This lesson covers the very common and well-known disinfectants chlorine and quaternary ammonium. We will talk about their advantages, disadvantages, and uses in addition to the types of microbes they can kill.
In other lessons, we described something known as a disinfectant. This is an agent that kills most, but not all, microbes on an inanimate object, such as a table’s surface. We also discussed some examples of chemical disinfectants, such as alcohols and phenols.
However, they aren’t the only types of disinfectants used. We’ll cover two more important ones in this lesson.
Disinfection with Chlorine
The first type of disinfectant we’re going to discuss is something I’m positive you have heard of, it’s called chlorine.
Chlorine is an element that has been used in everything from liquid disinfectants to poisonous gases. For our purposes, more technically, the specific kind of chlorine compound used in liquid disinfectants is known as sodium hypochlorite, which is found in household bleach. Chlorine is used at your local pool where you take a swim. That’s because water, especially warm stagnant water at your pool, is a great breeding ground for bacteria, viruses, fungi, and parasites. Chlorine is a great way to kill all of those if used in the proper concentration.
The great thing about chlorine, or bleach, is it’s readily available at your store and is relatively cheap. It’s also pretty darn easy to use and gets a lot of microbes in varying conditions, including different types of water hardness. However, if you’ve ever been around a serious concentration of bleach, I’m more than sure you know its disadvantages. It smells terrible, produces noxious gases, and can burn your eyes and nose. Also, it’s quite easily inactivated by organic matter.
I’ll explain what that means. Let’s say your backyard has a pool surrounded by trees. You have prepared a bucket full of water and bleach to clean the pool that has been dirtied with soil, leaves, and so on. There’s a little sponge floating on top of your bucket, you’ve got gloves on, a mask, and goggles to be safe from the bleach. You proceed to clean your empty pool.
However, after you test it for microbial levels, they are still sky high. You are positive you used the right concentration of bleach, so it should’ve gotten rid of a lot of microbes, but it didn’t.The mistake you made was that you didn’t pre-clean the pool. All of that dirt in the pool, considered to be organic matter and debris, stops the bleach from functioning properly. You must essentially pre-wash and pre-clean whatever it is you’re going to clean with bleach prior to actually cleaning it with your chlorine solution. That way, your chlorine compound can exert its maximal antimicrobial activity.The way by which chlorine kills microbes isn’t entirely understood yet.
We believe there’s a wide range of ways chlorine kills microorganisms, ranging from the inhibition of protein synthesis to breaking apart the nucleic acids, such as DNA or RNA, of the microorganism itself.
Quaternary Ammonium Compounds
Besides chlorine, another well-known category of disinfectants is known as quaternary ammonium compounds. These compounds are able to kill many fungi, bacteria, and viruses. However, they cannot kill off certain viruses and spores, the hardy forms some bacteria have. Namely, quaternary ammonium compounds can kill off enveloped viruses much better than non-enveloped viruses.You can liken a non-enveloped virus to one that has a hardy shell, like a nut, around its nucleic acid genome.
An enveloped virus is surrounded by a thin membrane, kind of like a thin balloon. Logically, it will be much easier to penetrate and pop a balloon-like exterior than the wood-like exterior of a nut. Likewise, it’s much easier to kill or disinfect a surface against a virus that is enveloped than non-enveloped.
The way by which quaternary ammonium compounds seem to kill some types of microbes is not only by destroying their cell membrane, such as the one I just mentioned, but also by destroying or inactivating important microbial proteins. The proteins these compounds destroys maybe involved in energy producing processes. You can liken these proteins to little pieces of coal being put into a coal plant in order to produce energy to power a city. If you destroy the coal, you’ll have nothing to put in the coal plant.
This means the city powered by the coal plant will shut down. Similarly, if a microorganism’s proteins are shut down, inactivated, or destroyed, they cannot be used to produce energy, which will cause the microbe to shut down, or die.The advantages of quaternary ammonium compounds include the fact that they can kill a wide variety of microbes and are easy to use.
The problem is that, in contrast to chlorine, high water hardness can affect their ability to combat microbes, and using material, such as a cotton cloth, along with these compounds to disinfect an area can also hinder their ability to kill off microorganisms. In any case, both chlorine and quaternary ammonium compounds are commonly used to clean areas, such as walls and floors, when their disinfection is necessary.
So, in summary, there are many types of disinfectants besides phenols and alcohols. One of those disinfectants is known as chlorine.
Chlorine is an element that has been used in everything from liquid disinfectants to poisonous gases. For our purposes, more technically, the specific kind of chlorine compound used in liquid disinfectants is known as sodium hypochlorite, which is found in household bleach. Besides chlorine, another well-known category of disinfectants is known as quaternary ammonium compounds.
Keep in mind that chlorine can work equally well in different types of water hardness. This is not the case for quaternary ammonium compounds whose capability to disinfect suffers with increasing water hardness.
Upon completing this lesson, you may be able to:
- Remember the technical term for chlorine
- State the advantages and disadvantages of chlorine as a disinfectant
- Mention the advantages and disadvantages of quaternary ammonium compounds as a disinfectant
- Know how water hardness and enveloped versus non-enveloped viruses affect quaternary ammonium compounds