Cleaning Glassware in the Laboratory

In the lab, it is important to maintain the cleanliness and hygiene of all glassware. Incorrect washing and sterilising could lead to incorrect results, affecting hours of work.

Our guide will suggest suitable methods to clean glassware.

Health and Safety Precautions

It is essential to wear eye protection, and for some chemicals, you must wear other types of Personal Protective Equipment (PPE), such as gloves. It is also important to check regularly that all PPE equipment is in good condition and suitable for use.

The General Procedure

Firstly, make sure you are cleaning your glassware promptly after use. Allowing dirty glassware to sit for a long period of time may be harder to clean. Also, consider prioritising glassware which may take a longer amount of time to wash.

Degrease your glassware and cover every joint by wiping them with a paper towel soaked in a small amount of ether or acetone. Next place the glassware in a warm aqueous solution of detergent and let it sit for around 8 mins, make sure to use a detergent that isn’t abrasive. Scrub with a brush that is in good shape as scratches may cause the glassware to break.

Finally rinse with tap water and then with Deionised Water.

Cleaning Pipettes

Making sure to soak pipettes is essential, prepare a container with water preferably inside a cylinder with a high enough water level to submerge them. Make sure to not drop them as you may break or chip the pipette. Make sure to soak the pipettes for several hours in the water.

Dealing with Grease

Boiling the glassware in a weak solution of sodium carbonate is the best method of removing grease.

Drain and wash the glassware with acetone.

Specific Stains

1. For permanganate stains, use a mixture of equal parts 3% Sulphuric Acid and 3% Hydrogen Peroxide.
2. For iron stains, use a solution containing one-part Hydrochloric Acid and one part water.

Rinsing

After you have completed any of the methods above, rinse the glassware with tap water allow the water to run into it for a short time and fill it with water, perform this at least six times.

Dry burettes, cylinders, and pipettes by standing them up on a towel and to protect the glassware from any dust make sure to plug them with cotton or corking.