Smartphone-integrated printed-paper sensor designed for on-site determination of dimethoate pesticide in food samples

• User-friendly and portable smartphone-integrated printed-paper sensor for on-site monitoring of dimethoate pesticide in foods. • Detection is based on the change of yellow color NPs to reddish-yellow when pesticide was introduced onto the fabricated paper. • A smartphone-color detector App and colorimetry were used for quantitative analysis of dimethoate in foods. • Advantages are rapid instrument-free detection and economic in terms of consumption of lower amounts of NPs solution. Herein, a user-friendly and portable smartphone-integrated printed-paper sensor was designed with Cu@Ag nanoparticles (NPs) for on-site monitoring of dimethoate pesticide in food samples, and the results obtained are compared with those obtained by UV-vis spectrophotometry. The working principle for identification of dimethoate pesticide is the change of yellow color NPs to reddish-yellow with associated bathochromic shift of absorption peak when pesticide introduced onto the fabricated paper or glass vial containing the NPs. A smartphone-color detector App and colorimetry were used for quantitative analysis of dimethoate in food samples. Linearity range for analysis of dimethoate using paper sensor and colorimetry were 100-2000 µgL -1 and 50-2500 µgL -1 with detection limit of 30 and 16 µgL -1 , respectively. The advantages of using smartphone-integrated paper devices are rapid, instrument-free detection and economic in terms of consumption of lower amounts of NPs solution compared to other NPs-based colorimetric methods.