DiColorimetry: A smartphone application for colorimetric analysis of phenolics and antioxidant activity in vegetable oils.

This method presents DiColorimetry, an author-developed Android application for smartphone-assisted colorimetric assessment of total phenolic content (TPC), radical scavenging activity (RSA) and general colour characteristics in vegetable oils. Smartphone-based imaging itself is not presented as a new analytical principle; the methodological contribution is the integration of previously separate image acquisition, ROI-based colour extraction, assay-specific signal processing, calibration or reference handling, calculation and data export within a single mobile workflow.•The application integrates assay-specific TPC and RSA analysis with a standalone colour-data extraction module, including region-of-interest selection and CSV export.•Analytical performance was evaluated using 40 commercial vegetable oil samples from ten botanical categories and compared with UV/VIS spectrophotometry under controlled imaging conditions using a Samsung Galaxy A33 5 G smartphone.•DiColorimetry showed close agreement with the reference method: mean signal-acquisition relative standard deviations were below 1%, and all paired TPC and RSA results showed absolute relative deviations below 5%.•The standalone module provides RGB, HSV, CIELAB, and CIELCh values but requires a user-established calibration model for quantitative application. DiColorimetry is intended as an integrated assay-specific smartphone readout and screening tool rather than as a new smartphone-imaging principle or a universal replacement for calibrated analytical instrumentation.