The geek and the chemist: Antioxidant capacity measurements by DPPH assay in beverages using open source tools, consumer electronics and 3D printing

Microcontrollers and single-board computers are widespread tools for innovative educational labs, for prototyping and for accomplish everyday tasks by expert users. Moreover, these modules are opening new exciting possibilities in the area of biological and chemical assays. In this study a Raspberry Pi computer assembled with 3D printed parts and inexpensive opto-electronic components were employed to analyse the antioxidant capacity of several bottled tea performing diphenylpicryl-hydrazyl (DPPH) tests. A dedicated python software allowed the execution of the analysis controlling the device through a small LCD touch screen or remotely through secure connections with other devices. The rRaspberry Pi-based measurements were compared with a research-grade spectrophotometer showing excellent correlation (R2 = 0.9996) and no significant differences (p < 0.05) in the range of measured values. We strongly believe that this approach could support diagnostics progress in resource-poor countries and open new opportunities in research and education.