Researchers from the American Chemical Society created a portable device that can detect how much capsaicin a pepper contains. Capsaicin gives peppers their spice. It also has a variety of health benefits including antioxidative, anticarcinogenic and anti-inflammatory properties.

Past methods to test for capsaicin levels have been to complicated, time-consuming or need expensive and bulk instrumentation. The researchers set out to overcome these issues.

A chili pepper-shaped device containing a paper-based electrochemical sensor can be connected to a smart phone to reveal how much capsaicin is in a hot pepper. Source: ACS Applied Nano Materials

The new device is shaped like a small chili pepper with a paper-based electrochemical sensor inside. It connects to a smartphone to display results. The sensor is made of graphene nanoplatelets that are doped with nitrogen atoms to improve electrical conductivity.

When a drop of diluted capsaicin was added to the sensor, the compound underwent oxidation and reduction reactions, which produced an electrical current that the device detects. After optimizing the sensor, the team used the device to determine the capsaicin concentration in six dried chili samples. They added chilis to an ethanol solution and shook it, then introduced a drop to the device as a sample. During testing, the device accurately measured capsaicin concentration from 7.5 to 90 UM in diluted samples.

A paper on this new device was published in Chemical and Engineering News.