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Operating the Glovebox

Overview

Robert M Rioux, Ajay Sathe, Zhifeng Chen, Pennsylvania State University, University Park, PA

A glovebox is an isolated enclosure that is designed to maintain an inert atmosphere. The manipulation of chemicals or apparatus is done via the use of gloves, which allow operation while still maintaining an inert atmosphere. A positive pressure is utilized to compensate for any passive leaks. Objects can be transferred in and out of the box using an antechamber that acts as an airlock between the box and the outside atmosphere1. A glovebox can have multiple pair(s) of gloves associated with it depending on the size of the box.

Principles

The glove box works by containing a closed circulation loop which utilizes a blower, plumbing, and a purifier to maintain H2O and O2 levels lower than 1 ppm. The atmosphere is purified by air circulation through a catalyst bed to remove moisture and oxygen. The catalysts include copper based particles to remove O2 and molecular sieves to remove H2O. After 3-6 months usage, the catalysts need to be regenerated by isolating the catalysts from the glovebox and exposing them under 5% H2 in N2 and heating to reduce the formed copper oxide to metallic copper. Certain volatile chemicals such as halogenated compounds and strongly coordinating species (thiols) should be excluded from the glovebox because they have a high propensity to poison the catalysts. Instead, experiments involving these types of chemicals should be conducted in a Schlenk line.

Initial training and proper operation are important for the safe use of the glovebox. All chemicals must be degassed and dried before being placed into the glovebox. Glass vessels or flasks must be evacuated before placement in the antechamber to avoid explosion due to the pressure difference. Sharps should be carefully handled and avoided if possible when working with the glovebox to avoid possible damage to the glove. Furthermore, secondary nitrile gloves must be worn to protect the glove when working with solvents. Aqueous solutions, alcohols, and acetone should not be used in the glovebox in order to ensure the glovebox environment is free of H2O and O2, which may help protect the glove over its lifetime. Compared to the glovebox, there are fewer requirements regarding the suitability of samples for the Schlenk line. However, there are other safety concerns when using schlenk line, such as ensuring glassware is not cracked, the possibility of over-pressurization of the glass schlenk line, and the use of liquid nitrogen in the pump trap could lead to the possible condensation of oxygen, if a leak exists in the schlenk line.

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Procedure

1. Transferring Objects into the Glovebox

  1. Make sure both doors are closed (this should be the default position). If the chamber is under vacuum, fill it with nitrogen by turning the valve to fill.
  2. Open the outer door, and transfer the object in the chamber. Slide the object as deep as possible, which makes it easier to reach it from inside the glovebox. Close the door isolating the antechamber from the ambient environment. DO NOT over tighten the door, go only a quarter-turn further.
  3. Once the doors are closed, turn the valve to evacuate the chamber, and wait until the pressure is at an acceptable vacuum level. Then fill the chamber with nitrogen, by turning the valve to refill. Repeat this cycle at least 3 times.
  4. Once the purging and evacuation cycles are complete, fill the chamber with nitrogen, and then open the inner door to the glovebox. Remove the object from the antechamber and place in a safe location in the glove box. Promptly close the door to the antechamber.
  5. With the doors closed, turn the valve on the antechamber to vacuum, and leave it there. This is the default position of the antechamber when not in use.

2. Transferring Objects Out of the Glovebox

  1. Make sure the antechamber is filled with nitrogen. If you are unsure about the state of the chamber, evacuate and refill the chamber with nitrogen at least 3 times.
  2. Open the inner door, and transfer the object into the chamber. If the object includes chemicals, make sure it is properly sealed. Then close the inner door to the antechamber.
  3. Open the outer door and remove the object(s).
  4. Close the outer door and turn the valve to evacuate. The default condition for the antechamber is to be under vacuum.

3. Chemicals and Apparatus

  1. Make sure all of the apparatuses that you transfer into the glovebox are dry.
  2. Any chemical that is taken in the glove box must be dry and deoxygenated. It is best to use DriSolv solvents. If these are not available, it would be preferred to use solvent bottles which have not been opened outside of the glovebox.
  3. Take only the required amount of chemicals into the glovebox, full reagent bottles MUST NOT be taken in (unless the reagent has to be permanently stored in the box).
  4. Use 20-mL vials to transfer solids and non-volatile liquids. Wrap the top of the vials with lab wipes and use a rubber band to hold the wipe in place. This allows the air above the solid/liquid to be evacuated.
  5. While transferring volatile liquids, use Teflon stoppered flasks.
  6. Be extremely careful while using needles and blades in the glove box. The gloves are extremely delicate, and any puncture can compromise the atmosphere in the box.
  7. Once you have finished your work, take out all the apparatuses promptly and clean the area.
  8. Store any chemicals that have been synthesized in an appropriate location within the box and label it appropriately.
  9. Let the person in charge of the box know if any of the glovebox-dedicated consumables are running low.

4. Solvents

  1. While taking in solvents, make sure to use the Teflon-stoppered round-bottom flasks, and only use dry deoxygenated solvents from the solvent stills or as ordered from chemical suppliers.
  2. All the solvent bottles stored in the box should be capped all times.
  3. Solvent vapors can damage the gloves, and hence any solvent spills must be promptly wiped with lab wipes, and then removed since volatile solvent vapors will remain.
  4. Place the solvent bottles back in the appropriate location once you have finished using them.

5. Waste Disposal

  1. Dispose of the waste in properly labeled waste beakers.
  2. Recap the needles after use before disposing of them.
  3. If the waste container is full after you use it, take it out of the box, and dispose of it properly in the lab waste, and promptly replace the waste container in the glovebox.
  4. Clean up any spills on the glove box floor and dispose waste in the misc. waste.
  5. The liquid waste bottle MUST be capped at all times.

6. General Tips

  1. Do not insert/remove your hands from the gloves quickly. Doing so quickly will cause a sudden pressure change in the box, which can lead to ambient air from the external environment accessing the glovebox through any micro pores on the gloves.
  2. Be extremely careful while using needles and blades in the glove box. The gloves are extremely delicate, and any puncture can compromise the atmosphere in the box.
  3. Make sure the chambers are always left under vacuum after use.
  4. Shut off the blower using the main screen when handling amines, phosphines, or any other volatiles, since they can damage the catalysts.
  5. Keep a logbook of all glovebox activity including maintenance performed on the glovebox.
  6. Conduct maintenance (vacuum pump oil change, regeneration of purification system) on a regular schedule.

A glove box is an important device used in research laboratories and industry to work with air- and water sensitive compounds, and radioactive and biohazardous materials.

A glove box provides an isolated and enclosed environment with an inert atmosphere.

The gloves are used to work with the chemicals and instruments inside the box allowing for handling of very sensitive materials, which is not always possible with a Schlenk line.

This video will illustrate how a glove box works and how to safely manage the use of chemicals, solvents, and waste inside the box.

The inert atmosphere inside a glove box is established by a closed circulating system using a blower, pluming, and a gas purification system. The purifier ensures that the water and oxygen levels are kept below 1 ppm by circulating the atmosphere. The copper containing catalyst present in the purifier converts oxygen to copper oxide. While molecular sieves are used to absorb and remove the water molecules.

Furthermore, vacuum pumps and inert gas ensure that no contamination is introduced when passing chemicals or instruments through the antechamber into the glove box.

To introduce materials and objects into the glove box, first check if both doors of the antechamber are closed. Fill the chamber with nitrogen by turning the valve to fill, if the chamber is initially under vacuum.

Open the outer door, and transfer the desired object in the chamber, making sure to slide the tray as deep as possible to facilitate easier reach from the inside of the glove box. Then close the outer antechamber door carefully and turn the valve to evacuate.

Wait until the pressure reaches an acceptable vacuum level and then turn the valve to refill, so the chamber will be purged with nitrogen to normal atmospheric pressure.

Wear cotton or nitrile gloves and enter the gloves of the glove box slowly. Be careful when inserting hands into the gloves, because a too sudden movement can cause a rapid pressure change leading to air leakage from outside inside the box through any micro pores. Also, wear nitrile gloves over the glove box gloves to protect them against solvents and chemicals.

Now open the inner door to the glove box and remove the objects from the antechamber and place them in a safe location in the glove box, then promptly close the door.

With both doors closed, turn the valve to vacuum, which is the default position of the antechamber when not in use.

Label and store any synthesized chemicals in an appropriate location within the glove box. Remove any other objects as soon as you are done and clean the area.

Always make sure that all chemicals and containers are properly sealed before the transfer. Make sure the antechamber is filled with nitrogen before ejecting your materials. If you are unsure, repeat the evacuation-purging cycle three times.

Open the inner door, place the objects inside the antechamber, and close the door. Then, open the outer door and remove your objects. Close the door and turn the valve to evacuate and leave it at this default condition.

Maintaining the glove box's inert atmosphere is essential for a safe working environment. Therefore special handling of chemicals, solvents, and equipment has to be assured.

Make sure to always transfer only dry objects and reagents into the glove box to maintain the inert atmosphere and low levels of oxygen and water.

Chemicals, including solvents, have to be dry and deoxygenated. Use a new bottle of the desired chemical to avoid chemicals containing a higher amount of contaminants absorbed from the air.

Certain volatile chemicals such as thiols, amines, or halogens can poison the catalyst making it less efficient. Therefore use a Schlenk line for compounds like these, if possible. Shut off the blower, if a glove box has to be used, to minimize catalyst poisoning.

Furthermore, avoid introducing aqueous solutions and alcohols into the glove box to maintain low levels of water and oxygen.

Use only the required amount of reagents and never transfer full reagent bottles into the glove box, unless these reagents will be permanently stored in the box. Vials can be used for the transfer of solids and non-volatile liquids inside the glove box.

All reagents need to undergo the evacuation-purging cycle, therefore wrap the top of the vials with lab wipes and secure with a rubber band.

Additionally, glass vessels need to be evacuated before insertion into the antechamber to prevent explosions due to the pressure difference. And sharp objects such as needles and razor blades should be handled with extra care to avoid puncturing the gloves of the glove box.

Once in the glove box, solvent and chemical bottles should always be capped and placed back in the appropriate location for storage. Spills must be promptly wiped off and absorbents such as lab wipes removed to avoid damage to the gloves from vapors.

Properly label all designated waste containers inside the glove box. Liquid waste bottles must be capped at all times and needles recapped after use before disposing of them, and in case of a spill any clean up material should be disposed in the solid waste.

If the waste container is full, transfer it out of the glove box and dispose of the waste appropriately in the laboratory waste. Replace the waste container in the glove box promptly.

Maintenance should be performed to ensure longevity of the glove box. Regularly change the vacuum pump oil, 5% hydrogen in nitrogen and heating to reduce the formed copper oxide.

Furthermore, make sure the chambers are always left under vacuum.

You've just watched JoVE's introduction to working with a glove box. You should now understand how a glove box operates, how to safely transfer objects inside and outside the box, and how to handle chemicals, solvents, and waste. Thanks for watching!

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Applications and Summary

Gloveboxes are essentially devices in the research laboratory for the manipulation of air- and water-sensitive chemicals that are not easily worked with on a Schlenk line. Gloveboxes are particularly useful for the transfer of chemicals into vessels that are incompatible with Schlenk line assemblies. The proper operation, good housekeeping, and maintenance of a laboratory glovebox ensure that sensitive experiments can be conducted without exposure to oxygen and water.

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References

  1. Ashby and R. D. Schwartz J. Chem. Educ., 1974, 51 (1), p 65
  2. Glovebox Use Guidelines, University of Houston, 2009.
  3. Standard Operating Procedures, Bartlett Group, University of Michigan, 2016.

Transcript

Tags

Glove Box Research Laboratories Industry Air-sensitive Compounds Water-sensitive Compounds Radioactive Materials Biohazardous Materials Isolated Environment Inert Atmosphere Gloves Schlenk Line Video Tutorial Chemicals Solvents Waste Management Circulating System Blower Plumbing Gas Purification System Purifier Water Levels Oxygen Levels Copper Oxide Catalyst Molecular Sieves Vacuum Pumps Antechamber Nitrogen Filling

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