UCSF Lab Standard Operating Procedure
Chemical Process, Name or Hazard Class:
Hydrofluoric Acid – HF
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Department:
Date SOP was written:
This lab specific SOP has been reviewed and approved by:
Principal Investigator Name:
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Type of SOP:
☐ Process
☐Hazardous Chemical
☐ Hazard Class
Describe Process, Hazardous Chemical or Hazard Class:
Hydrofluoric acid (HF) is a highly corrosive liquid and is a contact poison. It should be handled with
extreme care (i.e., beyond what is generally required to handle other mineral acids). Owing to its
low dissociation constant, HF as a neutral lipid-soluble molecule penetrates tissue more rapidly
than typical mineral acids. Because of the ability of hydrofluoric acid to penetrate tissue, poisoning
can occur readily through exposure of skin or eyes, or when inhaled or swallowed. Symptoms of
exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function,
meaning that burns may not initially be painful. Accidental exposures can go unnoticed, delaying
treatment and increasing the extent and seriousness of the injury. If not stored, handled and
disposed of properly, HF can pose a serious threat to the health and safety of laboratory personnel,
emergency responders and waste handlers. Hence, it is important to thoroughly understand the
properties of HF and follow all safety protocols to properly store and handle HF.
Uses: HF is used to etch glass. A 5% to 9% hydrofluoric acid gel is also commonly used to etch all
ceramic dental restorations to improve bonding. For similar reasons, dilute hydrofluoric acid is a
component of household rust stain remover and in car washes in "wheel cleaner" compounds.
Because of its ability to dissolve iron oxides as well as silica-based contaminants, hydrofluoric acid
is used in pre-commissioning boilers that produce high-pressure steam. Because of its ability to
dissolve oxides, hydrofluoric acid is useful for dissolving rock samples (usually powdered) prior to
analysis. The ability of hydrofluoric acid to dissolve metal oxides is the basis of several applications.
It removes oxide impurities from stainless steel, a process called ‘pickling’, and silicon wafers in the
semiconductor industry.
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In the lab, fluoride ions are also useful to examine the conductance properties of anion channels.
Hydrofluoric acid is a primary source of fluoride ions for making metal halide salts for use in anion
channel electrophysiology.
Physical & Chemical Properties/Definition of Chemical Group
CAS#: 7664-39-3
Class: Very toxic & Corrosive
Molecular Formula: HF
Form (physical state): Liquid
Color: Colorless
Boiling point: Not applicable
Potential Hazards/Toxicity
HF removes calcium from body in the affected area (Targets the bone)
Target Organs - Liver, Kidney
Potential Health Effects
Inhalation Toxic if inhaled. Material is extremely destructive to the tissue of the mucous
membranes and upper respiratory tract.
Skin May be fatal if absorbed through skin. Causes skin burns.
Eyes Causes eye burns. Causes severe eye burns.
Ingestion May be fatal if swallowed.
Engineering Controls
Work with HF solution in a certified chemical fume hood and the airflow monitor is within
acceptable limits. Insure sash height is positioned correctly at ~18 inches or less. Use the sash as a
splash shield.
Do not start nor continue an experiment if the fume hood is not working. Close the sash and contact
EH&S immediately.
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Respirator Protection
When a fume hood cannot be used, a half or full face respirator equipped with appropriate
cartridges is required. Lab personnel intending to use/wear a respirator mask must be trained and
fit-tested by EH&S.
Personal Protective Equipment (PPE)
Hand Protection
Heavy neoprene, butyl or silver shield over nitrile gloves is highly recommended for large
quantities, double nitrile gloves are required for smaller amounts. Gloves must be inspected prior
to each use. Use proper glove removal technique (without touching outer surface of the gloves) to
avoid skin contact with HF on the contaminated gloves. Dispose of inner nitrile gloves after use as
hazardous waste. *Heavier outer gloves (neoprene, butyl, silver shield can be reused carefully (i.e.,
without touching the outer surface of the gloves). Wash hands thoroughly with warm water and
soap.
Apron and arm covering are recommended for splash protection.
NOTE: Consult with your preferred glove manufacturer to ensure that the gloves you plan on using
are compatible with Hydrofluoric acid.
Refer to glove selection chart from the links below:
UCSF Glove Selection Guide
Ansell Chemical Resistance Guide
Microflex Chemical Resistance Guide
North Chemical Resistance Guide
http://www.allsafetyproducts.biz/page/glove-selection-chart
Eye Protection
Tightly fitting safety goggles & face shield (ANSI approved).
Skin and Body Protection
 Lab coat & natural rubber apron
 Full-length pants
 Closed-toe rubber or leather shoes
 Additional splash protection such as sleeves/ arm coverings
A fitted lab coat should be worn. Laboratory coat sleeves must be of a sufficient length to prevent
skin exposure while wearing gloves. As outlined in UCSF Personal Protective Equipment Policy,
personnel should also wear full length pants, or equivalent, and close-toed shoes. Full length pants
and close-toed shoes must be worn at all times by all individuals that are occupying the laboratory
area. The area of skin between the shoe and ankle should not be exposed.
Hygiene Measures
Avoid contact with skin, eyes and clothing. Wash thoroughly after handling. Wash hands before
eating. Remove contaminated clothing and wash before reuse.
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First Aid Procedures
General advice
ALL exposures should be evaluated immediately in an Emergency Department. Apply calcium gluconate
(see below) and call 9-911 from a campus phone or 415-476-1414 from a cell phone to get assistance
with transport to an Emergency Department.
If inhaled
Call 9-911 from a campus phone or 415-476-1414 from a cell phone to get assistance with transport to
an Emergency Department.
In case of skin contact
Immediately irrigate skin with plenty of water while removing contaminated clothing and shoes. As soon
as possible, apply calcium gluconate. Wearing compatible gloves, massage calcium gluconate gel into
the affected area. Re-apply every 15 minutes until medical help arrives. Call 9-911 from a campus
phone or 415-476-1414 from a cell phone.
In case of eye contact
Use the emergency Eyewash immediately, then apply 1% sterile calcium calgonate solution if
available.
Call 9-911 from a campus phone or 415-476-1414 from a cell phone.
NOTE: Use the entire 120 ml content during an emergency (eye exposure).
If swallowed
DO NOT force someone to drink anything if they are having nausea or pain. Call 9-911 from a campus
phone or 415-476-1414 from a cell phone.
Special Handling and Storage Requirements
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All users must be personally trained prior to working with HF
Ensure that you have all the PPE required for handling HF.
HF must always be stored in plastic (nalgene / polypropylene) containers. DO NOT store
HF in glass bottles/containers.
Store in corrosive/acid storage cabinet within a secondary containment (nalgene/
polypropylene tray or tub).
Do not store in the top most shelf of the storage cabinet. Note: In general, do not store
chemicals at or above eye level.
Ensure the container is tightly closed at all times.
Do not store with oxides, organic chemicals, bases or metals.
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Carefully carry the stock bottle in a rubber maid bottle carrier/nalgene secondary
container to the wet bench/chemical fume hood and pour out desired amount into a
smaller container.
Place stock bottle back in corrosive chemical storage cabinet with cap tightly closed.
Lab buddy system is highly recommended when handling HF (i.e. someone who knows
HF handling and emergency procedures should be nearby in the lab in case of
emergency). Lab emergency contact information must be readily available. The lab
personnel must have easy access to a telephone (landline or cell phone).
Spill and Accident Procedure
Chemical Spill Dial 9-911 from campus phone or 415-476-1414 from cell phone or 415-206-8522 (SFGH
only)
Spill – Assess the extent of danger. Assist contaminated or injured persons. Evacuate the spill area. Avoid
breathing vapors. If possible, confine the spill to a small area using a spill kit or absorbent material. Keep others
from entering contaminated area (e.g., use caution tape, barriers, etc.).
Small (<1 L) – If you have training, you may assist in the clean-up effort. Use appropriate personal protective
equipment and clean-up material for chemical spilled. Double bag spill waste in clear plastic bags, label and take to
the next chemical waste pick-up.
Large (>1 L) – Dial 9-911 from campus phone or 415-476-1414 from cell phone or 415-206-8522 (SFGH
only) for assistance.
Chemical Spill on Body or Clothes – Remove clothing and rinse body thoroughly in emergency shower for at least
15 minutes. See First Aid Procedures instructions above. Notify supervisor and EH&S at 415-476-1300.
Chemical Splash Into Eyes –Use Calgonate Emergency Eyewash immediately. See First Aid Procedures
instructions above. Notify supervisor and EH&S at 415-476-1300.
Medical Emergency
Dial 9-911 or 415-476-1414
Note: All serious injuries must be reported to EH&S at 415-476-1300 within 8 hours.
Minor Injuries– Go to Occupational Health Programs (OHP) Clinic, 415-885-7580, 2330 Post Street, Suite
460 Hours of Operation for Appointments: Monday - Friday 7:30 a.m. - 4:00 p.m. (except Holidays).
Note: All serious injuries must be reported to EH&S at 415-476-1300 within 8 hours.
Needle stick/puncture exposure (as applicable to chemical handling procedure) – Wash the affected area
with soap and water for 15 minutes. For mucous membrane exposure, flush the affected area for 15
minutes using an eyewash station. If experiencing pain or vomiting, call 9-911 for immediate transport to the
nearest emergency department. If you have NO symptoms, have the SDS ready and contact the Poison
Control Hotline at 1-800-222-1222 to determine if and what further care you may need.
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Decontamination/Waste Disposal Procedure
HF is listed as Extremely Hazardous (EH) Substance by the State. Even the containers
(irrespective of the size) which once held HF must be disposed of as hazardous waste with
an on-line hazardous waste tag affixed on the container.
Even the safety gloves that come in contact with HF (i.e., HF contaminated gloves) must be
disposed of as dry hazardous waste. All dry hazardous waste must be double bagged (use only
transparent bags) and affixed with an on-line waste tag.
General hazardous waste disposal guidelines:
Label Waste
 Affix an on-line hazardous waste tag on all waste containers using the Online WASTe
Program https://ehs.ucop.edu/waste/ as soon as the first drop of waste is added to the
container
Store Waste
 Store hazardous waste in closed containers, in secondary containment and in a designated
location
 Double-bag dry waste using transparent bags
 Waste must be under the control of the person generating & disposing of it
Dispose of Waste
 Dispose of regularly generated chemical waste within 180 days
 Empty Containers
o Dispose as hazardous waste irrespective of the container size
Use secondary containment
Safety Data Sheet (SDS) Location
Online SDS can be accessed at
http://www.fishersci.com/msdsproxy%3FproductName%3DA463500%26productDescription%3
DHYDROFLUORIC%2BACID%2BOPTIMA%2B500ML%26catNo%3DA463500%2B%26vendorId%3DVN00033897%26storeId%3D10652
Protocol/Procedure
Quantities covered by this SOP:
0-5 ml
Conditions covered by this SOP:
20oC – 40oC
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Purpose: 0.1-0.2% Hydrofluoric Acid solution in ddH2O is used to prepare pioloform film-coated
grid for electron microscopy
General experimental process covered by this SOP:
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All users must be trained prior to working with HF
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Lab coat, rubber aprons and double nitrile gloves are worn while handling HF solutions.
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All work must be done in a chemical fume hood.
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Never work alone when handling HF. Be sure that someone who knows HF handling and
emergency procedures is nearby in the lab in case of emergency. Lab emergency contact
information must be readily available. The lab personnel must have easy access to a
telephone (landline or cell phone).
Preparation of 0.1-0.2% HF working solution:
1) In a chemical fume hood, add 4-5 drops (about 100 µl) of 48-50% HF solution
to 30-40 ml ddH2O contained in a small Teflon Dispenser Bottle.
2) Mix the solution in the chemical fume hood.
Use HF working solution to prepare pioloform film:
1) Add a few drops of 0.1-0.2% HF working solution to one end of a glass slide
covered with pioloform film.
2) Slightly tilt the slide so that the HF solution travels underneath the film and
separate it from the slide.
3) Collect the HF waste solution in a plastic bottle.
Purpose: HF used to make metal-fluoride salt solutions for electrophysiology
NOTE: Whenever possible/practical, purchase the metal fluoride salt rather than making it
using HF described below:
1. Make working solution of HF:
a. In a chemical fume hood, HF is pipetted directly from the stock bottle to a premeasured volume of H20. For a 1 M solution, 1.81 ml of HF are added to 48.19 ml of
H20 in a polypropylene tube, using plastic pipette tips. Spent pipette tips are
discharged to a sealable plastic container. Stock solutions are labeled and kept in the
fume hood in sealed containers.
2. Make 0.5 M fluoride salt stock solutions
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a. In a chemical fume hood, titrate 10 ml of 1 M HF into 10 ml of 1M of metal
hydroxide solution or N-methyl-D-glucamine solution. (Note: because of their
physical properties, only NaF, CsF and NMDG-F are made in this fashion, by mixing
HF with solutions of NaOH, CsOH and NMDG respectively).
3. Make experimental metal fluoride solutions of up to 140 mM metal fluoride, 10 mM Hepes,
up to 5 mM EGTA and 2 mM MgCl2.
4. Metal fluoride solutions are buffered to a pH of 7.2 or above using HEPES and NMDG
solution and are not exposed to acidic solutions during experimentation.
5. Metal fluoride solutions are perfused to cultured cells during electrophysiological
recordings. Spent solutions are collected by vacuum suction into an enclosed container.
NOTE: Stock solutions are not stored beyond their day of usage, but are disposed of after
making experimental solutions. All solutions, waste products and HF contaminated plastic
(including pipette tips) are designated hazardous waste and disposed of as detailed in
"Decontamination/Waste Disposal Procedures"
Byproducts of HF neutralization reactions are similarly treated as hazardous waste and are
disposed of in the same fashion as HF as detailed in "Decontamination/Waste Disposal
Procedures". Na+, Cs+ and NMDG ions are not considered hazardous and do not require
additional disposal considerations different from those required for HF solutions.
NOTE
Any deviation from this SOP requires approval from the Principal Investigator.
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