Recognition and quantitative analysis for six phthalate esters (PAEs) through functionalized ZIF-67@Ag nanowires as surface-enhanced Raman scattering substrate

A novel surface enhanced Raman scattering (SERS) method was developed based on Ag nanowires embedded into functionalized metal-organic framework ZIF-67 (ZIF-67@Ag NWs) composite as substrate, which was applied for rapid recognition and sensitive detection of six PAEs. The Raman signals for PAEs detection were gained at ZIF-67@Ag NWs substrate mainly due to the "sharp tip effect" of rough Ag nanowires and excellent absorptive capacity of ZIF-67 to capture targeted molecules into the electromagnetic field. Different structural PAEs, including carbon chain lengths, isomers, and substituents, were evaluated for SERS performance and characteristic peaks under the optimal conditions. The SERS spectra proved that different PAEs exhibited some typically characteristic peaks in favor of recognizing and distinguishing them. The ZIF-67@Ag NWs as SERS substrate was successfully applied to detect six PAEs and exhibited wide linear ranges, low detection limit (LOD), excellent repeatability and stability (such as dibutyl phthalate DBP: linear range of 10-2 ∼ 10-12 mol/L, LOD 3 × 10-13 mol/L). The ZIF-67@Ag NWs substrate by SERS was implemented to determine trace DBP in plastics with satisfactory recoveries of 82.5 % ∼ 108.3 %. The proposed ZIF-67@Ag NWs substrate may provide an effective and promising SERS platform for recognition and quantitative determination of different structural PAEs in environment.