Analysis of Consumer Products: Demonstrating the Power of LC-MS/MS for the Simultaneous Analysis of Caffeine and Other Methylxanthines in Guarana Fruit Powder Extract

Author(s)

Novaki, Luzia P. ^[1] ; Chinelatto, Ana M. ^[2] ; Silva, Vania A. B. B. ^[2] ; El Seoud, Omar A. ^[2]

Affiliation

^[1] ABC Fed Univ, Human & Nat Sci Ctr, BR-09210580 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Chem, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Chemical Education; v. 98, n. 6, p. 2083-2089, JUN 8 2021.
• Web of Science Citations: 0

Abstract

Dilute guarana (Paullinia cupana) powder aqueous extract is a soft drink that contains three structurally related methylxanthines (MXs), caffeine (CF), theobromine (TB), and theophylline (TP); CF is present in a large excess. Literature data show that values of lambda(max) and epsilon(max) of these three MXs are very close. Consequently, quantitative analysis using a single technique (UV-vis) is difficult, at best. We asked our students how to determine the three MXs simultaneously. They suggested use of chromatographic separation followed by mass spectrometry (MS) detection. Use of electrospray ionization solved the MX structure identification problem only partially because TB and TP have the same molar mass. Using LC-MS/MS solved this problem, as TB and TP have distinct retention times and fragmentation patterns. This is an important everyday situation (analysis of foods and drinks) because of the popularity of CF-containing drinks (guarana, coffee, tea, cacao) and health concerns about abuse of CF consumption. (AU)

• FAPESP's process: 14/22136-4 - Use of green solvents and their mixtures for optimizing chemical processes
• Grantee: Omar Abou El Seoud
• Support Opportunities: Research Projects - Thematic Grants