket, but wires and a cross-bar or some other method of suspension could be used in some cases.
A beaker position cover such as the one below offered by Branson may be used to hold beakers in place.
If you’re using a basket and have objects that are small enough to fit through the holes, you could place these in a vessel, such as a glass beaker, which should also be filled with the same solution as the tank.
2. Choose the appropriate solution
An important factor to consider when setting up your ultrasonic process is what solution you will use. In many cases, distilled or demineralized water will be optimal. Tap water may contain calcium carbonate and other impurities that could lower the effectiveness of the ultrasonic process or damage the bath. That said, you shouldn't use water that's too pure, since water beyond a certain purity will become more corrosive to the tank. For this reason, deionized water may not be the best option.
In other cases, there will be more suitable alternatives. For example, if you’re lysing cells, you’ll need to use an appropriate buffer solution. If you’re using your bath for cleaning, there are a range of detergents available, including alkaline and acidic solutions. The one you choose will depend on the material of the object you're cleaning and the contaminants you're trying to remove.
3. Don’t Use Flammable Liquids
Ultrasonic cavitation is a heat-generating process. As such, it’s not safe to use a flammable liquid such as alcohol or acetone in a standard ultrasonic bath. Use of any volatile liquids should be avoided.
There are also other concerns with using unsuitable fluids in an ultrasonic bath. Some materials could damage the tank or pose a health risk when subjected to heat and ultrasonic waves.
4. Don’t Put Your Hand in the Bath
Hands and all other body parts should be kept out of the bath, especially when it is running. Many solutions used in ultrasonic baths have the potential to cause mild to severe skin irritation. What’s more, although the effects of ultrasonic cavitation on skin are not widely studied, it could also cause irritation.
5. Ensure the Tank is Filled Properly
Before switching a unit on, it’s important to ensure it’s filled with solution to the recommended level. If you switch the unit on dry, you will likely cause the transducers (the parts that provide the ultrasonic waves) at the base of the unit to burn out.
6. Ensure the right temperature
Depending on your application, you may need to apply heat. Heat can speed up degassing, cleaning, and other processes. If you have a unit that has heating capability, ensure you use the appropriate setpoint temperature. Too high a temperature could cause unwanted reactions, damage to objects, and other issues.
The Bransonic 0.5 Gallon Ultrasonic Bath comes in a heated and unheated version.
7. Thoroughly Read the Manual
As with any new piece of equipment, you should always go through the manual for your ultrasonic bath prior to use. This will provide you with all the information you need to use the equipment safely and efficiently. It should also offer proper cleaning and maintenance instructions to help ensure you prolong the lifespan of the unit.