“…Absorption spectroscopy is well-established for quantitative colorimetric analysis, 36 but requires a light source, grating, and a detector, limiting its field use and accessibility. Recently, machine learning (ML) has emerged as a tool in various scientific fields, 37–41 offering an alternative route to quantitative colorimetric analysis that could be incorporated into mobile phones for field applications. Machine learning has been shown to improve efficiency, reduce costs and simplify tasks that would otherwise be complicated or were previously not possible.…”