Handling glass ware

If you break something, let a technician know.

Introduction

The Cohen laboratories are organised in such a way that they cannot work if everyone doesn’t work together.

Clean glassware is essential in (geo)chemistry. In the Cohen labs we define ‘clean’ by procedure and assume that all glassware has gone through a minimum cleaning procedure to ensure a basic level of physical and chemical cleanliness. This procedure makes the glassware suitable for most of the work we carry out in Cohen. This system relies on trust and makes it the responsibility of every user to clean their glassware after use.

In a few specific cases this minimum procedure may not be enough leave your glassware ‘fit for purpose’. Examples include, low level trace metal work and organic chemistry. In these case you may have to develop your own cleaning method to ensure that small impurities do not massively affect your results. If you are not sure whether the minimum cleaning procedure is sufficient for your work please ask a technician.

Appropriate PPE should be worn for all glassware cleaning operations.

Training is required for handling concentrated acids (including making acids baths).

Key cleaning tips

• Clean your glassware as soon as possible after use. The longer you leave it the more difficult it becomes.
• Be aware of what was in the glassware before you start cleaning it. It could have been toxic or corrosive or it might not react well with water. Make sure glassware has been completely drained to an appropriate location. Be careful not to splash rinse water.
• Remove all stopcocks and stoppers before cleaning. Degrease any ground glass joints by wiping them with a paper towel soaked in a small amount of ethanol, isopropanol or acetone.
• Avoid using detergents as many lab users are measuring phosphate and chlorine which may be present in the detergent.
• Most new glassware is slightly alkaline in reaction. For precision chemical tests, new glassware should be soaked several hours in acid water (a 1% solution of hydrochloric or nitric acid) before washing.
• Water will sheet cleanly off clean glass. If water does not sheet off (i.e. it forms droplets/ rivulets) the glass may need further cleaning.

Standard procedures - General glassware (not volumetric)

All glassware should be cleaned to a minimum standard after use so that the next person to come along knows it is clean and can use it. This is the user’s responsibility.

Minimum cleaning level for general glassware

1. Rinse with DI water
2. Use a bottle brush or cloth to remove any obvious dirt
3. Place in 10% acid bath (HCl or Nitric) overnight
4. Remove and rinse 3-5 times with DI water
5. Leave to dry either on rack or in a drying oven
6. Put back into cupboard

Alternative cleaning methods for general glassware

If you require glassware to be cleaned in a certain way for your specific application please ensure you keep that glassware separate and clearly labelled. If you require separate storage please let a technician know.

Cleaning volumetric glassware

Volumetric glassware includes burets, pipets and volumetric flasks. I am going to focus on volumetric flasks as we don’t use many glass burets or pipets. Solutions should not be stored long term in volumetric glassware they should be transferred to an alternative container. Volumetric flasks should not be left filled with DI water for long periods of time. Volumetric glassware should never be dried in an oven.

Minimum cleaning level for volumetric flasks

1. Rinse with DI water
2. Very carefully use a bottle brush or cloth to remove any obvious dirt
3. Rinse very thoroughly 5 times with DI water
4. Leave to dry on side (not in oven) – use a test tube rack to invert bottles
5. Replace stopper and return to cupboard/shelf

Alternative cleaning methods for volumetric glassware

If you require your volumetric glassware to be cleaned in a certain way for your specific application please ensure you keep that glassware separate and clearly labelled. If you require separate storage please let a technician know.

If you are using volumetric glassware the presence of impurities (particularly grease) may alter the meniscus of the glassware and reduce the accuracy of your measurements. However, volumetric glassware should not be cleaned with strong base or acid.