Writing in the American Chemical Society (ACS) journal Analytical Chemistry, Maik Jochmann and his team from the University of Duisburg-Essen said:
“Caffeine-containing drinks are the most popular type of beverage in the world… however, people prefer food products made from natural sources to those made of artificial chemicals.”
For instance, the US Food and Drug Administration (FDA) demands that caffeine be listed of labels when it is added during production, but not for drinks made from tea or coffee.
“In consideration of the growing demand for natural drinks on the one hand, and the significant price differences between naturally occurring caffeine source and synthetic caffeine sources and synthetic caffeine chemicals on the other on the other, there is a high risk of fraud by false declaration of caffeine origins,” Jochmann et al. wrote.
Faster, simpler method…
Given that food regulatory agencies require that caffeine be listed on package labels, but did not require information as to whether it originated from synthetic or natural sources, the scientists aimed to develop a faster, simpler method for categorising its origins in products.
Using a technique coupling high temperature reversed-phase liquid chromatography with isotope ratio mass spectrometry (HT-RPLC/IRMS), they examined the differences in carbon isotopes found in caffeine produced by plants and caffeine produced in laboratories with petroleum-derived molecular building blocks.
Jochmann et al. said that the analysis took as little as 15 minutes, and they disconvered in tests that four out of 38 drinks (not named in the study) supposed to contain natural caffeine sources actually contained synthetic caffeine, despite ‘natural’ labeling professions to the contrary.
Drinks 'probably' mislabeled
They wrote: “Four out of the 38 tested drinks contain caffeine with [isotopic signature] δ13C values more negative than −33‰ [parts per thousand] falling into the group for synthetic caffeine. These four probably mislabeled drinks are one instant drink mix, two bottled iced tea drinks, and one maté drink.”
According to Jochmann et al., advantages of their new method included simple sample preparation time, short analysis time, long-term column stability and high precision of δ13C values.
“It has the potential to become a routine method for authenticity control of caffeine-containing drinks,” the scientists added.
Title: ‘Caffeine in Your Drink: Natural or Synthetic?’
Authors: L.Zhang, D.M Kujawinski, E.Federherr, T.C Schmidt, M.A Johnmann
Source: Analytical Chemistry, February 17 2012, doi: 10.1021/ac203197d