Self-calibrated paper-based nanoarrays for background-free quantitative detection of pesticides using self-assembly and mask-assisted techniques.

Flexible surface-enhanced Raman scattering (SERS) has received considerable attention in the field of rapid analysis. However, obtaining accurate quantitative SERS results remains challenging. Here, we develop a SERS sensor based on self-assembly and mask-assisted techniques for the precise transfer of Au@PB@Ag nanoarrays onto filter paper. Prussian blue (PB) as an internal standard (IS) is used to calibrate the fluctuations in the SERS signal induced by the microstructure of the filter paper, and can generate a local plasmon resonance under a Raman laser at a wavelength of 633 nm, which enables a dual electromagnetic enhancement of the internal self-calibration and external target molecule signals. The SERS substrate has a low limit of detection of 3.96 × 10−9, a uniformity relative standard deviation (RSD) of 9.94 % (16.85 % uncalibrated), a repeatability RSD of 9.43 % (31.2 % for Au@Ag NPs), and remains stable for more than 45 days. Thiram and thiabendazole in fruit juices can be quantitatively detected using patterned transfer monolayer arrays with a common dropper. The R2 coefficients of the pesticide concentration and Raman intensity fitting curves improved from 0.9659 and 0.9499 to 0.9976 and 0.9928, respectively. Thus, paper-based Au@PB@Ag nanoarrays have facilitated the development of SERS technology for practical applications. [Display omitted] • A new approach combining mask-assisted and self-assembly techniques. • Surface-enhanced resonant Raman scattering (SERS) effects with dual electromagnetic enhancement. • IS calibration of inhomogeneities due to microstructure of filter paper. • RSD of 9.43 % for paper-based SERS sensor (compare to 31.2 % for Au@Ag NPs). • Application of the SERS method to TBZ and TRM determination in fruit juices. [ABSTRACT FROM AUTHOR]