Introduction of materials into a glovebox

General procedure

Introducing items into the glovebox requires properly exchanging the atmosphere in and around the items using an antechamber that is attached to the glovebox. Make sure that the inside of any closed objects is properly treated, e.g., through exchanging the atmosphere in flame-drying cycles. If you need support with this, see this article in the “Schlenk Line Survival Guide”.

Before opening the antechamber, it MUST be closed towards the glovebox. Otherwise you’ll introduce huge quantities of air.

A general procedure is:

1. Check that the antechamber is filled, that it is closed to the inside of the glovebox, and that the gas/vacuum valve is closed. Then open the chamcber on the outside.
2. Place your items in the antechamber. You will often have a tray that you can pull out for easy loading.
3. Close the antechamber carefully. Forcefully closing the lid can damage it.
4. Evacuate the antechamber for 3 min. Check if you want to extend these cycles when introducing heavy loads.
5. Fill the antechamber with to about 800 mbar.
6. Repeat steps 4 & 5 twice more.
7. Completely fill the antechamber with inert gas.
8. You can now open the antechamber on the inside of the glovebox.

You can also evacuate things overnight, if you leave the antechamber on evacuation overnight instead.

Considerations regarding different types of materials

Introduction of porous materials

Porous materials (e.g. gloves or paper towels) should be evacuated in the antechamber overnight. For additional drying, the materials can be pre-dried in an oven to remove water before evacuating. Do NOT pre-dry materials that become brittle in the oven (e.g. gloves).

Introduction of glassware

Glassware (e.g. glass pipettes, NMR tubes) should be pre-dried in an oven at > 120 °C for at least 2 h or through flame-drying before evacuating in the antechamber following the general procedure.

Introduction of plastic & metal

Plastic and metal does not require pre-drying and can be introduced following the general procedure. If not needed immediately or if introducing larger amounts of it (e.g. a full package of one-use spatulas), evacuation overnight is advised, but not strictly necessary.

Introduction of solid chemicals

Solids can be introduced in two ways, depending on the packaging.

A. If a solid is stored under proper inert gas (e.g. an ordered, air-sensitive chemical that was shipped in a sealed, inert-gas-flushed bottle), you can simply place the storage bottle in the antechamber and follow the general procedure.

You can also introduce materials using your own flasks and containers. But make sure that all containers have been properly treated before use and that their content is dry and degassed.

B. If your solid is not stored under proper inert gas (e.g. a non-air-sensitive chemical that you need to use in the glovebox for a reaction), you need to open the storage bottle in a way that keeps gas flow intact without the risk of your solid getting thrown in the air and out of the bottle. An easy way to achieve this is by placing a small piece of paper towel between the lid and the storage bottle and loosely screwing the lid onto the bottle. Then, you can place the storage bottle in the antechamber and follow the general procedure.

Be careful to never introduce materials that can sublime at room temperature following method B. If you need to introduce these materials into the box, fill the substance in a properly schlenked container that can be closed and introduce the material following method A.

Introduction of liquid chemicals

Liquids can be introduced in three ways, depending on the amount of liquid introduced and their packaging.

A. If the liquid is stored under argon (e.g. a commercial, air-sensitive chemical that was shipped in a sealed, inert-gas-flushed bottle) you can simply place the storage bottle in the antechamber and follow the general procedure.

Be aware of the stability of the packaging under vacuum. Do not introduce items that you suspect may break under argon, which includes glassware with thin glass or with sharp edges. Adding an open outer packaging such as a metal can with loose lid can act as additional safety measure to contain spill areas in case of breakages.

B. Small amounts of liquid can be introduced in a syringe. If your do not use syringes that have locking mechanisms holding the needle in place, use paraffin film or electrical tape to fix the needled to the syringe as additional safety measure. Fill the syringe with the required amount of your liquid without a protective gas pocket. Pinch the needle into a rubber stopper to close it off to the atmosphere. You can introduce the whole syringe now according to the general procedure. Remember to bring your needle cover with you if required.

C. Larger amounts of liquid should be introduced in proper glassware. The glassware should have been properly dried before filling it with your liquid. If you cannot reduce the pressure due to safety, prize, or other considerations, the use of pressure-safe containers such as teflon screw-capped Schlenk flasks is recommended. For non-volatiles, carefully reduce the pressure inside of your glassware at the Schlenk manifold to about 100 mbar. For volatiles, you can carefully approach the boiling point and close your flask as soon as you see the development of gas bubbles.

Make sure to use strong clamps when introducing liquids. The cap can be lifted in the chamber under vacuum, particularly when a weak clamp is combined with non pressurised flask. This can lead to secondary glassware damage, contamination of your liquid and your antechamber, and serious hazards.

Introduction of solvents (if allowed)

Bulk solvents should be carefully dried and degassed before their introduction. Impure solvents can lead to problems in any chemistry using them. Due to the large amounts of introduced solvents, significant pollution can be caused to the glovebox atmosphere.

Ensure that your solvents are compatible with the local filters, catalysts, and the chemistry of other users. Significant amounts of solvents will be introduced to the gas phase when working with them in the glovebox.

Typically, this entails drying the solvent with a drying agent, potentially distilling and/or degassing it, and storing it over molecular sieves. For many applications, molecular sieves are sufficient drying agents which allows simply storing solvents on an appropriate amount of sieves for 48 h prior to their introduction to the glovebox. Consult appropriate literature for drying procedure of a specific solvent (e.g., in the book “Purification of Laboratory Chemicals”). The degassing of solvents has also been elaborated elsewhere (e.g., freeze-pump-thaw in the “Schlenk Line Survival Guide”).

After a solvent was dried and degassed, it can be introduced into the glovebox according to a procedure described in the “liquid chemicals” section.