3D printed portable instruments based on affordable electronics, smartphones and open-source microcontrollers suitable for monitoring food quality

This investigation was carried out with the aim of stressing that technologically-advanced systems can be prototyped and produced by using 3D printing and inexpensive electronic modules. In particular, open-source technologies are opening new exciting possibilities also in the area of chemical analysis, thus making possible the assembly of customized analytical devices by using widely available and low cost materials. Here, two different field-portable optical analytical instruments, one operating in the transmittance mode and the other in reflectance mode, were built up by combining 3D printed parts with common hardware components, such as Arduino boards, LEDs and photoresistors. They were employed to analyze the antioxidant capacity of several tea infusions by profiting from the Folin-Ciocalteu assay. A performance comparable with that displayed by research-grade spectrophotometers indicates that these easy-to-operate and low-cost devices can provide accurate and precise results, thus demonstrating that highly-sensitive optical instrumentations, useful not only in research and education environments but also in resource-limited settings, can be readily constructed by a DIY (Do-It-Yourself) approach.