Difference Between Detergent and Chaotropic Agent

The key difference between detergent and chaotropic agent is that detergents can denature proteins by solubilizing hydrophobic groups, whereas chaotropic agents can denature proteins by weakening hydrophobic effect.

Detergents are surfactants. These compounds have cleansing properties. The main action of these compounds is to denature protein compounds. However, there are non-detergent compounds that can denature proteins. Chaotropic agents are such non-detergent compounds.

CONTENTS

1. Overview and Key Difference
2. What is a Detergent
3. What is a Chaotropic Agent
4. Side by Side Comparison – Detergent vs Chaotropic Agent in Tabular Form
5. Summary

What is a Detergent?

Detergents are surfactant compounds that have cleansing properties. And, these compounds can be single surfactants or mixtures of surfactants. They are used as dilute solutions. Usually, detergents fall under the category of alylbenzenesulfonates. They are similar to soap but are different from soap since they are more soluble in hard water due to the presence of polar sulfonate groups.

Moreover, there are three major types of detergents as cationic, anionic and non-ionic detergents. Cationic detergents are a type of surface-active agents that contain positively charged functional groups in the head of the molecule. Most of these surfactants are useful as antimicrobials, antifungal agents, etc. It is because they can disrupt the cell membranes of bacteria and viruses. The most common functional group we can find in these molecules is ammonium ion.

Anionic detergents are a type of surface-active agents that contain negatively charged functional groups in the head of the molecule. Such functional groups include sulfonate, phosphate, sulfate and carboxylates. These are the most common surfactants we use. For example, soap contains alkyl carboxylates.

Non-ionic detergents are a type of surface-active agents that have no net electrical charge in their formulations. That means the molecule does not undergo any ionization when we dissolve it in water. Furthermore, they have covalently bonded oxygen-containing hydrophilic groups. These hydrophilic groups bind with hydrophobic parent structures when the surfactant is added to a sample. The oxygen atoms in these compounds can cause the hydrogen bonding of the surfactant molecules.

What is a Chaotropic Agent?

Chaotropic agents are chemical substances in an aqueous solution that can destroy the hydrogen bond network between water molecules. This is known as chaotropic activity. This destruction can affect the stability of the native state of macromolecules, such as proteins and nucleic acids. Chaotropic agents can denature proteins by weakening the hydrophobic effect of proteins. For example, chaotropic agents can increase the randomness of protein molecules, which cause the denaturation of the protein.

Some examples of chaotropic agents include ethanol, n-butanol, guanidinium chloride, lithium perchlorate, lithium acetate, magnesium chloride, phenol, 2-propanol, thiourea, and urea. The action of denaturation in these chemical species can be different from each other depending on their chemical structures; e.g. ethanol can interfere with the non-covalent bonds of proteins and nucleic acids.

What is the Difference Between Detergent and Chaotropic Agent?

Detergents are surfactant compounds that have cleansing properties. Chaotropic agents are chemical substances in an aqueous solution that can destroy the hydrogen bond network between water molecules. The key difference between detergent and chaotropic agent is that detergents can denature proteins by solubilizing hydrophobic groups, whereas chaotropic agents can denature proteins by weakening hydrophobic effect.

The below infographic summarizes the difference between detergent and chaotropic agent.

Summary – Detergent vs Chaotropic Agent

Detergent compounds and non-detergent, chaotropic substances are important as cleansers. The key difference between detergent and chaotropic agent is that detergents can denature proteins by solubilizing hydrophobic groups, whereas chaotropic agents can denature proteins by weakening hydrophobic effect.

Reference:

1.“Chaotropic Agent.” Wikipedia, Wikimedia Foundation, 26 Nov. 2019, Available here.
2.“Detergent.” Wikipedia, Wikimedia Foundation, 27 Mar. 2020, Available here.

Image Courtesy:

1. “Diskflaskor” By Nordelch – Own work (CC BY 3.0) via Commons Wikimedia
2. “Sample of Absolute Ethanol” By LHcheM – Own work (CC BY-SA 3.0) via Commons Wikimedia