A chemist’s guide to disinfectants – Chemical & Engineering News

“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.