Within a laboratory, we take all kinds of samples care daily, which can contain from infectious agents to chemical residues that can alter the results of a sample; For this reason, as part of the work routine, laboratory material needs cleaning disinfection and sterilization, so that it can use it later with no problem.
Although in most laboratories there is specific professional cleaning personnel for the cleaning and sterilization area, it never hurts to know the mechanisms, especially for students who enter the school laboratory where they perform experiments and later have to clean the laboratory equipment.
To carry out any work in the laboratory correctly, it is necessary to always keep the material and the work table clean. The material must be clean and dry before starting the experiment.
Laboratory equipment needs cleaning immediately after each operation since it is much easier and the nature of the residues it contains.
To clean an object, the residue is first removed (which is thrown into the container) with a spatula or rod, and then clean with the solvent. Soapy water is one of the best cleaning methods. Occasionally, acids, bases, or organic solvents are used to remove all difficult residues.
Security considerations
When washing glass items, chemical-resistant, non-slip safety gloves, and safety goggles should be worn. Depending on the cleaning solutions and detergents used, it may be necessary to use an apron and a fume hood. Always check with the Safety Department before using caustic solutions.
Cleaning of laboratory glassware
To wash the material, you can use soap, detergent, or cleaning powder (with or without abrasives). The water must be hot. If the material is extremely dirty, we will get better results by using a cleaning powder with a very light abrasive action. The abrasive must not scratch the glass.
I must do immediately it after use. The most common procedure comprises washing the material with detergent, using a suitable brush, then it needs a thorough cleaning, first with plenty of tap water and then with distilled water.
If the professional cleaning is not complete with the detergent, we can use a commercial acid solution or alcoholic potash. In stubborn cases, we can use a sulfochromic mixture (solution of potassium dichromate and sulfuric acid). With burettes, it is almost always sufficient to clean the burette with tap water and then with distilled water.
If necessary, it can be soaked in a hot detergent solution for a while and then proceed as described above. Porcelain material, although it resists sudden changes in temperature well, should be avoided because it can break. To wash them, the same method can be followed as for glass.
If the glassware becomes cloudy or dirty or contains coagulated organic matter, it should be washed with stronger cleaning solutions, which are potentially dangerous as they contain acids or bases. Some special precipitates may need to be removed with nitric acid, aqua regia, or fuming sulfuric acid.
Fat removal
The best way to remove fat is to boil it in a mild solution of soda ash. We can use Acetone or any other grease solvent. Strong alkalis should not be used. We can remove Silicone grease by soaking the stopper or barrel in warm decahydronaphthalene for 2 hours.
It is also possible to remove grease from ground joints by rubbing with a paper towel dipped in acetone or any other suitable solvent. Use a fume hood to minimize exposure to vapors.
Rinse and drain, remove grease from glassware with acetone, or use fuming sulfuric acid for 30 minutes. Be sure to rinse the material until all cleaning agents are removed.
Rinsing of lab ware
It is essential to remove any remaining soap, detergent, or other cleaning liquid from the glassware before using it again. This is especially important with detergent, as slight traces of detergent can interfere with serological and cell culture applications.
After cleaning, rinse glass parts under running water. When rinsing test tubes, graduated tubes, flasks, and other similar containers under running water, allow the water to soak in and cover the part for a short time, then partially fill each item with water, shake vigorously, and empty at least six times.
The best way to rinse pipettes and burettes is by connecting a rubber tube to the faucet and then connecting the end of the pipettes or burettes to a hose, allowing the water to circulate through them. If the tap water is very hard, we recommend to use a deionizer or reverse osmosis system beforehand. Next, rinse the glassware in a large sink with high purity or distilled water.
To finish, rinse each utensil with high purity water. To conserve water, use a five-gallon (19 liters) drum as a reservoir. Store it on a shelf near the cleaning area. Connect a siphon and use it to replenish the reservoir with used distilled water.
Drying of laboratory material
Once the laboratory material is already clean, and sterilize, it must be adequately needs protection to prevent exposure to the environment or other factors that could dirty the material again.
Instruments and materials can lose their sterility if there is any type of rupture in them if the packaging material becomes wet or breaks (even very little), or if the storage area reaches excess temperature or humidity.
To ensure that the protected material keeps its sterility, it is essential to keep it clean, dry, and free of dust, dirt, or insects, as well as to control the temperature and humidity with the equipment.
Test tubes, culture tubes, and flasks, and hang other glassware on wooden clothespins to dry, or placed face down in racks to air dry.
Another alternative is to place them in buckets and dry them in the oven. The drying temperature must not exceed 140°C. (Avoid directly heating empty glassware for volumetric measurements. To dry the items, they should be at temperatures not exceeding 80°C or 90°C.)
Before placing glassware in the pan, line the bottom of the pan with a clean folded towel or clean cloth. This prevents the mouth of the tubes from getting dirty.
Allow burettes, pipettes, and cylinders to dry in an upright position on a folded towel. Protect glassware from dust. To do this, we recommend placing a cotton or cork stopper, or tape the mouth of the container with heavy paper, or placing the glassware in a dust-free cabinet.
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Glassware storage
To store, and place items on specially designed shelves. Make sure they are not in contact with each other to avoid unintentional mechanical damage. Do not place glass items over the edge of the shelves.
Do not store alkaline liquids in burettes or volumetric flasks.
Sterile material can maintain this condition. We recommend constantly rotating the materials to always have those that are close to expiration on hand and sterilize those that have recently been in the back, and use back labels for this. Dates of disinfection and sterilization will help to keep better control.