Standard Operating Procedures s5

These safety training resources, prepared solely for the use of the Regents of the University of California, were provided by a variety of sources. It is your responsibility to customize the information to match your specific operations. Neither the University of California nor any of its employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the University of California, and shall not be used for advertising or product endorsement purposes. Standard Operating Procedure ______Read the EH&S Standard Operating Procedures Fact Sheet before filling out this form. Print out the completed SOP and keep a readily accessible hard copy in the lab (also keeping an electronic copy is highly recommended). ______

Date: SOP Title: Using Aqua Regia to remove gold Principal Investigator: Room and Building: Lab Phone Number:

Section 1 – Process Aqua regia is used to remove gold from substrates. It is a 1:3 mixture of concentrated nitric acid and concentrated hydrochloric acid and is extremely corrosive. Gold coated atomic force microscope cantilevers are immersed in a 40 ml solution of aqua regia for a few seconds and then are rinsed in DI water.

Section 2 – Hazardous Chemicals Nitric acid Hydrochloric acid

Section 3 – Potential Hazards HIGHLY CORROSIVE STRONG OXIDIZER - May ignite flammable/combustible materials: DO NOT mix with ORGANIC solvents OVERPRESSURE EXPLOSION HAZARD – DO NOT confine while reaction continues to out-gas INHALATION HAZARD – perform work inside a fume hood Review MSDS before using material, Review EH&S corrosive fact sheet. Section 4 – Approvals Required Use of aqua regia must be approved by the Principal Investigator or Lab Safety Officer

Section 5 – Designated Area Inside chemical fume hood

Section 6 – Special Handling Procedures and Storage Requirements Aqua regia waste must be picked up by EH&S. In the mean time, store waste in own glass bottle with secondary containment in acid chemical fume hood with the cap LOOSELY on top. The solution will give off gas and could build up pressure if cap were sealed tightly. When waste container is full dispose of through EH&S.

Whenever handling aqua regia, only use glass containers (preferably Pyrex). Containers used during the experiment must be very clearly labeled and a warning sign, visible by any user working under the flow hood, must be posted at all time to indicate that the solutions contains aqua regia mixture.

Mix the solution in the fume hood with the sash between you and the solution. Wear the full protection.

Section 7 – Personal Protective Equipment The handling of aqua regia solutions requires special protection equipment in addition to the regular Clean Room protection outfit (safety goggles, lab coat, gloves).

The additional protective equipment include: a full face shield, heavy duty rubber gloves (regular disposable Nitrile gloves will not provide sufficient protection), as well as an acid apron to wear on top of the lab coat.

As a reminder, open-toed shoes are not allowed when working in the lab. Feet and legs must be covered.

Section 8 – Engineering/Ventilation Controls Make sure sash is down to create sufficient ventilation. Know that emergency eyewash is working properly and that it is accessible. Do not dip gloved hands into solution use tools (i.e.. forceps) Section 9 – Spill and Accident Procedures In case of large exposure, the victim should be removed from the contaminated area, placed under a safety shower while emergency personal is contacted(911)

All contaminated clothing should be removed immediately with appropriate gloves and safely discarded.

In case of contact with the skin, the affected area must be immediately rinsed with large amounts of water for at least 15min.

In case of contact with the eye, irrigate the eye for at least 30 minutes, keeping the eyelids apart and away from eyeballs during irrigation. Call 911, Place ice pack on eyes until reaching emergency room.

In case of inhalation, it may irritate the respiratory tract. Conscious persons should be assisted to an area with fresh, uncontaminated air. Seek medical attention in the event of respiratory irritation, cough, or tightness in the chest. Symptoms may be delayed. Section 10 – Waste Disposal The primary hazard from storage of aqua regia etch waste is the potential for gas generation and over pressurization of the container when the solution is still hot. If you store a hot solution in a tight container, it will explode and spray acid!

Therefore prior to store the aqua regia solution, it must be left in an open container in order to cool down for several hours (overnight). It is your responsibility to make sure that the open container is very clearly labeled and left in a safe area for overnight cool down.

Once cooled down, the solution can be transferred into a closed glass container for waste storage. The container must be very clearly labeled with the solution name and composition and must include VERY VISIBLE warning signs not to add any other types of chemicals.

Never add organic solvents to strong acids.

Section 11 - Decontamination Rinse contaminated beakers and glassware with lots of water. Carefully pour the aqua regia solution into the aqua regia waste beaker in the aqua regia hood. Clean area with soap and water, test area with pH paper, until surfaces are almost neutral.

Section 12 – Process Steps Process Steps Safety Measures 1. Place on glass slide. 2. In hood, pour 30ml hydrochloric acid in beaker. 3. Add 10ml nitric acid & swirl gently Will fume. Keep at least 6” in from edge of fume hood 4. Take levers on slide in one hand, & using tweezers in other hand to lower levers into beaker (watch orientation – don’t smash levers on bottom) & tap tweezers between levers. 5. Let sit for the required time (room temp). Put sign up on hood. “Agua Regia in Use” 6. Rinse tweezers in lots of water. 7. Rinse & dispose of slide. 8. Fill 2 1000ml beakers with ~800ml DI water and one 100ml beaker with ~100ml DI water. Pickup chip (make sure you have a good grip!) & swirl gently for ~15 seconds in each of the large beakers. Then place in smaller beaker. 9. Repeat step 9 for all chips. 10. Dry on cleaned slide. Tap gently (non lever side!) to remove water and then leave under scope with light on. 11. Check levers to see if chip is usable (all there? Cracked?). Store in dessicator. 12. Clean up: Clear out sink. Rinse the “rinse DO NOT tighten the cap! beakers” with lots of water. Carefully pour the aqua regia solution into the aqua regia waste beaker in the chemical hood. Transfer to waste bottle when sure the reaction is done. Cap bottle before pick-up by EH&S, consider use of a vented cap.

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