Dual colorimetric/electrochemical sensor of carbaryl in fruits on microfluidic paper-based analytical device connected with smartphone readout.

A dual colorimetric/electrochemical sensor integrated with a microfluidic paper-based analytical device (μPAD) is created for rapid and sensitive detection of cabaryl in fruit. For colorimetric sensor, quercetin modified silver nanoparticle (QCT-AgNPs) is synthesized via self-reduction, resulting in the color change from green to dark green in the presence of cabaryl, which can be readily observed via naked eyes. This colorimetric sensor provides a linear response of 5 – 50 μM quantified by Image J software. For electrochemistry, AgNPs/MXene nanocomposite electrode offers high electrocatalytic activity towards the detection of carbarly with a linear range of 0 – 60 µM and a detection limit of 0.01 µM. The limit of detection values obtained from this dual sensor are lower than a cut-off of carbaryl residue in food, which is 7 mg.kg−1 (35 µM) verifying the desired sensitivity of this platform. Ultimately, this dual sensor is successfully applied for on-site detection of carbaryl in the orange samples read out on the smartphone with satisfactory results. [Display omitted] • Dual colorimetric/electrochemicl sensor is developed on μPAD for cabaryl sensor • QCT-AgNPs is synthesized by self-reduction and applied for colorimetric detection. • AgNPs/MXene modified electrode provided high electrochemical sensitivity. • This platform is applied for on-site carbaryl detection in fruits on smartphone. [ABSTRACT FROM AUTHOR]