A novel microfluidic paper – based device with colorimetric assay for determination of catechol using poly(N-vinylpyrrolidone) -capped silver nanoparticles

Due to the harmfulness of catechol to the environment and human health, various analytical methods have been developed for its determination, including electrochemiluminescence, spectrophotometry, gas chromato-graphy, electrochemistry, capillary electrophoresis and high performance liquid chromatography(HPLC)[1]. However, these methods suffer from sophisticated operations and expensive instrumentations. In this work, a paper based device [2] was fabricated that can rapidly detect very low concentration of catechol using modified silver nanoparticles that were synthesized by facile PVP-stabilized method [3]. AgNPs paper-based sensor changed from light yellow to dark grey color after the addition of catechol due to nanoparticle growth and clusters formation. Two-dimensional optical scanners have been used as a low-cost detection system. Under optimized measurement conditions, the color intensities were altered as a function of catechol concentration. The color intensity change was linear with catechol concentration over the range of 50 μM–0.9 mM with a correlation coefficient of 0.993. This colorimetry method can detect as low as 5μM of analyte within <30 minutes on a white filter paper which was comparable to analytical laboratory-based methodologies. The proposed method was successfully applied for the determination of catechol in real samples, including tap water, perfume and cigarette smoke and satisfactory results was obtained.