Drop, drop, drop. It takes me back to high school chemistry—slowly adding a titrant to a solution, looking for a change in the color. Titration can be used to analyze the concentration of something in many solutions and applied to a variety of experimental situations, from biomedical and food science to environmental and pharmaceutical fields. When a lot of titration needs to be done or performed more accurately, going drop by drop, all by hand, might not do the job. In such cases, it’s time to use a titrator.
As explained by Jiefu Yin, laboratory manager at the Cornell Energy Systems Institute (Ithaca, NY), “Titrator or titration is a broad definition that covers different types of techniques in different applications.” He adds, “Titration is one of the traditional chemical quantitative methods that still shows its magic in our current digital world.”
Titration is versatile. It is “a quantitative analytical method that uses chemical reactions to determine the amount of one or several compounds in a mixture,” Yin says. “Titration has been utilized to determine different types of compounds: acid-base, water, organic molecules, etc.”
Types of titrators
Titrators come in various versions, such as Karl Fisher and potentiometric platforms. Really, many setups could be called a titrator. As Yin explains, “A titrator can be as simple as a combination of a flask and burette or as complicated as a digital device.”
A potentiometric titrator for example, automatically runs a titration of a reduction-oxidation reaction. Instead of using a color indicator, however, the potential is measured between two electrodes.
At the Cornell Energy Systems Institute, Yin uses a Karl Fischer titrator, which depends on an electrochemical reaction in the solution. This device “can be used to determine the water amount in a liquid/solid, and the detection limit is in parts per million level,” he explains. “It can be used in a wide range of applications, such as quality control, food industry, battery industry, etc.” In fact, researchers at the Cornell Energy Systems Institute use the titrator “to determine the water amount in the electrolyte that fills lithium-ion batteries,” Yin says. “It is critical to know the moisture level in lithium-ion batteries, as lithium is highly reactive with water and can cause severe safety problems.”
Picking a platform
To select the right platform, consider the application and important features. For example, a Karl Fischer titrator can be a portable device, which would be very useful in environmental applications. Given the variety of options, though, researchers often need help in making the best choice.
Lab Manager offers a couple of useful tools that serve as a starting point, including the “Titrator Types and Tips” infographic.
Once you have decided on a type that will meet your needs, visit manufacturer sites to find specifications such as accuracy, software, different burettes and sensors, etc. For example, METTLER TOLEDO (Columbus, OH), hosts a page on titrators, and Thermo Fisher Scientific (Waltham, MA) maintains a page on potentiometric titrators.
From the grueling manual method to automatic platforms, titration can be used in the lab and beyond. I never knew how far this method could be applied as I plodded through titrations by hand decades ago. It’s far more than drop, drop, drop.