2022-07-01 17:08


Conference: Bucharest University Faculty of Physics 2019 Meeting

Section: Optics, Spectroscopy, Plasma and Lasers

Spectroscopic detection and setting of azoic additives of interest in food reserach

Mihaela BOJAN, Cristian UDREA, Mihail Lucian PASCU

National Institute for Laser, Plasma and Radiation Physics


Terahertz – Time-Domain Spectroscopy, azo-food dyes, Fourier Transform Spectroscopy

Food dyes are currently used in common beverages and foods. They provide an attractive color to different drinks, desserts and even meat, but serve no nutritional purpose [1]. The spectrophotometric technique is able to determine peak absorbance of each separated dye, that is directly correlated with the color of the dye introduced in food. Two types of spectroscopic techniques have been used to analyze samples of different food dyes by following their maximum absorbancies, which allowed to identify them in a commercial drink; we present two non-invasive methods of detecting five out of commomnly utilized food dyes by adding them to a drink and comparing the transmision/absorbtion spectra of the uncolloured and colloured food. The food dyes that we have measured are: E 102-Tartrazine, E 110-Sunset Yellow, E 122-Azorubine, E 124-Red Ponceanu, E 155-Brun HT. Using a THz-TDS spectroscopic system, we have obtained the transmision spectra for dyes, absorbant paper and water, and we have determined the absorbance spectrum for each substance. Also, with this time domanin spectroscopy system, we have calculated the transmision spectrum for a comercial juice and the same juice in which we added the yellow dye (E 110) fro which we previously measured absorption signals. For the commercially available juice, E110 was not mentioned on the bottle. After comparing the two transmision spectra, we concluded that the transmision line for E 110 is visible in the transmision spectrum of the juice. i.e. it does contain the mentioned dye, though. Finally, we have measured the spectrum of all five food dyes, in the visible spectral range, with High Throughput Fourier Transform Spectrometer, obtaining the same kind of data. Having this kind of data base of transmision/absorbtion spectra for this set of food dyes, we can easily identify them in an alimentar product or drink, by spectroscopic methods.


1.COST Strategic Workshop – Food and Health: The Way Forward, Brussels, July 6, 2018

2. Sharma, V., McKone, H. T., & Markow, P. G. J. Chem. Ed. 2011, 88 (1), 24–28.

3. Hutt, P. B.; Hutt, P. B., II. Food, Drug, Cosmet, Law J. 1984, 39, 19.

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