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Carbon monoxide (CO) is a commonly poisonous gas. It is important to detect CO in daily life. Herein, a new and sensitive surface enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) coupled di-mode method was developed for CO, based on gold nano-enzyme catalysis and gold nanoprobes. CO can react with HAuCl4 to generate gold nanoparticles (AuNPs) in pH 5.2 HAc-NaAc buffer. The generated AuNPs exhibited SERS activity at 1620 cm−1 in the presence of Vitoria blue B (VBB) molecular probes, and an RRS peak at 290 nm. Based on the AuNP bifunctional probes, the increased SERS and RRS intensities respond linearly with the concentration of CO in the range of 100–1500 ng/mL and 30–5230 ng/mL, respectively. To improve the sensitivity, the produced AuNPs were used as nano-enzyme catalysts for the new indicator reaction of HAuCl4-ethanol (En) to amplify the signal. The sensitive SERS method was coupled with the accurate RRS method to develop a sensitive and accurate SERS/RRS di-mode method for determination of 3.0–413 ng/mL CO, based on the AuNP-HAuCl4-En nanocatalytic reaction and its product of AuNPs as SERS and RRS bifunctional probes. [ABSTRACT FROM AUTHOR]

• A COF of MaBd was prepared by melamine (Ma) and p -benzaldehyde (Bd). • MaBd can strongly catalyze the GC-HAuCl 4 nanoreaction. • A SERS quantitative method was constructed coupled aptamer with nanoreaction. • The method has high sensitivity and selectivity, and low blank. A highly catalytic and stable covalent organic frameworks (COFs) of MaBd were prepared by the polycondensation of melamine (Ma) and p -benzaldehyde (Bd), and characterized by molecular spectra and electron microscopy. MaBd strongly catalyze the new indicator reaction between glycol (GC) and chloroauric acid to generate gold nanoparticles (AuNP) with strong RRS effect at 370 nm and surface enhanced Raman scattering (SERS) effect at 1617 cm−1 using Vitoria blue B (VBB) as molecular probes. Combining the MaBd nanocatalytic amplification reaction with highly selective aptamer (Apt) of glyphosate (GLY), a new, simple and highly sensitive SERS method was developed with a linear range of 0.003−0.07 nmol/L, and the detection limit of 0.002 nmol/L GLY. GLY in soil samples were analyzed by this SERS method, with relative standard deviation of 4.78–5.71 % and recovery of 92.3–105.3 %. [ABSTRACT FROM AUTHOR]