Researchers have developed a fluorescent caffeine detector and detection kit that lights up like a traffic light when caffeine is present in various drinks and solutions so consumers can keep track of their intake.

The novel caffeine sensor, named Caffeine Orange, was developed by a team of researchers led by Professor Young-Tae Chang from the National University of Singapore and Professor Yoon-Kyoung Cho from Ulsan National Institute of Science and Techonolgy (UNIST) in Korea. Their research work was published in Scientific Reports (Nature Publishing Group) on 23 July 2013.

Researchers said “naked-eye sensing” for various caffeine concentrations is possible with the “non-toxic” caffeine detection kit, based on colour changes upon irradiation with the detection kit, which emits a green laser pointer light into drinks. Solutions with high caffeine concentrations turn red, while solutions with moderate and low caffeine concentrations turn yellow and green respectively.

Development process

To make the sensor fully functional, researchers needed to extract caffeine from solutions and measure its levels. An automated system that incorporated a ‘microfluidics’ technique developed by the UNIST research team, called ‘lab-on-a-disc’, was applied to extract and measure the caffeine.

“Applying lab-on-a-disc technology to real life application with the novel caffeine sensor is very meaningful,” said Professor Cho. “We will continue to develop new sensors applicable to various materials utilising lab-on-a-chip technology,” he said.

Caffeine safety a global concern

The consumption of caffeine has come under the spotlight again globally in the last year. Australian Food News reported in May 2013 that the US Food and Drug Administration (FDA) had announced it would investigate the safety of caffeine in food products, particularly its effects on children and adolescents. In February 2013, Australian Food News reported that the European Commission (EC) had decided to ask the European Food Safety Authority (EFSA) to investigate the safety of caffeine.

“You can use this caffeine detection kit as a ‘traffic-light caffeine amount designator’,” said Professor Chang. “The reddish orange colour indicates a stop sign for people who cannot uptake caffeine, while yellow and green indicate a warning signal and a safe zone respectively,” he said.

The research was supported by the Singapore-Peking-Oxford Research Enterprise and Word Class University program, and Basic Science Research Program through the National Research Foundation (NRF) by the Ministry of Education, Science and Technology in Korea.