Smartphone-based digital images in analytical chemistry: Why, when, and how to use

Smartphone-based digital image photometry (SDI) has been widely exploited for a variety of analytical applications owing to its advantages, such as portability, low energy demand, cost-effectiveness, user-friendliness, and the wide availability of instrumentation. This approach has often been combined with microanalysis (e.g., spot tests and microfluidics), microextraction, and environmentally friendly strategies. This article presents a critical overview of SDI, highlighting its advantages and challenges, as well as strategies to achieve reliable results, including image acquisition and data processing. Recent innovative approaches as well as applications in environmental, food, fuel, pharmaceutical, clinical analysis and bioanalysis are highlighted.