Improper cleaning and maintenance of plastic beakers can lead to contamination or equipment damage that can compromise your experiments and lab results. If you’re working with basic solutions or more volatile substances, making sure this lab equipment is in top shape is important.
In fact, the Victoria Department of Health has released cleaning and waste disposal procedures, including proper cleaning, sterilisation, and maintenance of labs for infection control. The health department also endorsed AS/NZS 2243.3:2022 guidelines for lab safety. These guidelines emphasise the importance of maintaining equipment, such as your beakers, for contamination prevention and reliable results in laboratory work.
In this guide, we will explore the comprehensive guide about caring for these lab resources, from cleaning protocols to sterilisation methods and maintenance tips. By the end of this article, you will have a clear set of protocols that will help you extend their life and keep your lab running smoothly.
What Are the Types of Plastic Used in Beakers?
Beakers are made from various plastic materials, and each type has different strengths and weaknesses. Here are the most common types used in lab beakers and what you need to know about them.
- Polypropylene. This material is known for its chemical resistance, meaning it can withstand most acids, bases, and solvents without breaking down. This is one of the most durable materials to work with.
- Polycarbonate. It is commonly used when you need to clearly see your liquid measurements. However, it’s less resistant to harsh chemicals compared to polypropylene, so take care when selecting cleaning agents.
- Teflon (PTFE). Highly resistant to nearly every chemical, Teflon beakers can handle extreme temperatures and corrosive substances. But be cautious, as they can be more expensive than other types.
Knowing which type your beaker is made of helps you choose the right cleaning and sterilisation methods, so that they last longer and stay effective.
Basic Cleaning Protocols for Plastic Beakers
Cleaning the equipment requires attention to detail to prevent damage and guarantee cleanliness. Using inappropriate cleaning agents or tools can degrade the plastic that can impact your beakers' lifespan and contaminate your experiments. So follow these steps to clean them thoroughly and effectively.
1. Start with a Pre-Cleaning Rinse
Before using any soap or detergent, start by rinsing them with distilled water. This initial rinse removes any loose particles or residue left over from previous experiments. Tap water may contain minerals or impurities that could react with cleaning agents, so always opt for distilled water.
If you’ve just used them to mix a saline solution, a quick rinse with distilled water will wash away any salt crystals or residues that might otherwise interact with cleaning agents or detergents. This step reduces the amount of scrubbing needed later.
2. Get Hands-On with Manual Cleaning
Once you’ve done the initial rinse, it’s time for manual cleaning. Use a mild, lab-grade detergent that’s safe for the material. Avoid bleach, ammonia, or any abrasive chemicals, as these can degrade them over time.
- Detergent choice. Look for detergents formulated for lab equipment, such as Alconox or Liquinox, which are known for being gentle on plastic yet effective at removing residues.
- Soft brush scrubbing. Use a soft brush to scrub the inside and outside of them gently. Focus on areas where residue is likely to accumulate, such as the bottom, the sides, the base, and the spout.
If you’re cleaning a graduated beaker, make sure to clean around the graduations carefully. A soft brush will remove any stains or markings without rubbing off the measurement lines for accurate measurements in future experiments.
3. Soak for Stubborn Stains
Sometimes, residues cling to them despite your best scrubbing efforts. In these cases, fill them with warm, soapy water and let them soak for 10–15 minutes. Soaking loosens stubborn stains, making them easier to remove.
- Avoid hot water. It can warp certain types, such as polyethylene or polycarbonate. Always stick to lukewarm water to prevent damage.
- Tip for protein-based residues. If they held substances that can leave protein-based stains (like certain biological samples), try using a protease enzyme cleaner. It’s designed to break down proteins and can be more effective than standard soap alone.
For tough stains, such as those from dried-on chemical solutions, add a small amount of enzyme-based cleaner to warm water and soak them for 10–15 minutes. After soaking, gently scrub the residue with a soft brush to ensure a spotless finish.
4. Rinse with Distilled Water
After cleaning, rinse them again with distilled water. This final rinse removes any detergent or cleaning solution residues, which could interfere with future experiments by altering the chemical composition of the beaker’s contents.
- Distilled vs. deionised water. While both types of water are pure, distilled water is preferred for lab equipment rinsing since it’s free of any ions that might remain after deionisation.
- Multiple rinses. For heavily soiled beakers, consider a series of two or three rinses to be absolutely certain that all soap or detergent has been removed.
After cleaning, let’s say, your beaker 150 ml used in pH-sensitive tests, a final rinse with distilled water makes sure that no soap residue remains, which could alter the pH of any future solutions placed inside these lab cups.
5. Finally, Air-Dry
Drying is the final step, and to avoid contamination, place them upside down on a clean, dry surface to air dry. Avoid using towels, as they can introduce lint, fibres, or even residue from fabric softeners that may interfere with your work.
- Drying rack. A lab-grade drying rack with pegs allows air to circulate inside them as they dry, reducing the chances of moisture buildup.
- Why not towels? Although towels might seem quicker, they often shed tiny fibres or lint. These particles can cling inside and contaminate your solutions or interfere with measurements.
When drying your plastic beaker polypropylene, using a drying rack rather than a towel minimises any chance of particle contamination.
Final reminder: Avoid using abrasive cleaning tools such as steel wool or scouring pads, as these can scratch their surface. Even minor scratches can harbour bacteria or chemicals, which may contaminate future experiments or cause them to wear down prematurely.
Always use gentle cleaning methods, especially for those exposed to corrosive chemicals or undergo frequent cleaning, as maintaining lab equipment like beakers with plastic polypropylene extends their lifespan.
Sterilisation Protocols for Plastic Beakers
Plastic is sensitive to heat and certain chemicals, which can cause warping, degradation, or chemical leaching, so sterilisation requires a careful selection of methods. Here are some sterilisation techniques that maintain their shape.
Autoclaving
While some types, such as polypropylene, are more resistant to heat, you should set the autoclave to a lower temperature than you would for glassware. A typical setting is 121°C, but always refer to the supplier’s guidelines for your specific type.
- How to autoclave them. Place them on an autoclave tray with the open end facing down. This positioning prevents water from pooling inside during the sterilisation cycle. It’s also helpful to avoid stacking them too closely for even heat distribution.
- Types of plastic that can be autoclaved. Look for the ones specifically labelled as autoclavable, such as high-density polyethylene (HDPE) or polycarbonate. However, softer ones like polystyrene are likely to warp or melt, so avoid autoclaving these types.
Chemical Sterilisation
When autoclaving isn’t suitable, chemical sterilisation provides a safe alternative. Mild disinfectants, like ethanol (70%) or hydrogen peroxide (3%), are used to eliminate bacteria and viruses. Be careful to select chemicals that won’t degrade or discolour them, especially if you’re working with sensitive solutions in future experiments.
- How to use chemical sterilisation. Pour enough disinfectant into the cup to cover the entire surface area, swish it around for 1–2 minutes, then rinse thoroughly with distilled water. Make sure you completely remove any chemical residue to avoid contaminating future experiments.
- Avoiding harsh chemicals. Avoid bleach or highly acidic solutions, as they can cause chemical reactions with the material. Bleach can weaken its structure over time, which can lead to cracks or clouding.
UV Sterilisation
This is ideal for plastics that are sensitive to heat and harsh chemicals. UV-C light, in particular, is effective at breaking down bacterial DNA and rendering viruses inactive. This method doesn’t involve any moisture or heat, so it’s perfect for delicate ones and quick sterilisation between uses.
- How to UV sterilise them. Place it under a UV-C lamp for a few minutes and rotate it if necessary to expose all surfaces. Be cautious not to overexpose, as prolonged UV exposure can cause them to become brittle over time.
- Protective measures. Since UV light can be harmful to the skin and eyes, wear protective gear and only handle UV sterilisation in a controlled environment. Make sure that it is free of dust or residues before UV sterilisation, as these can block the light and reduce effectiveness.
Pro tip: After any sterilisation method, let them cool or air out fully before reuse. Sterilisation processes can temporarily alter their structure, and using them immediately afterwards can lead to inaccuracies, especially if they haven’t returned to their original shape or if residues haven’t fully evaporated.
Maintenance Tips for Prolonging Their Lifespan
Proper maintenance extends the life of your beakers and makes accurate and reliable results. Here’s a quick rundown to keep your materials in top shape.
- Storage. Store them in a cool, dry place, away from direct sunlight. Exposure to UV rays can cause them to degrade over time and lead to brittleness or yellowing.
- Avoid high temperatures. Even when not in use, it’s best to keep them away from heat sources like radiators or ovens, as this can warp the plastic.
- Routine inspection. Check for scratches, cracks, or discolouration regularly. These are signs that they may need to be replaced.
- Use covers. Using a beaker cover plastic can prevent dust or other contaminants from entering inside it when it’s not in use.
And don’t forget, handle them gently, especially when filled with chemicals or during cleaning. Rough handling can cause minor cracks that could go unnoticed but may lead to leaks or contamination over time.
Commit to Lab Maintenance and Sterilisation
Together with your other lab equipment, the longevity of plastic beakers is a priority for cost-effective lab maintenance. A well-maintained beaker means accurate results, safety in the lab, and fewer costly replacements.
For all your lab equipment needs, contact us for a trusted supplier to help you stock up on quality lab supplies.
