What is the recommended procedure for cleaning lab glassware?

Document ID

Document ID TE3656

Published Date

Published Date 06/09/2018
Question
What is the recommended procedure for cleaning lab glassware?
Summary
Procedure for cleaning glassware
Answer
Below are instructions from Kimble Kontes® who  is the manufacture of many of the glassware products that Hach sells.

Care should be exercised when using most cleaning solutions as they can cause skin irritations or severe burns on contact. Dilute solutions become concentrated as the water evaporates; therefore, always flush the exposed area immediately with large quantities of water. The list of methods given here is by no means complete, but offers a fairly wide variety and should cover all the usual contaminants, as well as the more important special cases. Frequently it is desirable to give glassware a preliminary rinse or soak with organic solvent to remove grease, followed by a water rinse. The rinsing with water must be done thoroughly if acid will be used later to clean the glassware. Unless autoclaving is necessary, glassware should be cleaned as soon as possible after use to avoid setting and caking of residues. Pipets, for example, may be placed in a convenient jar containing a weak antiseptic solution, immediately after use. Autoclaving is necessary to disinfect glassware that may have been used to contain potentially dangerous biological fluids. There is a wide variety of cleaning agents available that will remove surface contaminants such as silicone and other organic and biological residues, blood residues and other contaminants that may interfere with trace analyses. These cleaners are available in biodegradable, phosphate-free and chromium-free formulations if desired and can be obtained from laboratory supply houses.
NOTE: If wiping or other mechanical cleaning action in necessary, it should be done gently using non-abrasive cleaners and wiping materials. The use of abrasive materials will damage the glass surface, degrading its inherent strength.

There are some specific contaminants that may require specialized cleaning methods, and some are given here:
1. Permanganate stains. Use a mixture of equal volume of 3% sulfuric acid and 3% hydrogen peroxide.
2. Iron stains. Use a solution containing on part hydrochloric acid and one part water.
3. Bacteriological material. Glassware should be soaked in a suitable disinfectant solution or steam autoclaved followed by cleaning with a suitable agent.
CAUTIONS: Before using any cleaning solution, refer to its Material Safety Data Sheet for precautions to be observed during use. Some of the cleaning materials used may leave trace residue unless rinsing process is carried out thoroughly. While such traces may not be harmful if the object of cleaning is to prepare the glassware for calibration, they can give trouble in certain laboratory operations. When glassware is to be calibrated, the final rinsings must be distilled water. If an article is to be dried after cleaning, as is necessary for all vessels marked “To Contain”, ethyl alcohol or acetone (American Chemical Society Specification) may be used. Drying may be hastened by blowing clean, dry air into the vessel (or sucking the air through the vessel). Efficient air filters must be provided to remove any particles  of oil or dirt from compressed air. Drying should be done in a fume hood.
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