Semi-sacrificial template growth-assisted self-supporting MOF chip: A versatile and high-performance SERS sensor for food contaminants monitoring

Abstract

Surface-enhanced Raman scattering (SERS) with its outstanding performance in ultra-sensitivity has been applied in contaminants monitoring. Herein, a facile strategy of integrating oriented layered MOF nanoarray with controlled electrodeposition of gold nanoparticles via semi-sacrificial template method was proposed to fabricate a versatile self-supporting MOF chip (S-MOF@Au) for efficient SERS detection of food contaminants. The S-MOF was ingeniously formed by directly using flexible Ni sheet as both metal source and scaffold, which in favour of greatly improving intrinsic electrical conductivity during electrodeposition process as well as endowing prepared chip with uniform distribution of gold nanoparticles and high stability. Furthermore, amounts of SERS “hot spots” in the oriented layered S-MOF@Au can yield strong electromagnetic field for Raman amplification with superior reproducibility. By virtue of good flexibility and pre-concentration effect of S-MOF@Au, tartrazine (TA), chloramphenicol (CP), imidacloprid (IDP) and crystal violet (CV) in food samples were sensitively detected using three collected approaches (drip coating, soaking and wiping) with low limits of detection (1.0 × 10−9 M for TA, 8.0 × 10−11 M for CP, 6.4 × 10−11 M for IDP and 5.0 × 10−12 M for CV), wide linear detection ranges (1.0 × 10−8 – 1.0 × 10−3 M for TA, 1.0 × 10−10 – 1.0 × 10−6 M for CP, 1.0 × 10−10 – 1.0 × 10−7 M for IDP and 1.0 × 10−11 – 1.0 × 10−7 M for CV) and satisfactory recoveries (96.2 – 125.1%). This method provides a novel strategy to develop an advanced SERS platform for efficient food contaminants monitoring.