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Consumer Safety

A chemist’s guide to disinfectants

Has your local store run out of sanitizing wipes? This cheat sheet can help you find and understand alternatives

by Craig A. Bettenhausen
May 1, 2020

 

20200501lnp2-shopping.jpg
Credit: Shutterstock
Retailers face rolling shortages of cleaners and disinfectants amid record demand from consumers.

“You’re a chemist, right? We’re almost out of wipes. Do you have any ideas on what else we could use to disinfect?” As supplies in grocery store cleaning aisles dwindle, chemists and other people with science backgrounds are fielding questions like these from friends and relatives about what they can use to kill the novel coronavirus, SARS-CoV-2.

Although manufacturers of disinfectants are doing all they can to keep up, demand is through the roof, and some raw material supply chains are strained. So how should you advise your friends and family on their available options?

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C&EN constructed this guide to explain the ingredients in disinfectants and help you give good advice. The most important thing is to read the labels. The US Environmental Protection Agency regulates disinfectants used on hard and soft surfaces under its authority to regulate pesticides. The agency vets and stands behind the efficacy promises on the labels, as long as you follow the instructions.

Labels offer guidance on how to use disinfectants safely—for instance, in a ventilated area—and they explain which cleaning products shouldn’t be mixed with other chemicals. Interactions you might not expect can create toxic gases or make the mixture stronger or weaker than anticipated.

Even the type of cloth you use when cleaning hard surfaces might alter how a disinfectant works. For instance, paper towels can decompose after long soaks in some disinfectants and deactivate others. The fabric in wipes is specially formulated to be unreactive, so experts advise that you don’t try to make your own premoistened wipes. Instead, you should spray a liquid disinfectant onto the target surface, let it sit for at least the “dwell” or “contact” time listed on the label, and then wipe dry or let the liquid evaporate. For soft surfaces like cloth or food, experts suggest different cleaning methods.

SARS-CoV-2 is an enveloped virus, which means it is surrounded by a lipid membrane. That’s good news, because a wide variety of disinfectants can disrupt lipid membranes, killing the virus they were protecting. Few disinfectants have been rigorously tested against SARS-CoV-2 in the lab, but the EPA maintains a public database of products it recommends for use against SARS-CoV-2 on the basis of their proven efficacy against similar viruses. Users can search this list by product name, active ingredient, type of product, and more. Users can search EPA's database, called List N, by product name, active ingredient, type of product, and more.

Disinfectant wipes and sprays used to clean hard surfaces are currently scarce, so we’ve curated the list below to describe the chemicals used in those products. You can use this information as a cheat sheet while you read the labels on the products you can find.


  • Alcohols

    How you’ll see them

    Ethanol
    (ethyl alcohol)
    Isopropanol
    (isopropyl alcohol or 2-propanol)

    How they work
    By disrupting a virus’s lipid envelope or by clumping or denaturing its proteins

    Wet contact time needed*
    1–5 minutes

    Use notes
    Ensure adequate ventilation and wear gloves

    Safety concerns
    Flammable, poison risk upon ingestion and can damage plastics and cause heady fumes

    Found in

    Hand
    sanitizers
    Wipes
  • Reducers

    How you’ll see them

    ʟ-lactic acid
    Citric acid

    How they work
    By denaturing a virus’s proteins, disrupting its lipid envelope, and reducing critical viral components

    Wet contact time needed*
    5 minutes

    Use notes
    Wear gloves

    Safety concerns
    Generally recognized as safe, though they can irritate skin

    Found in

    Sprays
  • Oxidizers

    How you’ll see them

    Peracetic
    acid
    Hydrogen
    peroxide
    NaClO
    Bleach
    (sodium hypochlorite)

    How they work
    By denaturing a virus’s proteins, disrupting its lipid envelope, and oxidizing sulfur bonds in proteins, enzymes, and other metabolites

    Wet contact time needed*
    Bleach, 1 minute; hydrogen peroxide, 5 minutes; peracetic acid, 2–5 minutes

    Use notes
    Ensure adequate ventilation and wear gloves

    Safety concerns
    Can irritate skin, mucus membranes, and airways and can damage clothing

    Found in

    Wipes
    Sprays
    Concentrates
  • Quaternary ammonium salts

    How you’ll see them

    Alkyldimethylbenzylammonium chloride
    (Benzalkonium chloride)
    Octyl decyl dimethylammonium chloride

    How they work
    By removing a virus’s lipid envelope, denaturing its proteins, and disrupting its enzymes

    Wet contact time needed*
    10 minutes

    Use notes
    Deactivated by hard water and fabric; wear gloves

    Safety concerns
    Can irritate the skin

    Found in

    Wipes
    Sprays
    Concentrates
    Antibacterial
    hand soap
  •  *The time the disinfectant should sit on a surface to ensure it works before being wiped away

Sources: US Environmental Protection Agency; Ryan Cotroneo/UNX Industries; Steven Bennett/Household and Commercial Products Association; Kevin Coyne/Wexford Labs; J. Vet. Med. Sci. 2000, DOI: 10.1292/jvms.62.85; Kirsten M. Thompson, “The Science of Disinfectants,” Cleaning and Maintenance Management, April 25, 2012; ScienceDirect.


Note: To sanitize soft surfaces such as clothes and food, use these tried-and-true methods. To disinfect textiles like your clothes, running them through the laundry with detergent is the best choice. For your hands, soap is the best tool, and hand sanitizer is a good on-the-go alternative if you’re not near a sink. For fruits and vegetables, the US Department of Health and Human Services says to cut away any damaged or bruised areas, then rinse under running water without soap, bleach, or commercial produce washes. The agency recommends you don’t wash bagged produce marked “prewashed” or meat, poultry, or eggs.

CORRECTION

This story was updated on May 2, 2020, because the labels for hydrogen peroxide, ʟ-lactic acid, and peracetic acid did not appear with the corresponding structures. The structures have been moved accordingly.

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Comments
Doug Beight (May 2, 2020 12:27 AM)
Several of the structures in the article are mislabelled. Namely, structures for L-lactic acid is peracetic acid, peracetic acid is hydrogen peroxide, and hydrogen peroxide is L-lactic acid.
Krishna (May 2, 2020 10:35 AM)
Doug is right! Labels are wrong!
Craig Bettenhausen (May 4, 2020 8:58 AM)
Thanks! We got a few wires crossed at first, but it should be fixed now.
Asmau Abubakar (May 3, 2020 2:40 PM)
An interesting piece of knowledge, one can try it in a school laboratory.
Marya Lieberman (May 6, 2020 10:41 AM)
These wet contact times must correspond to some concentration of the disinfectant materials--can you list the concentration for each substance? Also, note that some solutions (such as dilute bleach at levels recommended for sanitizing solutions) are stable for less than 24hr.
Philip Jewess (May 6, 2020 10:45 AM)
I have been using a Dettol black mildew remover (mostly hypochlorite) as I know that most viruses are quite sensitive to bleach. If you can put up with the choking fumes, bleached spots on clothes and removing ink from envelopes and documents it's probably one of the most effective.
Jim Smith (May 6, 2020 10:58 AM)
One other thing to remember when trying to sanitize or disinfect soft surfaces like clothing: ironing. Ironing, especially with a steam setting, will usually raise the temperature of articles well past what viral particles can tolerate.
Paul Glaser (May 6, 2020 12:18 PM)
What's the guidance on the use of Chlorhexidine in the US, Canada, & Mexico for hard-surface applications, especially re: COVID-19 ?
James Gaidis (May 6, 2020 12:46 PM)
Interesting article for junior chemists. Can you come up with a similar article that chemists would like to send to friends and relatives who are not even up to junior chemist standards? Something that sounds like expert advice without the pictures, which mean nothing - even less than nothing - to non-chemists. I don't mean it should be non-chemical, just that when I say I'm a chemist, the more common response is "Oh, I hated chemistry!" or "I almost flunked chemistry."
We have got to impress the non-chemists of the world that chemicals are good (if used properly) without overexplaining.
Joseph DiVerdi (May 6, 2020 1:05 PM)
What about representative concentrations? Inquiring chemists want to know - it's a chemistry thing.
Rider Barnum (May 7, 2020 8:14 AM)
I agree. Because the "Wet Contact Time Needed" is shown in the infographic, the concentration is VERY important. This could also lead the the common misconception that any concentration of alcohol is effective, rather than >60% required to be effective against COVID-19 virus. I understand that it's hard to state exact numbers in some cases, but at least minimum approximations. Like the quaternary ammonium compounds listed above require at least 650ppm to be effective at 10 min, or 5 min when 800-1000ppm.
Jim Smith (May 7, 2020 9:08 AM)
Actually, the contact times are even more particular than that. The contact times are based upon the product passing the AOAC Use-Dilution Test in the allotted time frame. So, if you think your disinfectant can pass the test in 5 minutes, it gets tested for 5 minutes. If it passes, it can make the claim that it will kill organism X in 5 minutes.

Each organism claimed on the label of an EPA registered disinfectant must have the disinfectant tested against it, and it must be shown to pass. So, there can be wildly different contact times between disinfectants of basically the same makeup -- it all depends on how the Primary Registrant (entity holding the formula and pursuing the claims) has it tested, and if it passes.
Tony Wood (May 6, 2020 1:31 PM)
Please send the graphic images from the disinfectant webpage for inclusion into instructional training materials. Do you have any specific recommendations for disinfection of full-face masks and SCBA respirators prior to sharing with other users?
Tony Wood
Director, National Spill Control School
Advisors to the National Response Team (OPA '90)
Jim Smith (May 7, 2020 9:20 AM)
Tony, there disinfectants with directions on how to decontaminate turn-out gear (which I think SCBA and full-face masks would be a part of). There is a guideline here (https://www.firehouse.com/safety-health/ppe/turnout-gear/document/21132531/sog-for-firefighter-turnout-gear-cleaning-during-covid19-pandemic), which I found by searching "disinfectants for turnout gear".

Full disclosure: my company produces a disinfectant under one of the registrations listed in the guide, but neither we nor our product are listed in the guide.
Edward Rau (May 6, 2020 8:44 PM)
Your listing of safety concerns associated with Quaternary Ammonium Salts minimizes the risks, particularly of chronic exposure. Risks posed by consumer products formulated with these compounds include eye injury, allergic rhinitis, asthma and contact dermatitis. They may also promote antibiotic resistance in bacteria, have toxicity to mammalian reproductive systems and some are persistent pollutants in the environment.
Kenneth Kustin (May 7, 2020 9:24 AM)
While making a chemist's guide to disinfectants is useful and helpful, a number of important chemical disinfectants was overlooked in the oxidizer category. In particular, chlorine dioxide (ClO2) and ozone (O3) should have been included. Chlorine dioxide is often confused with chlorine bleach, probably because of the reference to the presence of a chlorine atom in each molecule. However, ACS Chemists would surely appreciate that ClO2 has the oxidation state Cl(IV), in contradistinction to the Cl(I) oxidation state in hypochlorite (bleach). ClO2 is effective at low concentrations against a broad spectrum of microorganisms, while also being less corrosive to materials than bleach. As a result, ClO2 products were used in the recent past against the Ebola virus, and ClO2 products are currently on the EPA's List N: Products with Emerging Viral Pathogens AND Human Coronavirus claims for use against SARS-CoV-2 and the CDC list for decontaminating N95 masks (https://www.cdc.gov/niosh/npptl/respirators/testing/DeconResults.html) that bleach degrades. The ACS readership would appreciate including descriptions of ClO2 and O3 in the guide, to help direct readers to these disinfectants for use in this critical time.
Gary Bangs, CIH (May 13, 2020 11:25 AM)
Thanks for the information. I wasn't familiar with the citric acid and L-lactic acid being used to disinfect coronavirus.

I did note, however that you mention bleach but not the recommended concentration, or even that it should be diluted. That information is of course on the label, but since you show ready-to-use products as well, it might be safer to clarify that.
Be well.
Christian Nunez (May 16, 2020 9:35 PM)
Along with congratulating the magazine, I want to request if possible? Use this information for my organic chemistry classes at my university? Of course with his citation from the magazine. What I want to do is translate the article, draw the molecules and create a infographic in spanish. For my course and my community, will that be possible? I am looking forward to your response.
Greetings
Christian
Catalin (May 17, 2020 6:19 AM)
Hello. Lacking easy access to more chemically strong disinfectants, I am wondering if washing the packages of the goods one buys from the supermarkets with soap and water can be of help or does not have any effect at all. Can you please advise? Many thanks
Kesav (May 22, 2020 7:43 AM)
Good to educate ourselves on disinfectants and cleaners.Hats off to the detailing. You can buy disinfectant spray online in India at ibuychemicals.com and many other cleaning products that are earth friendly.
Dr. S. Divakaran (May 28, 2020 8:17 PM)
Often the term killing the virus is used to mean disrupt or damage the integrity of the virus. It is better to say "inactivate the virus". I recall a friend asked me if you say a virus is not a living thing how can you kill it.
Kerry Phillips (July 8, 2020 11:35 AM)
I'm very curious about the usage of Triethyleneglycol as a virus inactivator because it is a dessicant that was used in the fifties for There are a few companies out there promoting Hypochlorus Acid with a specific PH balance that they claim to be benign to humans and safe for consumption and clothing etc as they are using it in fogging devices to dry saturate surfaces to inactivate. Specifically walk in fog booths destined for airports etc. Any thoughts on that?
Greenwich cleaners (September 20, 2020 6:48 PM)
Dude this is mind blowing information to me! "Even the type of cloth you use when cleaning hard surfaces might alter how a disinfectant works. For instance, paper towels can decompose after long soaks in some disinfectants and deactivate others" are you kidding?! im going to have to figure out if im using the right products. im sure most cleaning services dont think this deeply about it so thanks a ton for sharing. just gave us our edge :)

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