Construction of Jaffe reaction-based SERS chip for determination of trace picric acid

Abstract

Picric acid (PA) has a severe environmental risk and security problem owing to its unstable property and high toxic. On-field selective and sensitive detection of trace PA is also a challenging task. PA molecules due to poor affinity to surface of noble metal nanoparticles are hardly detectable by surface-enhanced Raman scattering (SERS) method. In this work, silver shell and gold core nanoparticles with inositol hexaphosphate inner gap (Au@IP6@AgNPs) is prepared and then two-dimension (2D) substrate at the ITO surface (designated as ITO-Au@IP6@Ag) is formed via self-assembly. For capturing PA, we firstly modify creatinine (CRN) molecules onto the ITO-Au@IP6@Ag designated as ITO-Au@IP6@Ag@CRN to construct a specific SERS chip for PA, taking advantage of Jaffe reaction between PA and CRN. The generated Jaffe Complex has the greater Raman scattering section with respect to PA. Therefore, such chip-based SERS array for PA shows a good sensitivity and selectivity and the limit of detection at 3.9 × 10−11 mol/L could be reached. As real applications, the ITO-Au@IP6@Ag@CRN chips have been used for identification of PA in environmental samples such as clothing, envelope, and luggage, and determination of trace PA (~10−7 mol/L) in lake water. It demonstrates a promising perspective for on-site detection of the explosive for public security.