• It is also important to keep laboratory glassware clean. Glassware should be cleaned with laboratory designed detergents (an example would be Tergajet or Solujet labware cleaning agents, or the Nalgene L900 cleaner). Clean as soon as possible to decrease the amount of buildup which makes cleaning more difficult. When using brushes, be careful to avoid damaging the surface of the glass product.

    After washing glassware, be sure to rinse thoroughly to prevent contamination. It is not advised to towel dry, instead allow glassware to air dry. Inspect the surface to ensure it is free from any defects or particulate matter. Any glassware with chips, cracks or scratches should be removed from service and disposed of properly.

    Glassware that is jammed together or frozen should be carefully released by someone wearing appropriate protective equipment such as cut-resistant gloves and goggles to prevent injuries. Two examples of frozen glassware are nested glassware that is stuck together and immovable stoppers.

    Even the most carefully executed experiment can give erroneous results if dirty glassware is bought to use. If the glassware that is used for measuring liquids is contaminated with grease and other materials, it prevents the glass from being uniformly wetted. This in turn will affect the volume of liquid delivered and the amount of residue adhering to the walls of the container. Likewise, presence of impurities in glass labware can distort the meniscus and can prevent one from getting the correct results out of the science lab experiment.

    Keeping the laboratory glassware physically neat and clean, free of grease, and bacteria is therefore of the utmost importance.

    To keep your glass labware neat and clean, you must wash it immediately after use. Put glassware in water if you can not clean it immediately otherwise the residue will stick to the labware and it would get difficult to remove it.

    For washing the glass labware, make use of soap, detergent, or cleaning powder. Try to use soap and cleaning powder without any abrasives as it can scratch the glass. However, for glassware that is too dirty, you can make use of cleaning powder with mild abrasive action to get good cleaning results. Chromic acid solution is quite effective in cleaning unduly clouded or dirty glassware. For scrubbing the glassware thoroughly, you must use a brush.

    After cleaning, rinse the glassware with tap water. Allow the water to run into and over the glassware and then fill each piece with water. Fill test tubes, flasks, and other glassware with water and shake and empty them. Do this for at least 5-6 times to clean the glassware properly. For cleaning contaminated glassware, you will have to sterilize them too.

    Washed labware must either be placed in a basket with their mouth downwards for allowing them to dry completely or they should be made to dry in an oven. You can also hang test tubes, flasks, and other labware on wooden pegs for drying them out. Stand dry cylinders, burets, and pipets on a towel for drying them properly.

    Place clean glassware in a cabinet to protect it from dust. You can also make use of cotton, or cork, or can tape a piece of paper on the mouth of the glassware to prevent dirt and dust from entering the glassware. Keep washed, cleaned, and sterilised glassware pieces in special racks and at a distance to avoid any breakage.

    With proper care and maintenance you can not only increase the life of your labware, but can also enhance your lab safety.

     

    Cleaning laboratory glassware isn't as simple as washing the dishes. Here's how to wash your glassware so that you won't ruin your chemical solution or laboratory experiment.

    Cleaning Basics

    It's generally easier to clean glassware if you do it right away. When detergent is used, it's usually one designed for lab glassware, such as Liquinox or Alconox. These detergents are preferable to any dishwashing detergent you might use on dishes at home.

    Much of the time, detergent and tap water are neither required nor desirable. You can rinse the glassware with the proper solvent, then finish up with a couple of rinses with distilled water, followed by final rinses with deionized water.

    How to Wash Out Common Lab Chemicals

    • Water Soluble Solutions (e.g., sodium chloride or sucrose solutions)
      Rinse 3-4 times with deionized water then put the glassware away.
    • Water Insoluble Solutions (e.g., solutions in hexane or chloroform)
      Rinse 2-3 times with ethanol or acetone, rinse 3-4 times with deionized water, then put the glassware away. In some situations other solvents need to be used for the initial rinse.
    • Strong Acids (e.g., concentrated HCl or H2SO4)
      Under the fume hood, carefully rinse the glassware with copious volumes of tap water. Rinse 3-4 times with deionized water, then put the glassware away.
    • Strong Bases (e.g., 6M NaOH or concentrated NH4OH)
      Under the fume hood, carefully rinse the glassware with copious volumes of tap water. Rinse 3-4 times with deionized water, then put the glassware away.
    • Weak Acids(e.g., acetic acid solutions or dilutions of strong acids such as 0.1M or 1M HCl or H2SO4)
      Rinse 3-4 times with deionized water before putting the glassware away.
    • Weak Bases (e.g., 0.1M and 1M NaOH and NH4OH)
      Rinse thoroughly with tap water to remove the base, then rinse 3-4 times with deionized water before putting the glassware away.

    Washing Special Glassware

    • Glassware Used for Organic Chemistry
      Rinse the glassware with the appropriate solvent. Use deionized water for water-soluble contents. Use ethanol for ethanol-soluble contents, followed by rinses in deionized water. Rinse with other solvents as needed, followed by ethanol and finally deionized water. If the glassware requires scrubbing, scrub with a brush using hot soapy water, rinse thoroughly with tap water, followed by rinses with deionized water.
    • Burets
      Wash with hot soapy water, rinse thoroughly with tap water, then rinse 3-4 times with deionized water. Be sure the final rinses sheet off of the glass. Burets need to be thoroughly clean to be used for quantitative lab work.
    • Pipets and Volumetric Flasks
      In some cases, you may need to soak the glassware overnight in soapy water. Clean pipets and volumetric flasks using warm soapy water. The glassware may require scrubbing with a brush. Rinse with tap water followed by 3-4 rinses with deionized water.

    Drying or Not Drying Glassware

    • Not Drying
      It is inadvisable to dry glassware with a paper towel or forced air since this can introduce fibers or impurities that can contaminate the solution. Normally you can allow glassware to air dry on the shelf. Otherwise, if you are adding water to the glassware, it is fine to leave it wet (unless it will affect the concentration of the final solution). If the solvent will be ether, you can rinse the glassware with ethanol or acetone to remove the water, then rinse with the final solution to remove the alcohol or acetone.
    • Rinsing with Reagent
      If water will affect the concentration of the final solution, triple rinse the glassware with the solution.
    • Drying Glassware
      If glassware is to be used immediately after washing and must be dry, rinse it 2-3 times with acetone. This will remove any water and will evaporate quickly. While it's not a great idea to blow air into glassware to dry it, sometimes you can apply a vacuum to evaporate the solvent.

    Additional Notes

    • Remove stoppers and stopcocks when they are not in use. Otherwise they may 'freeze' in place.
    • You can degrease ground glass joints by wiping them with a lint-free towel soaked with ether or acetone. Wear gloves and avoid breathing the fumes.
    • The deionized water rinse should form a smooth sheet when poured through clean glassware. If this sheeting action is not seen, more aggressive cleaning methods may be needed.

     

  • Disposing of Laboratory Glassware
    Check glassware for chips, cracks or other faults before each use. Any faults will make the glassware more prone to break during use, which could be hazardous. Discard and replace any faulty glassware.

    Defective glassware should be disposed of properly. Broken glassware should not be discarded with the regular trash. It should be placed in the designated broken glass container as provided by the instructor. Do not attempt to pick up broken glass without using cut-resistant gloves and/or a dust pan and broom.