Synthesis of flexible and stable SERS substrate based on Au nanofilms/cicada wing array for rapid detection of pesticide residues

A kind of flexible and stable Au nanofilms/cicada wing (Au NF/CW) nanocomposite with high surface-enhanced Raman scattering (SERS) performance was synthesized via a facile magnetron sputtering technique. By varying the sputtering time, optimal SERS substrate with sputtering time of 35 min (Au NF/CW-35) was obtained. The limit of detection (LOD) for Rhodamine 6G (R6G) was evaluated at 10(-8)M and the maximum value of enhancement factor (EF) was 2.20 x 10(6). Moreover, Raman intensity of R6G reduced only by 10.94% after aging for 60 days and the relative standard deviation (RSD) values were lower than 13%. The Au NF wrapped SERS substrates exhibited a high sensitivity, stability and reproducibility for analyte, which demonstrating an application potential in trace detection. Therefore, the SERS technique based on Au NF/CW-35 substrate was applied to solve the urgent problems of pesticide residues on fruit peels and the LOD for acephate was 10(-9) mg/ml on pear peels via a simple "pasted and peeled off' approach. The high linear dependence indicated that Au NF/CW-35 substrate not only offered a wide potential application for rapid and quantitative detection of trace pesticide residues on real samples but also provided new ideas for bionics.