What Is Isopropyl Alcohol and How Is It Used?
Why Is 70% the Most Effective Concentration of Isopropyl Alcohol for Disinfection?
Isopropyl alcohol, particularly in solutions between 60% and 90% alcohol with 10 – 40% purified water, is rapidly antimicrobial against bacteria, fungi, and viruses. Once alcohol concentrations drop below 50%, usefulness for disinfection drops sharply. Notably, higher concentrations of alcohol don’t generate more desirable bactericidal, virucidal, or fungicidal properties.
The presence of water is a crucial factor in destroying or inhibiting the growth of pathogenic microorganisms with isopropyl alcohol. Water acts as a catalyst and plays a key role in denaturing the proteins of vegetative cell membranes. 70% IPA solutions penetrate the cell wall more completely which permeates the entire cell, coagulates all proteins, and therefore the microorganism dies. Extra water content slows evaporation, therefore increasing surface contact time and enhancing effectiveness. Isopropyl alcohol concentrations over 91% coagulate proteins instantly. Consequently, a protective layer is created which protects other proteins from further coagulation.
Solutions > 91% IPA may kill some bacteria, but require longer contact times for disinfection, and enable spores to lie in a dormant state without being killed. A 50% isopropyl alcohol solution kills Staphylococcus Aureus in less than 10 seconds (pg. 238), yet a 90% solution with a contact time of over two hours is ineffective. Some disinfectants will kill spores with exposures times that exceed 3-12 hours, which are classified as chemical sterilants. So why do higher alcohol solutions yield fewer results for bactericidal and antimicrobial outcomes?
Why Doesn’t Isopropyl Alcohol Kill Bacteria and Fungal Spores?
Some bacteria transform into spore cells when external conditions are unfavorable; the result is reduced metabolic activity, higher ‘cidal’ resistance, and immunity from alcohol-based disinfectants. Spores lie dormant, and once conditions become favorable again, the microbe converts back to a vegetative state and grows actively. When examining the effectiveness of IPA, accurately translating its benefits and shortcomings require distinctions of identity, purity, sterility, and intended use. Disinfection, unlike sterilization, does not provide sporicidal attributes.
Is Sterilization with Isopropanol (AKA Isopropyl Alcohol or IPA) Possible?
Proper Uses of Isopropyl Alcohol Require Distinction Between Sterilization and Disinfection
Terms like disinfection and sterilization are often misunderstood and used interchangeably. The Center for Disease Control (CDC) defines terminology clearly:
Isopropyl alcohol is excluded from classification as a high-level disinfectant because of its inability to eradicate bacterial spores and hydrophilic viruses such as polio. Its low-level categorization outlines effectiveness for noncritical patient care devices such as blood pressure cuffs. IPA is also commonly applied during cleanroom wipedown for disinfecting tools and packaging that must pass into ultra-clean spaces.
Why Not Use Higher Isopropyl Alcohol (91%+) Concentrations?
When Is 99% Isopropyl Alcohol Used?
Is Isopropyl Alcohol Effective Against Fungus and Fungal Spores?
Isopropyl alcohol may be intermittently effective against fungus but it is not effective against fungal spores. Treatment of mold and fungus is generally considered a problem of moisture and humidity. Applying a surface level cleaner may have little or no effect on fungal removal. Bleach and hydrogen peroxide are more commonly associated with remedying mold and fungus outbreaks.
Officially, government organizations are somewhat conflicted on the use of bleach for mold.
What’s the Difference Between Types of Isopropyl Alcohol?
What Is USP-Grade Isopropyl and What Is It Used For?
The United States Pharmacopeial Convention (USP) is a nonprofit scientific organization that develops and disseminates public quality standards for medicines, food, and supplements. USP-grade certification ensures that both the isopropyl alcohol and any additives are of the highest purity, potency, and accurate concentration. Manufacturing, packaging, and storage must adhere to strict guidelines, and all production facilities must uphold FDA registration and inspection. These specifications improve consistency and safety for industrial, pharmaceutical, flavor & fragrance, or lab use.
What is NSF Grade Isopropyl Alcohol?
The National Sanitation Foundation (NSF) is a non-government, nonprofit organization that independently focuses on public health and safety of food industries, water supplies, consumer products, and human environments. Strict standards include product testing and material analyses in every aspect of a product’s development. NSF certification involves regular on-site inspections of manufacturing facilities and regular retesting of products. If a product fails to meet benchmarks, the NSF enforces actions including recall, public notification, or even de-certification.
What Is Pure Isopropyl Alcohol?
Pure isopropyl alcohol is manufactured and processed without common additives such as denaturants, which discourage human consumption. Pure isopropyl alcohol is not interchangeable with sterile or USP-grade isopropyl alcohol, but misnomers occur frequently because USP-grade alcohol is always in a pure state.
What Is Industrial Grade Alcohol?
Applications for industrial-grade isopropyl alcohol include:
- Remove ionic salts from PCBs, thermal paste from heatsinks and IC packages, and dissolve the organic acids in rosin-based soldering fluxes.
- Wipe down parts to mitigate general contaminants such as dust and debris present from other manufacturing processes.
- Strip surfaces of grime, grease, paint, & other coatings faster than low-concentration substitutes.
What is Food Grade Alcohol?
The use of isopropyl alcohol for products fit for human consumption is limited. Generally, ethyl alcohol is preferred for consumable products, as it is GRAS (generally regarded as safe). For food grade products, FCC (Food Chemicals Codex) accreditation establishes acceptable levels of purity and ingredient quality for products intended for human consumption. Isopropyl alcohol use is most commonly found during the preparation of food flavorings, fragrances, fats, oils, colorants, preservatives, sweetners, and probiotics.
What is Anhydrous Alcohol? Is Anhydrous Alcohol the Same as 99%?
Anhydrous simply means that a solution contains no water, and generally is of 99%+ concentration. Isopropyl alcohol that is 100% free of water is not feasible as it immediately absorbs water after exposure to humid air. High quality anhydrous alcohols produce a purity of +99.96%.
What is Denatured Alcohol?
Denatured alcohol contains an adulterant that renders the solution undrinkable. Sometimes the additive is scented which can reduce the nausea and odors associated with alcohol vapors. While some online stores may market their products as “100% pure denatured isopropyl alcohol”, this is a misnomer. Pure isopropyl alcohol does not contain any denaturants.
What Is Sterile Isopropyl Alcohol?
Sterile Isopropyl Alcohol meets the highest standards of purity in aseptic environments. Sterile certification ascertains 0.22-micron filtering, gamma irradiation between 25kGy – 50kGy and compliance of modified AAMI/ANSI/ISO 11137:2006 guidelines. Sterile IPA is packaged in a cleanroom and commonly used within the same environment for wipe down of pass-throughs, cleanroom furniture, laminar flow hoods, cleanroom furniture, and tables or work surfaces.
Is Isopropyl Alcohol the Same as Rubbing Alcohol?
Rubbing alcohol is an antiseptic, which U.S. Pharmacopeia standards defines as containing not less than 68% and not more than 72% of isopropyl alcohol. The remaining volume consists of water, with or without suitable stabilizers, perfume oils, and color additives certified by the FDA for use in drugs. The difference between rubbing alcohol and more pure forms of isopropyl alcohol is that rubbing alcohol contains denaturants which make the solution unpalatable for human consumption. Technically, all grades of rubbing alcohol containing 68% -72% isopropyl alcohol fall under the “rubbing alcohol” namesake for household use. Isopropyl alcohol concentrations >91% volume fail to provide bactericidal efficiency and are less effective for antiseptic use, thus its distinction as “rubbing alcohol” is not warranted and may cause confusion.
For more information, continue with the suggested reading below, or contact us about ordering in bulk, hazmat requirements, or for further questions on best usage and results.